JP2016081390A - Programmable logic controller and bus conversion unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow even units including a coupling face different in a kind to have a sense of integrality as a programmable logic controller.SOLUTION: A coupling unit 15 is configured to function as a conversion unit that has: a lateral face (for example: a female type/male type coupling face) of a basic unit 3a or a first lateral face (for example: a male type/female type coupling face) corresponding to a lateral face of a first extension unit 4a connected to the basic unit 3a; and a second lateral face (for example: a female type/male type coupling face) to be coupled to a lateral face (for example: a male type/female type coupling face) of a second extension unit 4b.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a programmable logic controller and a conversion unit.

  In a programmable logic controller (PLC), a plurality of extension units may be connected to a basic unit (Patent Document 1). A PLC system in which a plurality of extension units are connected to a basic unit is called a building type. The building type is further divided into a base type in which a basic unit and multiple extension units are connected on a metal base, and a baseless type in which the basic unit and multiple extension units are connected to each other without using a base. ing. In the base type, the basic unit communicates with a plurality of expansion units via a bus provided on the base. In general, in the baseless type, a bus is connected via a male and female connector provided on a connecting surface (side surface) of the basic unit and the expansion unit, and the basic unit and the expansion unit communicate via the bus. Thus, the baseless type does not require a base and is advantageous in terms of space saving.

JP 2014-052672 A

  Since the PLC is required to have high speed and responsiveness, the speed of the bus is also required. If a basic unit and an expansion unit corresponding to a high-speed bus are used, high speed and responsiveness are improved as compared with a conventional PLC including a basic unit and an expansion unit compatible with a low-speed bus. By the way, some users have a desire to utilize existing assets as much as possible. For example, if you can purchase a new high-speed basic unit and control an expansion unit with a conventional low-speed bus, you will be able to use existing assets effectively. However, high-speed buses and low-speed buses are often not compatible not only with the number of signal lines and connector shapes, but also with communication protocols. In particular, in the building type, the connection surface between the basic unit and the expansion unit may be different from the previous connection surface between the basic unit and the expansion unit due to the change of the bus. Due to such a difference in connection surface, the conventional extension unit cannot be connected to the new basic unit. If a conventional expansion unit can be connected to a new basic unit, it will be possible to realize a compact building type PLC while effectively utilizing existing assets.

  Therefore, an object of the present invention is to provide a sense of unity as a programmable logic controller even for units having different types of connection surfaces.

The present invention is, for example,
A basic unit that periodically and repeatedly executes user programs;
A first extension unit connectable to the basic unit via a first bus and configured to be connectable to another first extension unit;
A second extension unit connectable to the basic unit via at least a second bus and configured to be connectable to another second extension unit;
A conversion unit having a first side surface corresponding to a side surface of the basic unit or a side surface of the first extension unit connected to the basic unit, and a second side surface coupled to the side surface of the second extension unit; A programmable logic controller is provided.

  According to the present invention, it is possible to give a sense of unity as a programmable logic controller even if a unit having different types of connection surfaces is employed by adopting a conversion unit.

Diagram showing an example of a PLC system The figure which shows an example of the user program The figure which shows an example of a program creation assistance apparatus The figure which shows an example of PLC Diagram for explaining scan time Diagram showing an example of baseless building type PLC Diagram showing an example of the connection surface of the expansion unit Diagram for explaining the connection structure The figure which shows an example of PLC which can connect a dissimilar extension unit with a connection unit The figure which shows an example of an expansion unit and a connection unit The figure which shows the connection relation of the bus in PLC The figure which shows the connection relation of the bus in PLC The figure which shows the connection relation of the bus in PLC Diagram showing an example of the basic unit The figure which shows an example of an expansion unit and a connection unit Diagram showing an example of the basic unit The figure which shows an example of an expansion unit and a connection unit The figure which shows an example of an expansion unit and a connection unit Diagram showing an example of the basic unit The figure which shows an example of an expansion unit and a connection unit Diagram for explaining how to manage units The figure which shows an example of the refresh using a unit management table Diagram showing an example of a ladder program Diagram for explaining how to manage units Diagram for explaining how to manage units The figure which shows an example of GUI which designates the arrangement position of a unit. The figure which shows an example of GUI which designates the arrangement position of a unit. The figure which shows an example of GUI which designates the arrangement position of a unit. The figure which shows an example of GUI which designates the arrangement position of a unit. The figure which shows an example of GUI which designates the arrangement position of a unit. The figure which shows an example of GUI which designates the arrangement position of a unit. The figure which shows an example of GUI which designates the arrangement position of a unit. Diagram showing an example of a ladder program Block diagram showing functions of program creation support device Flowchart showing the method for specifying the unit location

  An embodiment of the present invention is shown below. The individual embodiments described below will help to understand various concepts, such as the superordinate concept, intermediate concept and subordinate concept of the present invention. Further, the technical scope of the present invention is determined by the scope of the claims, and is not limited by the following individual embodiments.

  First, in order to allow a person skilled in the art to better understand a programmable logic controller (PLC, which may be simply referred to as a programmable controller), the configuration and operation of a general PLC will be described.

  FIG. 1 is a conceptual diagram showing a configuration example of a programmable logic controller system according to an embodiment of the present invention. As shown in FIG. 1, this system includes a program creation support apparatus 1 for editing a user program such as a ladder program, and a PLC (programmable) for comprehensively controlling various control apparatuses installed in a factory or the like. -Logic controller 2). The PLC 2 includes a basic unit 3 having a built-in CPU and one or more expansion units 4. The plurality of expansion units 4 are units that expand the functions of the basic unit 3. One or a plurality of expansion units 4 can be attached to and detached from the basic unit 3. The basic unit 3 may be called a CPU unit.

  The basic unit 3 includes a display unit 5 and an operation unit 6. The display unit 5 can display the operation status of each expansion unit 4 attached to the basic unit 3, and the display content of the display unit 5 can be switched by operating the operation unit 6. The display unit 5 normally displays a current value (device value) of a device in the PLC 2 and error information generated in the PLC 2. The device is a name indicating an area on a memory provided for storing a device value. The device value is information indicating the input state from the input device, the output state to the output device, and the state of the internal relay (auxiliary relay), timer, counter, data memory, etc. set on the user program.

  The extension unit 4 is prepared for extending the function of the PLC 2 and is attached to the basic unit 3 from the side. The first extension unit 4 is directly attached to the basic unit 3 from the side. The second and subsequent expansion units 4 are attached in series from the side with respect to the expansion units 4 that are already attached. For example, the right side surface of the basic unit 3 and the left side surface of the expansion unit 4 are connection surfaces. Similarly, since the shape and the like of the right side surface of the first extension unit 4 are substantially the same as the right side surface of the basic unit 3, the left side of the second extension unit 4 is placed on the right side surface of the first extension unit 4. The faces are connected. Such a connection method may be called a daisy chain method or a daisy chain method. Each connection surface is provided with a connector, and a bus for performing communication and power supply is also connected through the connector. In this way, when the basic unit 3 and the plurality of expansion units 4 are attached in series, each expansion unit 4 is connected to the basic unit 3 via the wiring (eg, bus) provided in each expansion unit 4. To be communicable with each other. Each expansion unit 4 is connected to a controlled device 16 (FIG. 4) corresponding to the function of the expansion unit 4, whereby each controlled device 16 is connected to the basic unit 3 via the expansion unit 4. . The controlled device 16 includes an input device such as a sensor and an output device such as an actuator.

  The program creation support apparatus 1 is, for example, a so-called notebook type or tablet type personal computer that is portable, and includes a display unit 7 and an operation unit 8. A ladder program which is an example of a user program for controlling the PLC 2 is created using the program creation support apparatus 1, and the created ladder program is converted into a mnemonic code in the program creation support apparatus 1. Then, the program creation support apparatus 1 is connected to the basic unit 3 of the PLC 2 via a communication cable 9 such as a USB (Universal Serial Bus), and the ladder program converted into the mnemonic code is transferred from the program creation support apparatus 1 to the basic unit 3. The ladder program is converted into a machine code in the basic unit 3 and stored in a memory provided in the basic unit 3.

  Although not shown in FIG. 1, the operation unit 8 of the program creation support apparatus 1 may include a pointing device such as a mouse connected to the program creation support apparatus 1. The program creation support device 1 may be configured to be detachably connected to the basic unit 3 of the PLC 2 via a communication cable 9 other than the USB.

  FIG. 2 is a diagram illustrating an example of a ladder diagram 17 displayed on the display unit 7 of the program creation support apparatus 1 when creating a ladder program. As shown in FIG. 2, the ladder program for controlling the PLC 2 appropriately arranges virtual device symbols 19 in a plurality of cells 18 displayed in a matrix on the display unit 7 of the program creation support apparatus 1. It is created by constructing a ladder diagram 17 representing a visual relay circuit.

  In the ladder diagram 17, for example, cells 18 of 10 columns × N rows (N is an arbitrary natural number) are arranged. A visual relay circuit can be created by appropriately arranging the virtual device symbols 19 in time series in the cells 18 of each row from the left side to the right side shown in FIG. The created relay circuit may be a serial relay circuit represented by one row, or a parallel relay created by coupling relay circuits represented in parallel in a plurality of rows to each other. It may be a circuit.

  The relay circuit shown in FIG. 2 includes three virtual devices (hereinafter referred to as “input devices”) 19a, 19b, and 19c that are turned on / off based on an input signal from the input device, and the operation of the output device. And a symbol 19d of a virtual device (hereinafter referred to as an “output device”) that is turned on / off to control the device.

  The characters (“R0001”, “R0002”, and “R0003”) displayed above the symbols 19a, 19b, and 19c of each input device represent the device name (address name) 21 of the input device. The characters (“flag 1”, “flag 2”, and “flag 3”) displayed below the symbols 19a, 19b, and 19c of each input device represent a device comment 22 associated with the input device. Yes. A character (“origin return”) displayed above the symbol 19d of the output device is a label 23 composed of a character string representing the function of the output device.

  In the example shown in FIG. 2, two input device symbols 19a and 19b respectively corresponding to device names “R0001” and “R0002” are coupled in series to form an AND circuit. In addition, an OR circuit is configured by parallelly connecting the input device symbol 19c corresponding to the device name “R0003” to the AND circuit including the symbols 19a and 19b of these two input devices. Yes. That is, in this relay circuit, the output device corresponding to the symbol 19d is turned on only when both of the input devices corresponding to the two symbols 19a and 19b are turned on or when the input device corresponding to the symbol 19c is turned on. It has come to be.

  FIG. 3 is a block diagram for explaining the electrical configuration of the program creation support apparatus 1 of FIG. As shown in FIG. 3, the program creation support apparatus 1 includes a CPU 24, a display unit 7, an operation unit 8, a memory 25, and a communication unit 26. The display unit 7, the operation unit 8, the memory 25, and the communication unit 26 are electrically connected to the CPU 24, respectively. The memory 25 is configured to include at least a RAM, and includes a ladder program storage unit 25a and an editing software storage unit 25b.

  The user causes the CPU 24 to execute editing software stored in the editing software storage unit 25 b and edits the ladder program through the operation unit 8. Here, the ladder program editing includes creation and modification of the ladder program. The ladder program created using the editing software is stored in the ladder program storage unit 25a. Further, the user can read out the ladder program stored in the ladder program storage unit 25a as needed, and change the ladder program using editing software. The communication unit 26 is for connecting the program creation support apparatus 1 to the basic unit 3 through the communication cable 9 so as to be communicable.

FIG. 4 is a block diagram for explaining the electrical configuration of the PLC 2. As shown in FIG. 4, the basic unit 3 includes a CPU 10, a display unit 5, an operation unit 6, a memory 12, and a communication unit 14. The display unit 5, the operation unit 6, the memory 12, and the communication unit 14 are each electrically connected to the CPU 10.
The memory 12 may include a RAM, a ROM, a memory card, and the like, and stores a ladder program and the like. In the memory 12, the ladder program and user data input from the program creation support apparatus 1 are overwritten and stored.

  FIG. 5 is a schematic diagram showing a scan time configuration in the basic unit 3 of the programmable controller according to the embodiment of the present invention. As shown in FIG. 5, one scan time T is composed of inter-unit communication 201 for executing input / output refresh, program execution 202, and END processing 204. In the inter-unit communication 201, the basic unit 3 transmits output data obtained by executing the ladder program from the memory 12 in the basic unit 3 to an external device and the like, and also receives input data including received data as the basic unit 3. The data is taken into the internal memory 12. In the program execution 202, the basic unit 3 executes (calculates) the program using the updated input data. The basic unit 3 computes data by executing a program. The END processing means general processing related to peripheral services such as data communication with an external device such as a display (not shown) connected to the program creation support apparatus 1 or the basic unit 3, and system error checking. .

  As described above, the program creation support apparatus 1 creates a ladder program according to the user's operation, and transfers the created ladder program to the PLC 2. The PLC 2 executes the input / output refresh, the execution of the ladder program, and the END process as one cycle (one scan), and periodically and cyclically executes this cycle. Thus, various output devices (motors, etc.) are controlled based on timing signals from various input devices (sensors, etc.). Therefore, the PLC 2 moves completely different from a general-purpose personal computer (PC).

<Connection structure>
FIG. 6A shows a state before the basic unit 3, the extension unit 4 and the end unit 11 constituting the PLC 2 are connected. In this example, one or more extension units 4 are connected to the right of the basic unit 3. An end unit 11 is coupled to the rightmost extension unit 4. The end unit 11 protects the right side of the rightmost extension unit 4 and may have a bus termination function.

  FIG. 6B shows a state in which the basic unit 3, the extension unit 4 and the end unit 11 constituting the PLC 2 are connected. Since the PLC 2 is a baseless building type, the base unit 3, the extension unit 4, and the end unit 11 are connected without using a base. In order to facilitate installation on the control panel in a factory, a reference rail 13 such as a DIN rail is attached to the back surface of the PLC 2. Note that a lock mechanism may be employed to maintain the connected state of the basic unit 3 and the extension unit 4.

  FIG. 7, FIG. 8 (A) and FIG. 8 (B) are diagrams for explaining a connecting structure between units. According to FIG. 7, the expansion unit 4 has a substantially rectangular parallelepiped housing. The housing has six main side surfaces such as an upper surface 4T, a bottom surface 4B, a left side surface 4L, a right side surface 4R, a front surface 4F, and a back surface 4r. In FIG. 7, the front surface 4F faces upward. These designations for the housing surface are for convenience only.

  As shown in FIGS. 8A and 8B, a substrate 33 for transmitting an electrical signal is disposed in the housing, and a female connector 34 is fixed to one end of the reference rail 13 in the longitudinal direction. Has been. An opening 35 is provided in the right side surface 4R so that the insertion port of the female connector 34 is exposed. The left side surface 4L is provided with a male connector including a protrusion 32 that can be inserted into the insertion port of the female connector 34. A surrounding portion 31 that substantially surrounds the protruding portion 32 is provided in the housing. In this way, the male connector is formed by the protruding portion 32 and the surrounding portion 31.

  Here, it is assumed that the second extension unit 4 ′ is connected to the first extension unit 4. It should be noted that when an item common to both is described, it is simply referred to as an expansion unit 4. The surrounding portion 31 of the second extension unit is fitted or engaged with the opening 35 of the first extension unit 4. By inserting the protrusion 32 of the second extension unit 4 ′ into the insertion port of the female connector 34 of the first extension unit 4, the first and second extension units are structurally coupled to each other. The bus is electrically connected. The relationship between the female connector 34 and the protrusion 32 of the first extension unit 4 and the second extension unit 4 ′ may be reversed. That is, a male connector including the protruding portion 32 may be provided on the right side surface 4R, and a female connector 34 may be provided on the left side surface 4L. The right side surface of the basic unit 3 has the same structure as the right side surface of the expansion unit 4, and the left side surface 4 </ b> L of the expansion unit 4 is connected to the right side surface of the basic unit 3.

  The convex part integrally formed on the side surface of the first extension unit 4 is inserted into the locking hole formed on the side surface of the second extension unit 4 ′, and the convex part and the locking hole are engaged. Also good. Further, on the right side surface 4R of the expansion unit 4, a lock member 36 including a locking portion 37 that can be inserted into a wide opening portion of the lock hole 30 of the left side surface 4L is movable in the vertical direction in the figure. May be attached. More specifically, as shown in FIG. 8B, the second extension unit B1 is brought into contact with the first extension unit 4, so that the locking portion 37 of the first extension unit 4 is in the second extension. It is inserted into the lock hole 30 of the unit 4 ′. Further, when the lock member 36 of the first extension unit 4 is moved in the direction of the arrow in the figure, the engaging portion 37 of the lock member 36 has a narrow opening in the lock hole 30c of the second extension unit 4 ′. It is locked to. As a result, the second extension unit 4 ′ is locked with respect to the first extension unit 4. The locking mechanism is not particularly limited to the above example, and other locking mechanisms may be used. The installation position of the locking mechanism is not particularly limited to the above example, and may be the left side surface 4L or the like.

  As described above, the end unit 11 may be provided on the right side surface of the expansion unit 4. On the left side surface of the end unit 11, an enclosure portion that fits into the opening 35 provided on the right side surface 4 </ b> R of the extension unit 4 is provided. The shape of the surrounding portion may be similar to the shape of the surrounding portion 31, but may be a different shape as long as it fits into the opening 35. Further, a projecting portion connected to the terminating resistor may be provided in the surrounding portion of the end unit 11. As a result, a bus that needs to be terminated can be terminated by the end unit 11, and generation of unnecessary standing waves can be suppressed.

<Connection of units with different types of buses>
Updating products according to the evolution of board technology may make it impossible to maintain compatibility of the connection structure and electrical connection structure between the old product and the new product. For example, it is conceivable that the basic unit of the new product and the expansion unit of the old product are connected by a communication cable, and the connection (building) between the basic unit of the new product and the expansion unit of the old product is given up. However, this loses the advantage of the building type that connects the basic unit and the extension unit in a row. Therefore, in the present embodiment, even a plurality of types of product groups having different connection structures (connection surfaces) can be connected to improve user convenience.

  FIG. 9 is a diagram illustrating an example of the PLC 2 configured by connecting a plurality of types of extension units having different connection structures via the connection unit 15. The right side surface of the basic unit 3a and the left side surface of the extension unit 4a each have compatible connection surfaces. That is, the convex shape provided on one connecting surface is engaged with the concave shape provided on the other connecting surface, and the convex shape provided on the other connecting surface is the concave shape provided on one connecting surface. Engage. That is, the size and height of the convex shape are substantially matched with the size and depth of the concave shape. Further, the position of the convex shape and the position of the concave shape in the connection surface are also aligned. On the other hand, the left side surface of the expansion unit 4b cannot be connected to the right side surface of the basic unit 3a. That is, the connection surface of the basic unit 3a and the connection surface of the expansion unit 4b are not compatible. Therefore, the connection unit 15 absorbs the difference in connection surface, and the extension unit 4b is connected to the extension unit 4a and the basic unit 3a. The right side surface of the connecting unit 15 is configured to be compatible with the left side surface of the extension unit 4b as a connecting surface. The left side surface of the connecting unit 15 is configured to be compatible with the left side surface of the extension unit 4a and the basic unit 3a as a connecting surface. The end unit 11b may be coupled to the right side surface of the extension unit 4b that is farthest away from the basic unit 3a, that is, disposed at the far end.

  FIG. 10 is a view for explaining the structure of each connection surface of the extension unit 4a, the extension unit 4b, and the connection unit 15. As shown in FIG. The housing of the expansion unit 4a has a right side surface 4aR, a left side surface 4aL, an upper surface 4aT, a front surface 4aF, a back surface 4ar, and a bottom surface. On the right side surface 4aR, the above-described lock hole 30a, female connector 34a, and the like are provided. On the left side surface 4aL, a locking portion 37a, a protruding portion 32a of a male connector, and the like are arranged. When the locking portion 37a is inserted into the lock hole 30a and moves from the release position (large opening) to the lock position (small opening), the two connecting surfaces are locked. The female connector 34a is fitted with a protruding portion 32a of a male connector, whereby the bus is electrically connected. A groove 4ag for attaching the reference rail 13 is provided on the back surface 4ar.

  The housing of the expansion unit 4b has a right side surface 4bR, a left side surface 4bL, an upper surface 4bT, a front surface 4bF, a back surface 4br, and a bottom surface. The right side surface 4bR is provided with the lock hole 30b and the female connector 34b described above. On the left side surface 4bL, a locking portion 37b, a protruding portion 32b of a male connector, and the like are arranged. When the locking portion 37b is inserted into the lock hole 30b and moves from the release position (large opening) to the lock position (small opening), the two connecting surfaces are locked. Further, the male connector protruding portion 32b is fitted into the female connector 34b, whereby the bus is electrically connected. A groove 4bg for attaching the reference rail 13 is provided on the back surface 4br.

  The casing of the connection unit 15 has a right side surface 15R, a left side surface 15L, an upper surface 15T, a front surface 15F, a back surface 15r, and a bottom surface. The right side surface 15R is provided with the above-described lock hole 30b, female connector 34b, and the like in order to connect the left side surface 4bL of the expansion unit 4b. On the left side surface 15L, a locking portion 37a, a protruding portion 32a of a male connector, and the like are arranged to connect the expansion unit 4a and the basic unit 3a. The locking portion 37a of the connecting unit 15 is inserted into the lock hole 30a of the expansion unit 4a or the basic unit 3a, and locks the two connecting surfaces when moving from the release position (large opening) to the lock position (small opening). . Similarly, the locking portion 37b of the expansion unit 4b is inserted into the lock hole 30b of the connection unit 15. When the locking portion 37b moves from the release position (large opening) to the lock position (small opening), the two connecting surfaces are locked. The protruding portion 32b of the expansion unit 4b is fitted to the female connector 34b of the connecting unit 15, thereby electrically connecting the bus. Similarly, the protruding portion 32a of the connecting unit 15 is fitted into the female connector 34a of the expansion unit 4a or the basic unit 3a, whereby the bus is electrically connected. A groove 15g for attaching the reference rail 13 is provided on the back surface 15r.

  Thus, the connecting unit 15 is connected to the side surface of the extension unit 4b and the first side surface (the left side surface 15L) connected to the side surface of the basic unit 3a or the side surface of the extension unit 4a connected to the basic unit 3a. It functions as a connection surface conversion unit having the second side surface (right side surface 15R). That is, the basic unit 3a and the extension unit 4a are connected to the first side surface of the connecting unit 15, and the extension unit 4b is connected to the second side surface. Thus, even if the connection structure of the extension unit 4a and the connection structure of the extension unit 4b are not compatible, the connection structure of the extension unit 4a and the extension unit 4b can be connected in a row by interposing the connection unit 15. It becomes possible. In other words, even a plurality of types of extension units having different connection structures can be connected in a row, which improves user convenience. Here, the first side surface (the left side surface 15L) is connected to the side surface of the extension unit 4a. However, for example, the connection unit 15 and the basic unit 3a may be cable-connected. In this case, the first side surface (left side surface 15L) may not be connected to the side surface of the expansion unit 4a, but the side surface of the expansion unit 4a and the first side surface (left side surface 15L) are in a correspondence relationship. For example, the size (depth) in the width direction may be substantially the same on the side surface and the first side surface of the expansion unit 4a, the size in the vertical direction may be approximately the same, or both may be approximately the same. May be. In short, the basic unit 3a, the extension unit 4a, the connecting unit 15, and the extension unit 4b only need to have a corresponding relationship so as to be integrated when mounted on a reference rail such as a DIN rail.

  In the present embodiment, the baseless building type is taken as an example, but the technical idea of the present invention can also be applied to a building type PLC connected using a base frame. That is, even in a building type with a base frame, the connection structure of the extension unit 4a and the connection structure of the extension unit 4b may not be compatible, so the connection unit 15 may be employed. The base frame is fixed to, for example, the bottom surface of the extension unit 4a and the bottom surface of the extension unit 4b, and the basic unit 3a, the extension unit 4a, the extension unit 4b, and the connection unit 15 are integrally maintained by the base frame.

  A lock mechanism for fixing the basic unit 3 a or the expansion unit 4 a connected to the first side surface to the connection unit 15 may be provided on the first side surface of the connection unit 15. Such a lock mechanism may be configured by the locking portion 37a and the lock hole 30a. Similarly, a lock mechanism for fixing the expansion unit 4 b connected to the second side surface to the connection unit 15 may be provided on the second side surface of the connection unit 15. Such a lock mechanism may be configured by the locking portion 37b and the lock hole 30b.

  In FIG. 9, two extension units 4a are connected between the basic unit 3a and the connecting unit 15. However, the number of extension units 4a may be zero, or may be three or more. . One or more expansion units 4b can be connected to the right side of the connecting unit 15.

<Bus conversion unit>
In the above-described embodiments, the structural connection method for units having different connection structures has been mainly described. Hereinafter, how the basic unit 3a and the extension unit 4b communicate will be described.

  The basic unit 3a and the expansion unit 4a communicate through a bus connected via a connector provided on the coupling surface. The plurality of expansion units 4b also communicate through a bus connected via a connector. Therefore, the problem is how to connect the basic unit 3a and the expansion unit 4b by bus. For example, when the basic unit 3a and the extension unit 4a are connected via a serial bus and the plurality of extension units 4b are connected via a parallel bus, the signal lines constituting the serial bus and the signals constituting the parallel bus Communication is not possible even if the lines are connected. This is because not only the number of signal lines is different, but also the communication protocol is different.

  FIG. 11A is a diagram illustrating an example of a connection form of a plurality of different types of buses. In this example, the basic unit 3a has a female connector C1 as a first type connector. On the left side surface of the expansion unit 4a, a male connector C1 is provided as a second type connector. These connectors C1 forming a male and female connect the first bus B1 for communication between the basic unit 3a and the expansion unit 4a. In the first bus B1, for example, information on devices allocated for internal processing of the first extension unit 4a on the user program is transmitted and received. Similarly, the connector C1 connects the second bus B2. The second bus B2, for example, has characteristics different from those of the first bus B1, and communicates device information assigned to the internal processing of the second expansion unit 4b on the user program between the basic unit 3a and the second expansion unit 4b. Used to do. A first type female connector C1 is provided on the right side surface of the expansion unit 4a, and the other expansion unit 4a and the coupling unit 15 are connected to the expansion unit 4a. A male connector C <b> 1 is provided on the left side surface of the connection unit 15. The second bus B2 extends to the basic unit 3, the extension unit 4a, the connection unit 15, and the extension unit 4b. A female connector C2 is provided as a third type connector on the right side surface of the connecting unit 15 and the right side surface of the expansion unit 4b. A male connector C2 is provided on the left side surface of the expansion unit 4b as a fourth type connector. Thus, the second bus is connected by the male and female connectors C2. Since the connector C1 connects the first bus B1 and the second bus B2, more bus lines are connected than the connector C2. The basic unit 3a includes a bus master for controlling communication on the first bus B1 and a bus master for controlling communication on the second bus B2.

  FIG. 11B is a diagram illustrating an example of a connection form of a plurality of different types of buses. In this example, the basic unit 3a has a female connector C3 as a fifth type connector. A male connector C3 is provided as a sixth type connector on the left side surface of the expansion unit 4a. The male and female connectors C3 connect the first bus for communication between the basic unit 3a and the expansion unit 4a, and also connect the third bus B3. The third bus B3 is a bus obtained by converting the second bus B2 by the connecting unit 15. The communication band of the third bus B3 only needs to be equal to or greater than the communication band of the second bus B2, and any communication protocol may be used. A female connector C3 is provided on the right side surface of the extension unit 4a, and the other extension unit 4a and the connecting unit 15 are connected thereto. A male connector C3 is provided on the left side surface of the connecting unit 15. The second bus B2 extends from the connection unit 15 to the expansion unit 4b. A female connector C2 is provided on the right side surface of the connecting unit 15 and the right side surface of the expansion unit 4b. A male connector C2 is provided on the left side surface of the expansion unit 4b. Thus, the second bus is connected by the connector C2. Since the connector C1 connects the first bus B1 and the third bus B3, more bus lines are connected than the connector C2. The basic unit 3a includes a bus master for controlling communication on the first bus B1 and a bus master for controlling communication on the third bus B3. The connection unit 15 includes a bus conversion unit for performing bus conversion between the third bus B3 and the second bus B2. The bus conversion unit may have a bus master for controlling communication on the second bus B2. In FIG. 11A, since the second bus B2 extends to the extension unit 4a and the basic unit 3a, the connector C1 tends to be large. On the other hand, in FIG. 11B, the third bus B3 obtained by converting the second bus B2 extends to the expansion unit 4a and the basic unit 3a. If the number of bus lines of the third bus B3 is smaller than the bus lines of the second bus B2, the connector C3 may be smaller than the connector C1.

  FIG. 12A shows an example in which the connecting unit 15 described above is composed of two bus extension units. The bus extension unit 15a has a male connector C1, a female connector C4 which is a seventh type connector, and an eighth type connector C5 for connecting a cable. The connector C1 connects the first bus B1 and the second bus B2. The expansion unit 4a has a female connector C4 and a male connector C4. A male and female connector C4 is a connector for connecting the first bus B1. The bus extension unit 15b includes a male connector C4, a male connector C2, and a connector C5 for connecting a cable. This cable is a cable for connecting the second bus B2. Thus, the bus extension unit 15a connects the basic unit 3a or the extension unit 4a and the extension unit 4a, and connects the second bus B2 from the other bus extension unit 15b. The bus extension unit 15b connects the extension unit 4a and the extension unit 4b and connects the second bus B2 from the extension unit 15a. Thus, the second bus B2 may be connected from the extension unit 4b to the basic unit 3a without going through the extension unit 4a, that is, through the outside.

  FIG. 12B is a diagram illustrating an example of a connection form of a plurality of different types of buses. In this example, the basic unit 3a has a female connector C4. A male connector C4 is provided on the left side surface of the expansion unit 4a. These male and female connectors C4 connect the first bus B1 for communication between the basic unit 3a and the expansion unit 4a. A female connector C4 is provided on the right side surface of the expansion unit 4a, and the other expansion unit 4a and the connecting unit 15 are connected thereto. A male connector C4 is provided on the left side of the connection unit 15, and a female connector C2 is provided on the right side. A male connector C2 is provided on the left side surface of the expansion unit 4b. Thus, the second bus is connected by the connector C2. The connection unit 15 includes a bus conversion unit for performing bus conversion between the second bus B2 and the first bus B1. A part of the communication band of the first bus B1 is allocated for transmitting transmission / reception data of the second bus B2. Since the connector C4 only needs to connect the first bus B1, it can be reduced in size compared to the connector C1.

  FIG. 13 is a diagram illustrating an example in which the basic unit 3 a is integrated with the connection unit 15. In this example, the left side surface of the basic unit 3a is configured to be connected to the right side surface of the expansion unit 4a. For example, a male connector C4 is provided on the left side surface of the basic unit 3a, and is connected to a female connector C4 provided on the right side surface of the expansion unit 4a. On the other hand, the right side surface of the basic unit 3a is configured to be connected to the left side surface of the expansion unit 4b. For example, a male connector C2 is provided on the left side surface of the basic unit 3a, and is connected to a female connector C2 provided on the right side surface of the basic unit 3a. In this case, since the basic unit 3a is integrated with the connecting unit 15, there is an advantage that a bus conversion unit for converting the first bus B1 and the second bus B2 is not required.

<Configuration example of each unit>
1. Case in which the first bus B1 and the second bus B2 are connected to the basic unit 3a (part 1)
FIG. 14 is a block diagram showing functions of the basic unit 3a in the connection configuration shown in FIG. 11A, FIG. 12A, and FIG. Here, the functions realized by the memory 12 and the CPU 10 will be mainly described.

  The device memory 41 is a part of the memory 12 described above and stores device information. The ladder execution engine 42 is a part of the CPU 10 and includes a ladder execution unit 43 that executes a ladder program. The unit controller 44 is a part of the CPU 10 and controls the expansion unit 4. The unit control unit 44 controls the ladder execution unit 43 according to the holding unit (memory or the like) that holds the refresh information 45 and the scan time, and executes input / output refresh. The expansion bus master 47 is a part of the CPU 10 and controls a bus for communicating with the expansion unit 4. The bus master control unit 48 comprehensively controls one or a plurality of buses. The unit management table 49 is a table that holds identification information, a unique unit number, and the like regarding the expansion unit 4 connected to each bus. The first bus communication unit 50 is a bus master that controls communication executed via the first bus B1. The second bus communication unit 51 is a bus master that controls communication executed via the second bus B2. The bus master control unit 48 is a higher-level control unit that comprehensively controls the first bus communication unit 50 and the second bus communication unit 51. When the bus master control unit 48 receives a communication request to any one of the expansion units 4 from the ladder execution unit 43 or the scanning unit 46, the bus master control unit 48 refers to the unit management table 49 to determine which bus the expansion unit 4 is connected to. The bus master managing the specified bus is specified, and communication to the extension unit 4 is requested. The ladder execution engine 42, the unit control unit 44, and the expansion bus master 47 access the device memory 41 via the internal bus 52, and read / write data. Note that the ladder execution unit 43, the scan unit 46, and the bus master control unit 48 may be configured to communicate via the internal bus 52, or may be configured to communicate via a dedicated line. By connecting the ladder execution unit 43, the scan unit 46, and the bus master control unit 48 with the internal bus 52 and the dedicated line in this way, the ladder execution unit 43, the scan unit 46, and the bus master control unit 48 can be connected to the first bus B1 and the bus master control unit 48 at high speed. The second bus B2 and the like can be accessed. Note that the ladder execution unit 43, the scan unit 46, and the bus master control unit 48 directly access the second bus B2 without going through the first bus B1.

  FIG. 15 is a diagram illustrating communication functions provided in the extension unit 4a, the connection unit 15, and the extension unit 4b. The expansion unit 4a includes a first bus communication unit 54 that communicates with the basic unit 3a via the first bus B1. The first bus communication unit 54 functions as a slave in the first bus B1. The expansion unit 4a does not have a communication unit for the second bus B2 because it does not communicate via the second bus B2, but includes a wiring for passing the second bus B2, and further includes an amplifier circuit and a signal regeneration circuit. Etc. may be provided. Since the connection unit 15 does not perform communication with respect to both the first bus B1 and the second bus B2, it does not include a communication unit. However, the connection unit 15 includes wiring necessary for passing the second bus B2, and may further include an amplifier circuit, a signal regeneration circuit, and the like. The expansion unit 4b includes a second bus communication unit 55 that communicates with the basic unit 3a via the second bus B2. The second bus communication unit 55 functions as a slave on the second bus B2. Thus, since the second bus B2 only passes through the expansion unit 4a and the connection unit 15, signal delay hardly occurs.

2. Case in which the first bus B1 and the third bus B3 are connected to the basic unit 3a FIG. 16 is a block diagram showing functions of the basic unit 3a in the coupled configuration shown in FIG. Here, the functions realized by the memory 12 and the CPU 10 will be mainly described. In addition, about the structure already demonstrated, the simplification of description is achieved by giving the same reference number.

  The expansion bus master 47 has a third bus communication unit 53 that controls communication executed via the third bus B3. The third bus communication unit 53 functions as a bus master for the third bus B3. Since the ladder execution unit 43, the scan unit 46, and the bus master control unit 48 can access the second bus B2 via the third bus B3 without going through the first bus B1, high-speed access is realized.

  FIG. 17 is a diagram illustrating communication functions provided in the extension unit 4a, the connection unit 15, and the extension unit 4b. The expansion unit 4a does not have a communication unit for the third bus B3 because it does not communicate via the third bus B3. However, the expansion unit 4a includes wiring for passing the third bus B3, and further includes an amplifier circuit and a signal regeneration circuit. Etc. may be provided. Since the extension unit 4a only passes the third bus B3, the extension unit 4a hardly causes a signal delay. The connection unit 15 includes a first bus communication unit 56 that communicates with the basic unit 3a via the first bus B1. The first bus communication unit 56 functions as a slave in the first bus B1. The connection unit 15 includes a third bus communication unit 57 that communicates with the basic unit 3a via the third bus B3. The third bus communication unit 57 functions as a slave on the third bus B3. The connection unit 15 includes a second bus communication unit 59 that communicates with the expansion unit 4b via the second bus B2. The second bus communication unit 59 functions as a bus master in the second bus B2. The bus conversion unit 58 converts the format and protocol of communication data being executed via the second bus B2 into the format and protocol of communication data on the third bus B3. The bus conversion unit 58 converts the format and protocol of communication data being executed via the third bus B3 into the format and protocol of communication data on the second bus B2. As a result, the basic unit 3a and the expansion unit 4b can communicate via the third bus B3 and the second bus B2. Note that the bus master control unit 48 sets a communication timeout in the bus conversion unit 58 via the first bus B1, and acquires information on the expansion unit 4b connected to the second bus B2. Therefore, the basic unit 3a may manage the connection unit 15 as the expansion unit 4a having a bus conversion function. Thus, the connection unit 15 not only converts the connection surface but also converts the electrical properties of the bus.

3. Case in which the first bus B1 and the second bus B2 are connected to the basic unit 3a (part 2)
FIG. 18 is a diagram illustrating communication functions provided in the extension unit 4a, the connection units 15a and 15b, and the extension unit 4b in the connection configuration illustrated in FIG.

  The configuration of the basic unit 3a in this case is the same as that shown in FIG. This is because there is only a difference between passing the second bus B2 through the inside of the extension unit 4a or passing through the outside of the extension unit 4a. In addition, since the wiring for passing 2nd bus | bath B2 etc. are unnecessary inside the expansion unit 4a, the cost of the expansion unit 4a can be reduced.

  In FIG. 18, the connecting unit 15a has a second bus extension 60 for connecting the bus line of the second bus B2 extending from the basic unit 3a to the cable 63. The second bus extension 60 may include an amplifier circuit, a signal regeneration circuit, and the like. The other connecting unit 15b has a second bus extension 61 for connecting the cable 63 to the bus line of the second bus B2 on the extension unit 4b side. Note that the second bus extension 61 may also include an amplifier circuit, a signal regeneration circuit, and the like. As described above, the second bus extension portion 60 and the second bus extension portion 61 function as relay means, similarly to the bus conversion portion 58.

4). Case where only the first bus B1 is connected to the basic unit 3a FIG. 19 is a block diagram showing the function of the basic unit 3a in the connection configuration shown in FIG. Since the second bus communication unit 51 and the third bus communication unit 53 described above do not exist, the bus master control unit 48 controls the bus master of the second bus B2 via the first bus B1.

  FIG. 20 is a diagram illustrating communication functions provided in the extension unit 4a, the connection unit 15, and the extension unit 4b. Since the expansion unit 4a only needs to have a function of communicating via the first bus B1, the expansion unit 4a includes the first bus communication unit 54. The first bus communication unit 54 functions as a slave in the first bus B1. The connection unit 15 includes a first bus communication unit 56 that communicates with the basic unit 3a via the first bus B1. The first bus communication unit 56 also functions as a slave on the first bus B1. The connection unit 15 includes a second bus communication unit 59 that communicates with the expansion unit 4b via the second bus B2. The second bus communication unit 59 functions as a bus master in the second bus B2. The bus conversion unit 58 converts the format and protocol of communication data being executed via the second bus B2 into the format and protocol of communication data in the first bus B1. The bus conversion unit 58 converts the format and protocol of communication data being executed via the first bus B1 into the format and protocol of communication data on the second bus B2. As a result, the basic unit 3a and the expansion unit 4b can communicate with each other via the first bus B1 and the second bus B2. Note that the bus master control unit 48 sets a communication timeout in the bus conversion unit 58 via the first bus B1, and acquires information on the expansion unit 4b connected to the second bus B2. The basic unit 3a may manage the connection unit 15 as the expansion unit 4a having a bus conversion function. The connection unit 15 not only converts the connection surface but also converts the electrical properties of the bus.

<Bus control>
As described above, since there are a plurality of communication buses in the PLC 2, a bus master control unit 48 that supervises them is required. Each communication bus also requires a bus master. Therefore, in order for the basic unit 3a to communicate with any one of the extension units 4, it is specified which communication bus the extension unit 4 is connected to, and the extension unit 4 via the bus master that manages the communication bus. Need to communicate with. The bus master grasps the connection order of a plurality of expansion units connected to the bus managed by the bus master and controls communication. Further, the user needs to grasp the unit number for identifying the connection order of the plurality of expansion units when creating the ladder program. Furthermore, information on the connection order of a plurality of expansion units viewed from the basic unit 3a may be required. Since these pieces of connection information basically do not match, it is necessary to manage the relationship between the pieces of information. That is, the relationship among the connection order of the expansion units 4 viewed from the basic unit 3a, the connection order of the expansion units 4 viewed from the bus master, and the unit numbers of the expansion units 4 viewed from the user must be managed. In the present embodiment, these relationships are managed using the unit management table 49.

1. Case in which the first bus B1 and the second bus B2 are connected to the basic unit 3a (part 1)
Here, for convenience of explanation, the case shown in FIG. 11A is further expanded, and two expansion units 4a are connected between the basic unit 3a and the coupling unit 15, and two expansion units are connected to the coupling unit 15. A case where the unit 4b is connected will be used.

  FIG. 21A shows an example of connection of an extension unit to a basic unit and an example of identification information given to each unit. As shown in FIG. 21A, the extension units 4a1, 4a2 are connected to the basic unit 3a, and the extension units 4b1, 4b2 are further connected via the connecting unit 15. Here, in the basic unit 3a, a first communication unit 50 (referred to as bus master A) that functions as the bus master of the first bus B1 and a second communication unit that functions as the bus master of the second bus B2. 51 (referred to as bus master B). In addition, when the connection unit 15 is only a simple unit that absorbs the difference in connection surface, the connection unit 15 may not be provided with identification information.

  FIG. 21B is a diagram illustrating an example of the unit management table. It suffices if the unit management table 49 has the unit number, the identification information of the bus master, and the information of the connection order viewed from the bus master. However, here, for convenience of explanation, the connection order and unit name as seen from the basic unit 3a are also added.

  As shown in FIG. 21A, 0 is given to the basic unit 3a and the bus master incorporated therein. In the connection order as seen from the basic unit 3a, each unit is given a number that increases one by one as the distance from the basic unit 3a increases. As for the unit number, each unit is given a number that increases one by one in order as it moves away from the basic unit 3a. However, since the connecting unit 15 is not involved in the ladder program, no unit number is given. With respect to the connection order as seen from the bus master, the bus master is set to 0, and a number that is incremented by 1 as the distance from the bus master increases. In addition, since the connection unit 15 does not perform bus communication, a number as a connection order viewed from the bus master is not given.

  The reason why the connection order viewed from the basic unit 3a is necessary will be described. The connection order and unit number viewed from the basic unit 3a are similar connection information, but the unit number is set by the user through a ladder program, and the connection order viewed from the basic unit 3a is determined by the scanning unit 46 or the bus master control unit 48. It differs in that it is set by. For example, when the program creation support apparatus 1 is connected to the basic unit 3a and the firmware of the expansion unit 4 is updated from the program creation support apparatus 1 via the basic unit 3a, the connection order viewed from the base unit 3a is used. Then, the extension unit 4 is recognized. When the extension unit 4 having the function of communicating with another communication network receives the update program and updates the program (firmware) of the basic unit 3a, the basic unit 3a is connected as viewed from the basic unit 3a. The extension unit 4 is recognized using the order. Thus, the connection order viewed from the basic unit 3a is useful for identifying each unit in a state where no unit number is designated by the user.

  FIG. 21C shows an example of the refresh information 45. As shown in FIG. The refresh information 45 stores the unit number of the extension unit to be refreshed. The scanning unit 46 refers to the refresh information 45 to identify the extension unit to be refreshed.

  FIG. 22 is a flowchart showing each refresh process. The scan unit 46 starts the refresh when the refresh execution timing comes.

  In S <b> 1, the scanning unit 46 specifies an extension unit that is a refresh target. For example, the scanning unit 46 refers to the refresh information 45 and acquires the unit number of the target unit. According to the refresh information 45 shown in FIG. 21C, unit numbers 1, 2, and 4 are acquired.

  In S <b> 2, the scan unit 46 acquires the identification information of the bus master associated with the unit number of the identified target unit and information indicating the connection order viewed from the bus master from the unit management table 49. For example, according to FIG. 21B, the second unit number is specified as the connection order with the bus master B for the fourth unit number.

  In S <b> 3, the scan unit 46 specifies the connection order of the refresh target units and instructs the specified bus master to execute refresh. In accordance with the instruction, the bus master performs refresh on the extension unit in the designated connection order. According to FIG. 21A, the unit number 4 is assigned to the expansion unit 4b2. The bus master B is the second communication unit 51. Therefore, the scan unit 46 transmits a refresh command and connection order information indicating the expansion unit 4b2 to the second communication unit 51 through the bus master control unit 48. The second communication unit 51 performs refresh on the extension unit 4b2 to which the second connection order is assigned.

  Note that S1 to S3 are all repeatedly executed until refresh is completed for the target unit.

  By adopting the unit management table 49 in this way, even if the expansion unit 4a connected to the first bus B1 and the expansion unit 4b connected to the second bus B2 are mixed, the user is aware of it. Instead, a unit number can be assigned to each unit in the ladder program.

  Another example in which the unit management table 49 is referred will be described. The ladder execution unit 43 may access one of the extension units 4 according to a ladder program, and may read or write data. In other words, access to the expansion unit 4 may occur even at times other than the refresh timing. This is called direct processing.

  FIG. 23 is a diagram illustrating an example of a ladder program including direct processing. The ladder program is repeatedly executed at regular scan times such as 1 millisecond. That is, since refresh is executed every 1 millisecond, data cannot be acquired or written from the expansion unit unless waiting for 1 millisecond. However, it may be necessary to access the expansion unit without waiting for a millisecond. Therefore, an instruction word for executing direct processing is prepared in the ladder language.

  In FIG. 23, MR1000 indicates a relay built in the basic unit 3a. According to this ladder program, when the relay MR1000 is turned on, two processes are executed. UREAD is after an instruction to read data from the expansion unit. In the first process, the ladder execution unit 43 reads data for a word starting from the address indicated by the device DM100 of the expansion unit 4 to which unit number 1 is assigned, and the DM1000 in the device memory 41 reads the data. Write at the indicated address. More specifically, the ladder execution unit 43 refers to the unit management table 49 based on the unit number specified by the ladder program, and acquires the corresponding bus master and connection order information. According to the unit management table 49, the bus master is A, that is, the first bus communication unit 50, and the connection order is determined to be No. 1. The ladder execution unit 43 reads the data for the word from the expansion unit 4a1 assigned the first connection order to the first bus communication unit 50 through the bus master control unit 48, starting from the address indicated by the device D100. Instruct.

  In the second process, the ladder execution unit 43 reads data for a word starting from the address indicated by the device DM 200 of the expansion unit 4 that is given unit number 3, and the DM 2000 in the device memory 41 reads the data. Write at the indicated address. More specifically, the ladder execution unit 43 refers to the unit management table 49 based on the unit number specified by the ladder program, and acquires the corresponding bus master and connection order information. The bus master is B, that is, the second bus communication unit 51, and the connection order is determined to be No. 1. The ladder execution unit 43 reads data for words starting from the address indicated by the device DM200 from the expansion unit 4b1 assigned the first connection order to the second bus communication unit 51 through the bus master control unit 48. Instruct.

  Thus, the unit management table 49 is used by the scanning unit 46, the ladder execution unit 43, and the bus master control unit 48.

  FIG. 24A shows an example of connection of the extension unit to the basic unit and an example of identification information given to each unit. Here, it is assumed that the basic unit 3a, the extension units 4a and 4b, and the connecting unit 15 described with reference to FIGS. 16 and 17 are employed. The bus master A is the first bus communication unit 50, the bus master B is the second bus communication unit 59, and the bus master C is the third bus communication unit 53. The explanation will be simplified for the parts already explained.

  As shown in FIG. 24A, the second bus communication unit 59 is mounted as the bus master B in the connection unit 15, and the second bus communication unit 59 controls the second bus B2. As described above, the second bus B2 is converted by the bus converter 58 and connected to the basic unit 3a via the third bus B3. That is, the second bus communication unit 59 of the connection unit 15 is given a connection order as a slave controlled by the third bus communication unit 53 that functions as the bus master C. The connection order of the connecting units 15 is No. 1. The bus master control unit 48 inquires about the expansion unit connected to the third bus B3 through the third bus communication unit 53, and the second bus communication unit 59 of the connection unit 15 responds to the inquiry. The third bus communication unit 53 recognizes that the second bus communication unit 59 is connected to the third bus B3 as an expansion unit, and reports to the bus master control unit 48. Thereby, the bus master control unit 48 recognizes that the second bus communication unit 59 which is the bus master B of the second bus B2 is connected to the third bus B3. Next, the bus master control unit 48 accesses the second bus communication unit 59 through the third bus communication unit 53, inquires about the expansion unit connected to the second bus B2, and views the reported expansion unit from the basic unit. A number indicating the connection order and a unit number are assigned. In this way, the unit management table 49 is created.

  FIG. 24B is a diagram illustrating an example of the unit management table. According to the unit management table 49, although the unit number is not given to the connection unit 15, it is shown that it is the first unit connected to the bus master C. In addition, the bus master control unit 48 communicates with the bus conversion unit 58 of the connection unit 15 through the first bus B1, and acquires information on the expansion units 4b1 and 4b2 connected to the second bus B2. For example, when access to the expansion unit 4b1 occurs based on the unit number, the bus master control unit 48 communicates with the bus master B through the bus master C and accesses the expansion unit 4b1.

  FIG. 25A shows an example of connection of an extension unit to a basic unit and an example of identification information given to each unit. Here, it is assumed that the basic unit 3a, the extension units 4a and 4b, and the connecting unit 15 described with reference to FIGS. 19 and 20 are employed. The bus master A is the first bus communication unit 50, and the bus master B is the second bus communication unit 59. The explanation will be simplified for the parts already explained.

  As shown in FIG. 25A, the second bus communication unit 59 is mounted as the bus master B in the connection unit 15, and the second bus communication unit 59 controls the second bus B2. As described above, the second bus B2 is converted by the bus converter 58 and connected to the basic unit 3a via the first bus B1. The connection unit 15 is given a connection order as a slave controlled by the first bus communication unit 50 functioning as the bus master A. The connection order of the connecting units 15 as viewed from the bus master A is No. 3.

  FIG. 25B is a diagram illustrating an example of the unit management table. According to the unit management table 49, although the unit number is not given to the connection unit 15, it is shown that it is the third unit connected to the bus master A. In addition, the bus master control unit 48 communicates with the bus conversion unit 58 of the connection unit 15 through the first bus B1, and acquires information on the expansion units 4b1 and 4b2 connected to the second bus B2. For example, when an access to the expansion unit 4b1 occurs based on the unit number, the bus master control unit 48 communicates with the bus conversion unit 58 and the second bus communication unit 59 that are the bus master B through the first bus communication unit 50 that is the bus master A. The expansion unit 4b1 is accessed. When the bus master control unit 48 inquires of the bus conversion unit 58 about the information on the expansion unit 4b connected to the second bus B2, the bus master control unit 48 acquires the information on the expansion unit 4b via the second bus communication unit 59 to obtain the bus master. It returns to the control unit 48. This process can be executed, for example, when the first bus communication unit 50 lists units connected to itself.

  In the above-described embodiment, the example in which the plurality of extension units 4 are connected to the right side of the basic unit 3a is mainly taken up. However, the PLC that connects the plurality of extension units 4 to the left side of the basic unit 3a, or both sides of the base unit 3a. The above-described technical idea is also applicable to a PLC that connects a plurality of extension units 4 to each other.

<PLC setting GUI>
Project data including a ladder program executed by the PLC 2 is created by the program creation support apparatus 1. The user distinguishes the expansion units 4 by assigning unit numbers starting from 1 to the expansion units 4 connected to the basic unit 3a in order from the left. This distinction means distinction on the ladder program.

  By the way, the program creation support device 1 provides a GUI (Graphical User Interface) to assist the user's programming work. For example, a list for selecting a basic unit (CPU unit) used as the basic unit 3a is displayed, or a list of the expansion units 4 is displayed. The program creation support apparatus 1 displays a symbol image (which may be character information) indicating the selected basic unit on the display unit 7, and then displays the symbol image of the selected extension unit as a symbol image indicating the basic unit. Display next to Further, the program creation support apparatus 1 assigns unit numbers according to the arrangement positions of the extension units. For example, the user drags and drops the symbol image or identification information of the extension unit on the GUI to connect the symbol image of the extension unit to the symbol image of the basic unit. The unit number is determined according to the arrangement position. As a result, the user can easily assign a unit number. In addition, the user can change the arrangement of a plurality of expansion units simply by moving the symbol image on the GUI, and the unit number is also updated by the program creation support apparatus 1. Of the functions of the program creation support apparatus 1, a setting support apparatus having at least a function for setting unit configuration information related to the arrangement of the basic unit 3, the first extension unit, and the second extension unit may be provided. Here, for convenience of explanation, a unit configuration information setting support device will be described as the program creation support device 1 including a program creation support function. The unit configuration information includes a unit number for identifying each unit. The support device that creates the ladder program and transfers it to the basic unit 3 and the support device that creates the unit configuration information and transfers it to the basic unit 3 may be prepared separately.

  As described above, when different types of expansion units 4a and 4b are mixed, the physical arrangement positions of the expansion units 4a and 4b are limited. For example, the expansion unit 4 b can be arranged only on the right side of the connection unit 15, and the expansion unit 4 a can be arranged only on the left side of the connection unit 15. Therefore, the arrangement positions of the expansion units 4a and 4b must be limited even in the GUI that designates the arrangement positions of the expansion units and assigns unit numbers.

  FIG. 26 is a diagram illustrating an example of a GUI. The CPU 24 displays a GUI on the display unit 7. In this example, one of the basic units listed in the CPU model list 65 is selected by the pointer 64 that moves in conjunction with the operation of the operation unit 8. In this example, a basic unit having a model name of basic unit A1 is selected. The model number may be displayed instead of the model name, the model name and the model number may be displayed at the same time, or an explanation about the model may be displayed. When the selected basic unit is dragged by the pointer 64 and dropped in the layout area 67, the arrangement position of the basic unit is determined, and a symbol image of the basic unit is displayed at the left end of the layout area 67. The CPU model list 65 may display a symbol image or a model name. The symbol image may include a unit image together with character information indicating the model name. The symbol image may be an image in front of an actual unit.

  FIG. 27 is a diagram illustrating an example of a GUI. When the arrangement of the basic unit is completed, the extension unit is selected next. The CPU 24 displays an expansion unit list 66 listing the expansion units connectable to the selected basic unit on the display unit 7. Any expansion unit listed in the expansion unit list 66 is selected by the pointer 64, and the CPU 24 recognizes the selected expansion unit. In this example, the expansion unit a1 that can be directly connected to the basic unit A1 is selected. When the selected extension unit is dragged by the pointer 64 and dropped in the layout area 67, the CPU 24 determines the position where the extension unit can be arranged closest to the dropped position as the arrangement position of the extension unit. Displays the symbol image of the expansion unit. The CPU 24 arranges the expansion units left justified. This is because the basic unit is arranged at the left end. However, when two or more same-type extension units are already displayed in the layout area 67, the CPU 24 may insert another same-type extension unit between the two extension units according to the drop position. In this case, the connection order, unit number, and the like of the expansion units that have already been arranged are updated according to the new connection order.

  FIG. 28 is a diagram illustrating an example of a GUI. In this example, the extension unit b 1 that cannot be directly connected to the basic unit A 1 is selected by the pointer 64 and dropped in the layout area 67. Since the selected expansion unit b1 cannot be directly connected to the basic unit A1, the CPU 24 is connected to the right of the expansion unit a1 positioned at the rightmost among the plurality of expansion units connected to the basic unit A1. Is added, and the arrangement position of the expansion unit b1 is determined so as to be located right next to the connecting unit. In addition, as long as it is an expansion unit that can be directly connected to the basic unit A1, such as the expansion units a1 and a2, it can be additionally arranged anywhere between the basic unit A1 and the connecting unit. However, the CPU 24 restricts the expansion units a1 and a2 from being arranged on the right side of the connection unit. In addition, if the extension unit cannot be directly connected to the basic unit A1, such as the extension units b1 and b2, it can be additionally arranged anywhere on the right side of the connecting unit. However, the CPU 24 restricts the expansion units b1 and b2 from being arranged on the left side of the connection unit.

  FIG. 29 is a diagram illustrating an example of a GUI. In this example, the extension unit b2 is selected by the pointer 64 in a state where the extension units a1, a2, etc. are not arranged with respect to the basic unit A1, and is dropped in the layout area 67. Since the selected extension unit b1 cannot be directly connected to the basic unit A1, the CPU 24 adds a connecting unit to the right of the basic unit A1, and further determines the arrangement position of the extension unit b1 to be to the right of the connecting unit. doing. When the user attempts to place an expansion unit that requires a connection unit in the layout area 67, the CPU 24 automatically adds the connection unit. Therefore, the user does not need to worry about where to place the connecting unit, and does not need to add the connecting unit manually.

  FIG. 30 is a diagram illustrating an example of a GUI. In this example, the expansion unit b2 is selected by the pointer 64 and dropped in the layout area 67 in a state where the expansion unit a1, the connection unit, the expansion unit b1, and the like are arranged with respect to the basic unit A1. The dropped position is in the vicinity between the expansion unit a1 and the connection unit. The CPU 24 recognizes which unit's connection surface is close to the drop position by comparing the coordinates of the connection surface with the coordinates of the drop position. The coordinates of the connecting plane can be obtained by referring to the coordinates of the object (unit symbol image) displayed in the layout area 67. As described above, the expansion units b1 and b2 can be arranged only on the right side of the connection unit. Therefore, the CPU 24 determines that the extension unit b2 cannot be placed at the drop position, and outputs a warning message 69. Here, the warning message 69 is displayed on the display unit 7, but it may be output by voice or the like.

  FIG. 31 is a diagram illustrating an example of a GUI. The layout area 67 described above is graphical with a symbol image, but the arrangement of each unit may be indicated using text instead of the symbol image. According to FIG. 30, the layout area 67 is a list-like GUI, and the model name is shown together with the unit number. A model number composed of alphanumeric characters or the like may be displayed instead of the model name. In this example, the upper direction of the list indicates the direction closer to the basic unit, and the lower direction indicates the direction away from the basic unit. The CPU 24 assigns unit numbers based on the basic unit. In this example, unit numbers are not assigned to the connected units, but they may be assigned. However, as will be described later, in order not to change the unit number in the ladder program, it is desirable not to give the unit number to the connected unit.

  FIG. 32 is a diagram illustrating an example of a GUI. This example shows an example in which only the basic unit is replaced with the new basic unit A1 with respect to the PLC 2 including the old basic unit B1, the expansion unit b1, and the expansion unit b2 that are compatible only with the second bus B2. When the basic unit B1 is selected by the pointer, the CPU 24 causes the display unit 7 to display a CPU model list 65 that is a list of basic units that can be replaced with the basic unit B1. When the basic unit A1 is selected from the CPU model list 65 and dropped in the layout area 67, the CPU 24 replaces the basic unit B1 with the basic unit A1. Further, the CPU 24 arranges a connection unit for connecting the basic unit A1 and the expansion unit b1 between the basic unit A1 and the expansion unit b1.

  When the extension unit b1 and the extension unit b2 are connected to the basic unit B1, the extension unit b1 is assigned unit number 1 and the extension unit b2 is assigned number 2. Even if the basic unit B1 is changed to the basic unit A1, the CPU 24 maintains the unit number of the expansion unit b1 and the unit number of the expansion unit b2 by not assigning the unit number to the connection unit.

  FIG. 33 shows an example of a ladder program corresponding to the layout of FIG. This ladder program is for the old PLC 2 including the basic unit B1, the expansion unit b1, and the expansion unit b2, but can also be used for the new PLC 2 in which the basic unit B1 is replaced with the basic unit A1. Since the CPU 24 maintains the unit number assigned to the extension unit as it is, the user does not need to change the unit number (# 2 or # 1 in the figure) in the ladder program. Further, the CPU 24 maintains the relay number in the ladder program as it is. This is because the CPU 24 assigns a relay to the extension unit (assigns a relay number), but does not assign a relay to the connection unit. Therefore, even if the basic unit is replaced, the user does not have to change the unit number or the relay number in the ladder program created for the PLC before replacement.

  FIG. 34 is a block diagram showing functions realized by the program creation support apparatus 1. The CPU 24 implements the following functions by executing programs stored in a storage device such as a ROM.

  The memory 25 stores the CPU model list 65 and the expansion unit list 66 described above. The CPU model list 65 stores the model name, model name, description, bus type, identification information of the associated expansion unit list, and the like. The extension unit list 66 describes the model name, model name, description, bus type, and the like of the extension unit.

  FIG. 35 is a flowchart showing an example of unit layout processing. The functions realized by the CPU 24 will be described with reference to this flowchart.

  In S <b> 10, the CPU 24 displays a user interface on the display unit 7. For example, the identification information display unit 71 reads out the CPU model list 65 and displays it on the display unit 7. It should be noted that all the information in the CPU model list 65 stored in the memory 25 may be displayed, but it would be sufficient if information that makes it easy for the user to think of the model, such as the model name, is displayed.

  In S <b> 11, the CPU 24 selects a basic unit from the CPU model list 65 and arranges it in the layout area 67. For example, when the selection unit 72 is instructed to select through the operation unit 8 (when it is clicked on any of the basic units in the CPU model list 65 of the display unit 7), the CPU 72 performs the CPU relative to the display position of the pointer 64. The closest unit display position in the model list 65 is selected. The designation unit 75 designates the arrangement position of the basic unit selected by the selection unit 72 in response to a drag and drop operation with the pointer 64. The determination unit 73 designates the arrangement position of the basic unit in the layout area 67 based on the arrangement position information designated by the designation unit 75. Usually, the determination unit 73 determines the arrangement position so that the basic unit is arranged at the left end of the layout area 67. When a power supply unit that supplies power to the basic unit is arranged in the layout area 67, the determining unit 73 determines the arrangement position of the basic unit on the right side of the power supply unit. As described above, in the PLC in which the extension unit is arranged on the right side of the basic unit, the basic unit is arranged at the left end of the layout area 67. In the PLC in which the extension unit is arranged on the left side of the basic unit, the basic unit is arranged at the right end of the layout area 67. In a PLC in which expansion units are arranged on both sides of the basic unit, the basic unit may be arranged in the center of the layout area 67. The arrangement position display unit 74 displays the arrangement position of the basic unit using a symbol image or the like according to the arrangement position determined by the determination unit 73. The determination unit 73 creates layout information 80 and manages which units are arranged at which arrangement positions in the layout information 80.

  In S <b> 12, the CPU 24 reads the expansion unit list 66 associated with the selected basic unit from the memory 25 and displays it on the display unit 7. For example, the identification information display unit 71 displays identification information of one or more first extension units connectable to the first bus B1 and identification information of one or more second extension units connectable to the second bus. The extended unit list 66 including the information is displayed on the display unit 7.

  In S13, the CPU 24 selects an expansion unit and designates its arrangement position. For example, the selection unit 72 selects the identification information of the expansion unit from the expansion unit list 66 displayed by the identification information display unit 71 according to the selection operation (for example, left click) of the operation unit 8. The designation unit 75 designates the arrangement position of the extension unit selected by the selection unit 72 in response to a drag and drop operation with the pointer 64.

  In S13, the CPU 24 determines whether or not the extension unit selected by the selection unit 72 can be placed at the designated placement position. The determination unit 73 determines the type of a unit already arranged in the vicinity of the drop position, and determines whether or not the extension unit selected by the selection unit 72 can be arranged. For example, the determination unit 73 restricts the arrangement position of the first extension unit (eg, extension units a1, a2) in the layout area 67 to the side closer to the basic unit A1 than the connection unit (eg, the left side of the connection unit). Alternatively, the arrangement position of the second extension unit (eg, extension units b1, b2) may be limited to a side farther from the basic unit than the connection unit (eg, right side of the connection unit). In the layout area 67 as shown in FIG. 31, the basic unit is displayed at the upper end. Therefore, the determination unit 73 may restrict the arrangement position of the first extension unit in the layout area 67 to the upper side of the connection unit, or restrict the arrangement position of the second extension unit to the lower side of the connection unit. Good. Thus, the determination unit 73 restricts the arrangement position according to the type of the basic unit or the extension unit. If the determination unit 73 determines that the drop position of the extension unit is a position where the extension unit is prohibited from being placed, the process proceeds to S15.

  In S15, the CPU 24 (warning output unit 76) outputs a warning. This warning is a sound indicating that the arrangement is restricted or prohibited, visual information (eg, warning message 69), and the like. Thereafter, the process returns to S13.

  On the other hand, if the determination unit 73 determines in S14 that the drop position of the extension unit is a position where the arrangement of the extension unit is not restricted, the process proceeds to S16.

  In S16, the CPU 24 determines whether or not the selected extension unit is an extension unit that requires a connection unit. The determination unit 73 determines whether a connected unit is necessary based on the identification information and type of the selected extension unit. If the connecting unit is unnecessary, the process proceeds to S19. In S <b> 19, the determination unit 73 determines a position that can be placed closest to the drop position as the placement position of the extension unit. The arrangement position display unit 74 displays the symbol image of the extension unit at the arrangement position determined in the layout area 67. The determination unit 73 adds the expansion unit identification information and the arrangement position thereof to the layout information 80. On the other hand, if it determines with a connection unit being required, it will progress to S17.

  In S <b> 17, the CPU 24 (decision unit 73) refers to the layout information 80 and determines whether or not the connected unit is already arranged and displayed in the layout area 67. If the connection unit is already arranged, it is not necessary to add the connection unit to the layout area 67. In this case, the process proceeds to S19. In S <b> 19, the determination unit 73 determines the position where the disposition is closest to the drop position as the expansion unit disposition position. The arrangement position display unit 74 displays the symbol image of the extension unit at the arrangement position determined in the layout area 67.

  In S <b> 18, the CPU 24 (decision unit 73) adds a connected unit to the layout area 67. As shown in FIG. 29, when the expansion unit b1 is selected in a state where nothing is connected to the basic unit A1, the determination unit 73 causes the connection unit to be arranged next to the basic unit A1. The arrangement position of the connected unit is determined and registered in the layout information 80. As shown in FIG. 28, when the expansion unit b1 is selected in a state where the expansion unit a1 is connected to the basic unit A1, the determination unit 73 is next to the expansion unit b1 and moves to the basic unit A1. The arrangement position of the connection unit is determined so that the connection unit is arranged next to the closest side and the connection unit is arranged right next to the rightmost extension unit a1, and is registered in the layout information 80. That is, the arrangement position of the connection unit is determined so that the connection unit is arranged between the selected extension unit b1 and the rightmost extension unit a1. Thus, when the identification information of the second extension unit (extension unit b1) is selected when the connected unit is not displayed in the layout area 67, the arrangement position display unit 74 is next to the second extension unit. The connected unit is displayed next to the side closer to the basic unit. In S <b> 19, the CPU 24 (decision unit 73) determines the arrangement position of the extension unit so that the right adjacent extension unit of the connected unit is arranged, and updates the layout information 80. The arrangement position display unit 74 displays the symbol image of the extension unit in the layout area 67 according to the arrangement position of the extension unit (extension unit b1) determined by the determination unit 73.

  Incidentally, the unit number assigning unit 77 sets the unit number for identifying the arrangement position of the extension unit on the user program (ladder program) to the arrangement position of the extension unit displayed in the layout area 67 by the arrangement position display unit 74. Granted accordingly. As described with reference to FIG. 32, when only the basic unit is updated, the unit number of the expansion unit is maintained as it is without being changed. This is realized by assigning a unit number to the extension unit without assigning a unit number to the connection unit.

  The unit number assigning unit 77 deletes the first extension unit inserted between the basic unit and the second extension unit or the first extension unit connected between the base unit and the second extension unit. The unit number of the second extension unit may be maintained without being changed.

  The relay allocating unit 78 may operate so that a relay is allocated to the first expansion unit and the second expansion unit on the user program, and no relay is allocated to the connection unit. As described with reference to FIG. 33, when the basic unit is updated, the relay assigning unit 78 may maintain the relay number assigned to the relay associated with the second expansion unit without being changed. As a result, there is an advantage that even if the basic unit is changed, it is not necessary to change the unit number and the relay number in the ladder program used so far.

<Summary>
As described above, the PLC 2 has information about the first extension unit 4a and the second extension unit 4b for extending the function of the basic unit 3, and the devices assigned to the internal processing of the first extension unit 4a on the user program. The first bus (e.g., B1 or B3) for communicating between the basic unit 3 and the first extension unit 4a is different in characteristics from the first bus, and the internal processing of the second extension unit 4b on the user program The second bus B2 for communicating the information of the device assigned with respect to the basic unit 3 and the second expansion unit 4b, and the bus conversion for mutually converting the communication signal of the first bus and the communication signal of the second bus Unit (example: connecting unit 15). The first bus (eg, B1 or B3) may be a bus that connects one or more first extension units 4a to the basic unit 3a or passes through the first extension unit 4a. Good. The second bus B2 may be a bus to which one or more second expansion units 4b different from the first expansion unit 4a are connected. Note that the bus conversion unit (eg, the connecting unit 15) may not be directly connected between the first bus and the second bus. The basic unit 3 communicates with the second expansion unit via the first bus, the bus conversion unit, and the second bus. Thus, by providing the bus conversion unit, it is possible to connect even a basic unit and an expansion unit having different types of buses.

  As described with reference to FIG. 9 and the like, the basic unit 3a and the first extension unit 4a are arranged on the first side surface (eg, left side) of the connecting unit 15 that is a bus conversion unit. Further, the second extension unit 4b may be arranged on the second side surface side (eg, right side) of the bus conversion unit. As a result, it is possible to connect the first extension unit 4a and the second extension unit 4b in series by disposing the basic unit 3a at the end. As described above, a plurality of different types of expansion units may be connected to the left side of the basic unit.

  As shown in FIG. 9 and the like, the first extension unit 4a is connected to the basic unit 3a, and the first extension unit 4a connected to the basic unit 3a or another first extension unit connected to the first extension unit 4a. A connection unit 15 that is a bus conversion unit may be connected to the expansion unit 4a. Further, the second extension unit 4 b is connected to the connection unit 15.

  As described with reference to FIGS. 10 to 13 and the like, the first type connector (eg, female connector C1) is provided on the side surface of the basic unit 3a, and the first extension unit 4a and the connecting unit are provided. A first type connector and a second type connector (eg, male connector C1) may be provided on one side surface of the connector 15. Also, a first type connector (eg, female connector C1) may be provided on the other side surface of the first extension unit 4a. A third type connector (eg, female connector C2) may be provided on the other side surface of the coupling unit 15. A fourth type connector (eg, male connector C2) that forms a sex with the third type connector may be provided on one side surface of the second extension unit 4b. Similarly, a third type connector (eg, female connector C2) may be provided on the other side surface of the second extension unit 4b. In particular, the first bus B1 extends from the basic unit 3a to the connecting unit 15 via the female connector C1 and the male connector C1. Similarly, the second bus B2 extends from the connection unit 15 to the second expansion unit 4b via the female connector C2 and the male connector C2. Thus, since the connection unit 15 has the connector C1 for the first bus and the connector C2 for the second bus, the connection unit 15 may convert the first bus and the second bus.

  As described above, the PLC 2 is a baseless and building type system that does not have a base frame, but a base frame that fixes the basic unit 3a, the first extension unit 4a, the connecting unit 15, the second extension unit 4b, and the like. Furthermore, you may have. Even in a base frame type system, connection between units may be required, and the present invention will be useful.

  As described with reference to FIG. 6B, FIG. 10 and the like, attachment for attachment to the reference rail 13 is provided on the back of each of the basic unit 3a, the first extension unit 4a, the connecting unit 15 and the second extension unit 4b. Parts (4ag, 4bg, 15g) may be provided. Thereby, it becomes possible to attach the reference rail 13 in a state where the basic unit 3a, the first extension unit 4a, the connecting unit 15 and the second extension unit 4b are connected. This also makes it easier to fix the PLC 2 to a control panel such as a factory.

  The signal transfer speed of the first bus B1 may be higher than the signal transfer speed of the second bus B2. The communication speed of the bus is increasing year by year, and there is a demand for a new PLC corresponding to the high speed bus. On the other hand, if the expansion unit corresponding to the old low-speed bus can also be connected to the new PLC, the burden on the user in the transition period will be reduced. In this embodiment, by providing the connecting unit 15 which is a bus conversion unit, the basic unit 3a and the expansion unit 4a can be speeded up, and the expansion unit 4b can also be connected to them. It can be used effectively.

  The first bus B1 (third bus B3) may be a bus that executes serial transfer, for example. The second bus B2 may be a bus that executes parallel transfer. In this case, the bus conversion unit will perform serial / parallel conversion. As described above, the connection unit 15 not only absorbs the difference in connection surface but also absorbs the difference in communication method, thereby allowing a plurality of expansion units having different types of buses to be mixed.

  As described with reference to FIGS. 17 and 20, the connection unit 15 may include a bus master (for example, the second bus communication unit 59) that controls communication of the second bus B <b> 2. Thereby, it is not necessary to mount the bus master for the second bus B2 in the basic unit 3a. In addition, protocol conversion or the like can be easily implemented by the bus conversion unit 58.

  As described with reference to FIG. 10 and the like, the first side surface of the connecting unit 15 may be provided with a lock mechanism that fixes the basic unit 3a or the first extension unit 4a that engages with the first side surface. Further, a lock mechanism for fixing the second expansion unit 4b that engages with the second side surface may be provided on the second side surface of the connecting unit 15. As a result, the expansion unit can be more firmly fixed to the connecting unit 15.

  As described with reference to FIGS. 16 and 19, the basic unit 3 a is provided with the first bus control means (for example, the first bus communication unit 50) that controls communication performed on the first bus B <b> 1. May be. The connection unit 15 may be provided with second bus control means (for example, the second bus communication unit 59) that controls communication performed on the second bus B2. Further, a unit management table 49 is provided as management means for managing connection information between the first extension unit 4a connected to the first bus B1 and the second extension unit 4b connected to the second bus B2. Also good. Further, a bus master control unit 48 is provided as third control means for communicating with the expansion unit to be controlled through the first bus control means or the second bus control means according to the connection information managed by the management means. Also good. As described above, when the second bus B2 is not connected to the basic unit 3a, the basic unit 3a manages and communicates with the expansion unit 4b connected to the second bus B2 through any means. There must be. In the present embodiment, the connection information of the extension unit 4b can be managed using the unit management table 49, and communication with the extension unit 4b can be performed by referring to the unit management table 49.

  The connecting unit 15 is connected between the first bus (B1 or B3), the second bus B2, and the first bus and the second bus, and transmits the communication signal of the first bus and the communication signal of the second bus. You may have the conversion means (for example: bus conversion part 58) which converts mutually. As described above, the bus conversion unit 58 converts the signal received from the basic unit 3a via the first bus, transfers the signal to the second expansion unit 4b via the second bus, and transfers the signal from the second expansion unit 4b to the second expansion unit 4b. A signal received via the two bus B2 may be converted and transferred to the basic unit 3a via the first bus. By providing such a connecting unit 15, a plurality of expansion units that require different types of buses can be connected.

  As described with reference to FIG. 11B, FIG. 16, and FIG. 17, the PLC 2 extends from the basic unit 3a, the first bus B1, the second bus B2, and the basic unit 3a via the first extension unit 4a. And a bus conversion unit (for example, connected between the third bus B3 and the second bus B2) that mutually converts the communication signal of the third bus B3 and the communication signal of the second bus B2. : A connecting unit 15) may be included. In this case, the basic unit 3a may communicate with the second expansion unit 4b via the third bus B3, the connecting unit 15, and the second bus B2. In this case, since the first bus B1 does not need to relay the second bus B2, it will not be affected by the second bus B2. That is, the expansion unit 4a will be able to enjoy the communication band of the first bus B1 without being affected by the expansion unit 4b.

  The bus conversion unit 58 may convert the signal received from the basic unit 3a via the third bus B3 and transfer the signal to the second expansion unit 4b via the second bus B2. Similarly, the bus conversion unit 58 may convert a signal received from the second extension unit 4b via the second bus B2 and transfer the signal to the basic unit 3a via the third bus B3. As a result, the basic unit 3a and the expansion unit 4b can communicate via the second bus B2 and the third bus B3.

  As described with reference to FIGS. 15 and 18, the connecting unit 15 does not have to include an electrical bus conversion unit. Connectable to the basic unit 3a via the first bus and connected to the first extension unit 4a configured to be connectable to another first extension unit, and at least connected to the basic unit 3a via the second bus In the PLC having the second extension unit 4b that can be connected to another second extension unit, the connecting unit 15 is connected to the side surface of the basic unit 3a or the first extension unit 3a. It functions as a conversion unit having a first side corresponding to the side of the unit and a second side connected to the side of the second extension unit 4b. By adopting such a conversion unit, it is possible to provide a sense of unity as a programmable logic controller even for units having different types of connection surfaces. It is sufficient that the first side surface of the connecting unit 15 corresponds to the side surface of the first extension unit, and these need not necessarily be connected. As shown in FIG. 12A, when the bus extension units 15a and 15b which are a kind of the connection unit 15 are used, the first extension unit 4a and the extension unit 15b may or may not be connected. May be. This is because, by using the bus extension units 15a and 15b, the basic unit 3a and the second extension unit 4b can communicate with each other, and can have a sense of unity as a programmable logic controller. The side surface of the expansion unit 4a and the first side surface (left side surface 15L) are in a correspondence relationship. For example, the size (depth) in the width direction may be substantially the same on the side surface and the first side surface of the expansion unit 4a, the size in the vertical direction may be approximately the same, or both may be approximately the same. May be. In short, the basic unit 3a, the extension unit 4a, the connecting unit 15, and the extension unit 4b only need to have a corresponding relationship so as to be integrated when mounted on a reference rail such as a DIN rail.

  In addition, the connecting unit 15 includes a side surface of the basic unit 3a (eg, female / male connecting surface) or a side surface of the first extension unit 4a connected to the basic unit 3a (eg, female / male connecting surface). ) Connected to the first side surface (for example, male / female connection surface) and the second side surface (for example, male / female connection surface) of the second extension unit 4b. (Example: female / male connecting surface). As a result, even different types of units having different connection surfaces can be connected to each other. Furthermore, even if units having different types of connection surfaces are connected to each other, a building type PLC can be realized, and a PLC advantageous in terms of space saving can be realized. In addition, since existing units with different connection surfaces can be connected to new units, existing assets can be used effectively.

  As described with reference to FIG. 10 and the like, the uneven shape of the first side surface of the connecting unit 15 is a shape corresponding to the uneven shape of the side surfaces of the basic unit 3a and the first extension unit 4a. Further, the uneven shape on the second side surface of the connecting unit 15 is a shape corresponding to the uneven shape on the side surface of the second expansion unit 4b. Thereby, the difference between the uneven shape on the side surface of the basic unit 3a and the first extension unit 4a and the uneven shape on the side surface of the second extension unit 4b may be absorbed to connect the two.

  As described with reference to FIGS. 15 and 18, the connecting unit 15 is connected to the second bus B <b> 2 and relays a communication signal transmitted and received between the basic unit 3 a and the second extension unit 4 b. (Example: Wiring, second bus extension 60, 61, communication cable 63, etc.) may be included. In this case, the basic unit 3a can communicate with the second extension unit 4b via the relay unit and the second bus B2.

  Of course, as described with reference to FIGS. 17 and 20, the bus conversion unit 58 that mutually converts the communication signal of the first bus and the communication signal of the second bus is also an example of the relay unit. If the bus conversion unit 58 is employed in this way, the second bus extension units 60 and 61, the communication cable 63, and the like can be omitted. When the communication cable 63 is wired outside the PLC 2, the communication cable 63 may be damaged or disconnected, which becomes a new error factor. Therefore, reducing the number of cables wired outside the PLC 2 will lead to fewer error factors and will lead to stability of the operation of the PLC 2.

  The communication cable 63 may function as a relay unit for relaying the communication signal of the second bus B2 to the basic unit 3a. In this case, since the expansion unit 4a does not require wiring for relaying the second bus B2, the cost of the expansion unit 4a can be reduced.

  As described with reference to FIG. 15, the second bus B2 may extend through the connecting unit 15 and the first extension unit 4a to the basic unit 3a. In this case, since the connection unit 15 does not need to have a bus conversion function, a connector C5, or the like, the cost of the connection unit 15 can be reduced.

  As described above, the connecting unit 15 includes at least a second side surface connected to the side surface of the basic unit 3a or the side surface of the first extension unit 4a connected to the basic unit 3a via the first bus B1. What is necessary is just to have the 2nd side surface connected with the side surface of the 2nd expansion unit 4b connected with the basic unit 3a via bus | bath B2. As a result, even a plurality of units having incompatible connection surfaces can be connected.

  As described with reference to FIG. 27 and the like, according to the present embodiment, a setting support apparatus for setting unit configuration information regarding the arrangement of the basic unit 3a, the first extension unit 4a, and the second extension unit 4b is provided. The extension unit list 66 and the identification information display unit 71 include identification information of one or more first extension units 4a connectable to the first bus B1, and one or more second extension units connectable to the second bus B2. It functions as identification information display means for displaying the identification information of 4b. The pointer 64 and the selection unit 72 function as a selection unit that selects identification information displayed in the extension unit list 66. The determination unit 73 determines the arrangement position of the expansion unit 4 corresponding to the identification information selected by the pointer 64 or the selection unit 72 among the first expansion unit 4a and the second expansion unit 4b. The layout area 67 and the arrangement position display unit 74 function as arrangement position display means for displaying the arrangement positions of the first extension unit 4a and the second extension unit 4b with reference to the basic unit 3 according to the decided arrangement position. . As described with reference to FIG. 30 and the like, the determination unit 73 restricts the arrangement position of the extension unit 4 corresponding to the identification information according to the selected identification information. As a result, the user can easily perform the operation of arranging the expansion unit at an appropriate position.

  As described with reference to FIG. 30 and the like, the determination unit 73 may limit the arrangement position of the first extension unit 4a in the layout area 67 to the side closer to the basic unit 3a than the connection unit 15. As described above, the first extension unit 4a can be connected to the basic unit 3a and the first extension unit 4a, but cannot be connected to the second extension unit 4b. This is because the connecting surfaces are different. Further, the determination unit 73 may limit the arrangement position of the second extension unit 4b to the side farther from the basic unit 3a than the connection unit 15. This is because the second extension unit 4b cannot be directly connected to the first extension unit 4a or the basic unit 3a, and can only be connected to these via the connecting unit 15. Therefore, by restricting the arrangement of the symbol images in the layout area 67 in accordance with the connection plane restriction, the units can be arranged in the layout area 67 in a state of conforming to the connection plane restriction.

  The arrangement position display unit 74 may display the basic unit 3 a at the left end of the layout area 67. The determination unit 73 may limit the arrangement position of the first extension unit 4 a in the arrangement position display unit 74 to the left side of the connection unit 15. Further, the determination unit 73 may limit the arrangement position of the second extension unit 4 b to the right side of the connection unit 15. Thus, when the expansion units 4a and 4b are connected in series on the right side of the basic unit 3a, the expansion units 4a and 4b can be arranged easily and appropriately for the user by imposing the same restrictions on the layout area 67. Become.

  As described with reference to FIG. 31, the arrangement position display unit 74 may display the basic unit at the upper end. In this case, the determination unit 73 restricts the arrangement position of the first extension unit 4 a in the layout area 67 to the upper side of the connection unit 15 and restricts the arrangement position of the second extension unit 4 b to the lower side of the connection unit 15. May be. Thus, the actual connection direction and the connection direction in the layout area 67 do not necessarily need to match. As a result, the GUI including the layout area 67 can be simplified.

  As described with reference to FIG. 32, when the identification information of the second extension unit 4b is selected when the connection unit 15 is not displayed in the layout area 67, the arrangement position display unit 74 displays the second extension unit 4b. The connecting unit 15 may be displayed next to the base unit 3a. Thus, by automatically inserting the connecting unit 15, it is possible to save the user from having to insert the connecting unit 15 himself.

  The pointer 64 and the designation unit 75 function as designation means for designating the arrangement position of the extension unit corresponding to the selected identification information in the layout area 67. Further, the warning output unit 76 and the display unit 7 may output a warning when the arrangement position of the designated extension unit is a position where the arrangement is prohibited. This will make it easier for the user to recognize the restrictions on the arrangement position for each expansion unit.

  As described with reference to FIG. 33, the unit number assigning unit 77 sets the unit number for identifying the arrangement position of the second extension unit 4 b on the user program in the second extension unit displayed in the layout area 67. It functions as an applying means for applying according to the arrangement position. The unit number assigning unit 77 does not assign a unit number to the connecting unit 15 added between the basic unit 3a and the second extension unit 4b, thereby giving the unit number of the second extension unit 4b on the user program. maintain. This makes it easy for the user to divert the ladder program created for the previous basic unit to another basic unit.

  As described with reference to FIG. 33, the allocating unit 78 may function as a relay allocating unit that allocates a relay to the second extension unit 4 b on the user program and does not allocate a relay to the connecting unit 15. This makes it easy for the user to divert the ladder program created for the previous basic unit to another basic unit.

  As described with reference to FIGS. 26 to 32, the arrangement position display unit 74 may display the basic unit 3, the first extension unit 4a, and the second extension unit 4b as symbol images or character information. By visually recognizing the symbol image, the user can easily understand the actual unit visually. As shown in FIG. 31, it is possible to simplify the GUI by displaying units as character information.

Claims (19)

A basic unit that periodically and repeatedly executes user programs;
A first extension unit connectable to the basic unit via a first bus and configured to be connectable to another first extension unit;
A second extension unit connectable to the basic unit via at least a second bus and configured to be connectable to another second extension unit;
A conversion unit having a first side surface corresponding to a side surface of the basic unit or a side surface of the first extension unit connected to the basic unit, and a second side surface coupled to the side surface of the second extension unit; Programmable logic controller. The uneven shape on the first side surface of the conversion unit is a shape corresponding to the uneven shape on the side surface of the basic unit and the first extension unit,
2. The programmable logic controller according to claim 1, wherein the uneven shape of the second side surface of the conversion unit is a shape corresponding to the uneven shape of the side surface of the second extension unit. The conversion unit includes a relay unit that is connected to the second bus and relays communication signals transmitted and received between the basic unit and the second expansion unit.
3. The programmable logic controller according to claim 1, wherein the basic unit communicates with the second expansion unit via the relay unit and the second bus. The relay means is a bus conversion means for mutually converting the communication signal of the first bus and the communication signal of the second bus,
4. The programmable logic controller according to claim 3, wherein the basic unit communicates with the second expansion unit via the first bus, the bus conversion unit, and the second bus.   4. The programmable logic controller according to claim 3, wherein the relay unit further includes a communication cable for relaying the communication signal of the second bus to the basic unit. A first type connector is provided on a side surface of the basic unit,
A second type connector connected to the first type connector is provided on one side surface of the first extension unit and the first side surface of the conversion unit,
The first type connector is provided on the other side of the first extension unit,
A third type connector is provided on the second side surface of the conversion unit,
A fourth type connector connected to the third type connector is provided on one side surface of the second extension unit,
6. The programmable logic controller according to claim 1, wherein the third type connector is provided on the other side surface of the second expansion unit. 7. The first bus extends from the basic unit to the conversion unit via the first type connector and the second type connector;
7. The programmable device of claim 6, wherein the second bus extends from the conversion unit to the second expansion unit via the third type connector and the fourth type connector. -Logic controller.   The programmable logic controller according to any one of claims 1 to 7, further comprising a base frame for fixing the basic unit, the first extension unit, the conversion unit, and the second extension unit. .   The programmable logic controller according to any one of claims 1 to 7, wherein the programmable logic controller is a baseless and building-type system having no base frame.   The programmable unit according to claim 9, wherein an attachment portion for attachment to a reference rail is provided on each back surface of the basic unit, the first extension unit, the conversion unit, and the second extension unit. -Logic controller.   11. The programmable logic controller according to claim 1, wherein a signal transfer rate of the first bus is higher than a signal transfer rate of the second bus. The first bus is a bus that performs serial transfer;
The second bus is a bus that performs parallel transfer;
12. The programmable logic controller according to claim 1, wherein the conversion unit performs serial / parallel conversion.   The programmable logic controller according to claim 12, wherein the conversion unit includes a bus master that controls communication of the second bus. The first side surface of the conversion unit is provided with a lock mechanism for fixing the basic unit or the first extension unit connected to the first side surface,
14. The lock mechanism for fixing the second extension unit connected to the second side surface is provided on the second side surface of the conversion unit. Programmable logic controller as described.   The programmable logic controller according to claim 1, further comprising a third bus extending from the basic unit and relaying a communication signal of the second bus to the basic unit.   The programmable logic controller of claim 15, wherein the third bus is wired to pass through the first expansion unit.   The programmable logic controller of claim 1, wherein the second bus extends through the conversion unit and the first expansion unit to the basic unit. A first bus control means provided in the basic unit for controlling communication executed on the first bus;
Second bus control means provided in the bus conversion unit for controlling communication executed by the second bus;
Management means for managing connection information between the first extension unit connected to the first bus and the second extension unit connected to the second bus;
And third control means for communicating with the extension unit to be controlled through the first bus control means or the second bus control means in accordance with the connection information managed by the management means. The programmable logic controller according to any one of claims 1 to 17. A side surface of a basic unit that periodically and repeatedly executes a user program, or a first side surface coupled to a side surface of a first expansion unit connected to the basic unit via a first bus;
A conversion unit for a programmable logic controller having at least a second side surface coupled to a side surface of a second expansion unit connected to the basic unit via a second bus.