JP2007066087A - Remote terminal device for programmable controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remote terminal device for quickly performing frame communication between a communication unit and each I/O unit for reducing the substrate occupancy area of a conductor pattern for a communication line which is required for communication. <P>SOLUTION: The transmission and reception of input/output data between a communication unit and each I/O unit is performed by master/slave communication through a low rank side serial bus line, and the allocation of a unit address to each I/O unit is performed by bucket brigade communication through a uni-directional serial communication line. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a remote terminal device of a programmable controller (hereinafter referred to as PLC), and more particularly to a remote terminal device that can increase or decrease the number of I / O points in units.

  By connecting one PLC device and a plurality of remote terminal devices (also called remote I / O devices) via a field bus, load devices widely distributed in the factory are controlled with a small number of PLC devices to reduce wiring. The PLC system is widely used in large-scale production lines such as an automobile production line and an FPD (Flat Pannel Display) production line.

  The remote terminal device applied to this type of PLC system has 16 I / O points that are fixed from the beginning, such as 16 points and 32 points, and a building block type that can be increased or decreased in units. Is known. Particularly in Europe and other foreign countries, many building block types that can be increased or decreased in units are adopted.

  The building block type remote terminal apparatus includes one communication unit and one or more I / O units. The communication unit is located between a field bus that communicates with the PLC device and a lower serial bus line that communicates with each I / O unit, and functions as a gateway between the two.

  It is inconvenient if the mounting position of each I / O unit with respect to the lower serial bus line is fixed, and it is troublesome to manually set the unit address via a setting device such as a DIP switch.

  Therefore, in this type of building block type remote terminal device, on the premise of a function (free location function) in which the mounting position of each I / O unit with respect to the lower serial bus line can be freely determined. A function that can automatically assign unit addresses of I / O units is incorporated. Two configuration examples of a conventional remote terminal device incorporating such an automatic unit address assignment function are schematically shown in FIGS. 13 (a) and 13 (b).

  The first conventional example shown in FIG. 2A is a low-order serial connection between a microprocessor (hereinafter referred to as MPU) 13A built in the communication unit 1 and an MPU 21A built in each I / O unit 2. In addition to the common connection via the bus line L10, dedicated chip enable lines CE1 to CE5 are provided separately from the bus line L10 between the MPUs 21A built in each I / O unit 2, and the lower serial bus lines are provided. The unit address data sent from the MPU 13A of the communication unit 1 on L10 is received only by the MPU 21A of the I / O unit 2 in which the chip enable lines CE1 to CE5 are activated. In the figure, L0 is a field bus line leading to a PLC device (not shown).

  In the second conventional example shown in FIG. 2B, the inter-unit serial communication line L11 is connected between the communication unit 1 and the adjacent I / O unit 2 and between the adjacent I / O units 2. The initial unit address sent from the MPU 13B of the communication unit 1 is received by each I / O unit 2 from the upstream communication port and set as its own unit address. By sending out from the side communication port, unit addresses are set sequentially from the upstream side to the downstream side.

A slave station number automatic setting method for automatically setting the node numbers of a plurality of slave stations by remote control from the master station on a duplicated ring-shaped transmission line has been known (for example, patent Reference 1).
JP 07-226757 A

  However, in the first conventional example, for the main frame such as the I / O data frame, the MPU 13A of the communication unit 1 and each I / O unit 2, 2... Via the lower serial bus line L10. While having the advantage that high-speed communication can be performed directly with the MPU 21A, the number of chip enable lines CE1 to CEn corresponding to the maximum number of I / O units that can be connected is required. There is a problem that the occupied area is large.

  On the other hand, in the second conventional example, not only main frames such as I / O data frames but also address data for automatic unit address assignment are transmitted / received via the inter-unit serial communication line L11. The chip enable line for each unit is no longer required, and the area occupied by the board can be reduced by that amount. On the other hand, it is necessary to transmit and receive main frames such as I / O data frames by the bucket relay method. There is a problem that the frame communication speed between 1 and each I / O unit 2, 2.

  The present invention has been made paying attention to the above-mentioned conventional problems, and the object of the present invention is to enable high-speed frame communication between the communication unit and each I / O unit. An object of the present invention is to provide a remote terminal device in which a board occupation area such as a communication line conductor pattern required for communication is small.

  Other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description of the specification.

  The remote terminal device of the present invention employs the following configuration in order to achieve the above object.

  That is, the PLC remote terminal device according to the present invention is a remote terminal device that can be connected to the programmable controller device via the field bus, and includes a communication unit and one or more I / O units. It is out.

  The communication unit includes a first communication port for upper communication, a second communication port for lower communication, a third communication port dedicated to transmission to the lower side, an upper memory port, and a lower memory port. Data memory (eg, dual port memory) and the IN data received from the second communication port via lower communication to the pre-mapped region of the dual port memory based on the unit address attached thereto Low-order transmission / reception means for writing through the memory port, reading out the OUT data stored in each area of the dual-port memory through the low-order memory port, attaching the corresponding unit address, and transmitting from the second communication port; OUT data received from the first communication port via higher-level communication is pre-mapped in the dual port memory. A high-order memory port, and the IN data stored in each area of the dual-port memory is read via the high-order memory port and transmitted from the first communication port via the high-order communication. Side transmission / reception means.

  Each I / O unit includes a first communication port for lower-level communication, a second communication port dedicated to reception, a third communication port dedicated to transmission, an input / output circuit, and a set unit address. Unit address storage means for storing IN data from the first communication port via lower-order communication based on the unit address stored in the unit address storage means, and the unit address stored in the unit address storage means Is attached to the OUT data and transmitted via the lower communication from the first communication port, and the OUT data received via the transmission / reception means is sent to the outside via the input / output circuit, and the input / output circuit is And external input / output means for supplying IN data taken from outside via the transmission / reception means.

  Further, the communication unit is provided with first processing means for transmitting address data corresponding to the unit address initial value from the third communication port, and each I / O unit has a second processing unit. The address data received from the communication port is stored in the unit address storage means, and the address data generated by adding an offset corresponding to the number of I / O channels to the address data is sent via the third communication port. A second processing means for transmitting is provided.

  Thereby, the first communication port of the communication unit is connected to the field bus, and the second port of the communication unit and each of the first communication ports of each I / O unit are commonly connected to the lower serial bus line. Further, between the third communication port of the communication unit and the second communication port of the I / O unit adjacent thereto, and the second communication port of one unit of the pair of adjacent I / O units And the third communication port of the other unit are connected by a unidirectional serial communication line, so that input / output data transmission / reception between the communication unit and each I / O unit can be performed using a lower serial bus line. The bucket relay via the unidirectional serial communication line is used to assign unit addresses to each I / O unit while performing communication via It is performed by the trust.

  According to such a configuration, the processing for unit address allocation is performed by bucket relay communication via a unidirectional communication line, so that each I / O unit and the communication unit as in the first conventional example. It is no longer necessary to connect the two with a chip enable line, and the area occupied by the substrate can be reduced accordingly. On the other hand, frame communication between the communication unit and each of the I / O units is performed via communication via the lower serial bus line, as in the first conventional example. Unlike the bucket relay system, the frame communication speed related to input / output data does not decrease.

  In a preferred embodiment of the remote terminal device according to the present invention, in addition to the communication unit and one or more I / O units, the terminal unit further includes a termination unit, and the termination unit includes a third I / O unit. There is a grounded port to be connected to the other port.

  Further, each I / O unit includes a pull-up resistor for pulling up the third port potential to “H” level and whether the third port potential is “H” level or “L” level. And a means for storing in the I / O unit information indicating that it is an END station when the potential of the third port is determined to be “L” level by the potential determination means. It has been.

  According to such a configuration, the potential of the third communication port of the I / O unit positioned at the end is only required to be attached to the end of the I / O unit row connected to the communication unit. Since it is pulled down to the “L” level alone, it is recognized that it is an END unit based on the determination result of the potential determination means, and that fact is stored in the I / O unit.

  In a preferred embodiment of the remote terminal device according to the present invention, the communication unit transmits the address data corresponding to the initial address from the third communication port to the unidirectional serial line by the activation of the first processing means. After that, a subscription frame is transmitted to the address of each I / O unit, and the normal subscription of each I / O unit is determined based on whether or not the response arrives. After the unit information read frame is transmitted to the / O unit, an initial subscription process is provided in which the process of waiting for the response and acquiring the unit information and creating the unit information registration table is repeated until reaching the END station.

  In addition, each I / O unit stores the address data received from the second communication port as well as whether or not it is an END station by the activation of the second processing means. A process at the time of joining is provided for returning a response to the joining frame received from the communication unit and returning a response to the unit information read frame.

  According to such a configuration, since the unit address automatic assignment processing is performed via the unidirectional communication line, the completion of the unit address assignment cannot be confirmed by itself, but thereafter, each unit address via the lower serial bus line is confirmed. Since the process of confirming normal subscription is executed via communication with the I / O unit, the completion of address assignment for each I / O unit is finally confirmed.

  In a preferred embodiment of the remote terminal device according to the present invention, each I / O unit has a structure in which the main body circuit block can be attached and detached without dividing the lower serial bus line and the unidirectional serial communication line. Has been.

  In addition, the communication unit monitors the presence or absence of a communication abnormality unit, and when it is determined that there is a communication abnormality, activation of the first processing means causes address data corresponding to the initial address to be transmitted from the third communication port. After sending to the unidirectional serial line, send a join frame to the address of the I / O unit related to the abnormality, determine the normal join of each I / O unit based on the arrival of the response, and join normally When it is determined, the unit information read frame is transmitted to the I / O unit, and after waiting for the response, the unit information is acquired, and the acquired unit information and the unit information registered in the unit information registration table are displayed. A re-joining process is further provided on the unit side for performing a predetermined leaving process when the two are not matched. There.

  According to such a configuration, when an abnormality is detected in any I / O unit during operation of the remote terminal device, the unit address reallocation process is automatically executed, and then the I The normal subscription for the / O unit is determined and the configuration information is read, and the operation regarding the I / O unit is resumed only when the unit configuration information thus read matches the unit configuration information already registered. The At this time, if there is a discrepancy with the registered unit configuration information, there is a possibility that the previous unit has been removed and another unit has been newly installed. After leaving the system, operation will resume with only the remaining unit rows.

  According to the remote terminal device of the present invention, the processing for unit address assignment is performed by bucket relay communication via a unidirectional communication line, so that each I / O unit can be It is no longer necessary to connect the communication unit with a chip enable line, and the area occupied by the substrate can be reduced accordingly. On the other hand, the frame communication between the communication unit and each I / O unit is performed via master / slave communication via the lower serial bus line as in the first conventional example. Unlike the bucket relay system shown in the example, the frame communication speed relating to input / output data or the like does not decrease.

  Hereinafter, a preferred embodiment of a remote terminal device according to the present invention will be described in detail with reference to the accompanying drawings. The remote terminal device according to this embodiment includes one communication unit 1, one or more 1 / O units 2 and a termination unit 3 (see FIG. 3).

  A schematic diagram of a communication unit in the remote terminal apparatus is shown in FIG. As shown in the figure, the communication unit 1 can be connected to a PLC device (not shown) via a field bus L0.

  The communication unit 1 includes a first communication port P01 for upper communication, a second communication port P02 for lower communication, a third communication port P03 dedicated to transmission to the lower side, and an upper memory port 15a. And a lower-port side memory port 15b, a dual-port memory (referred to as DPRAM) 15, a registration unit table nonvolatile memory (EEPROM) 16, an upper communication MPU 11, a CAN driver 12, and a lower communication MPU 13 And a lower-layer communication ASIC 14.

  The upper communication MPU 11 and the CAN driver 12 cooperate with each other so that the OUT data received from the first communication port P01 via the upper communication is stored in a pre-mapped region of the dual port memory (DPRAM) 15. The upper side which writes via the upper memory port 15a and reads out the IN data stored in each area of the dual port memory 15 via the upper memory port 15a and transmits it from the first communication port P01 via the upper communication. It constitutes a transmission / reception means.

  The lower communication MPU 13 and the lower communication ASIC 14 cooperate with each other in the same manner, so that the dual port is based on the IN data received from the second communication port P02 via the lower communication based on the unit address attached thereto. Write to the pre-mapped area of the memory (DPRAM) 15 via the lower memory port 15b, and read out the OUT data stored in each area of the dual port memory 15 via the lower memory port 15b. Is attached to the lower-level transmission / reception means for transmitting from the second communication port P02.

  In the figure, reference numeral c01 is a connector for connecting the communication unit 1 and the serial bus line L0, and c02 is a connector for connecting the communication unit 1 and the adjacent I / O unit. In this example, the second communication port P02 and the third communication port P03 are derived via the connector c02.

  The lower communication MPU 13 has a transmission port TX0 for transmitting a predetermined signal to the third communication port P03 and an input port IN0 for determining the potential of the third communication port P03. Is provided. A line connecting the transmission port TX0 and the second communication port P03 is pulled up to the power supply via the resistor 17.

  Next, FIG. 2 shows a schematic configuration diagram of the I / O unit in the remote terminal device. As shown in the figure, the I / O unit 2 includes a first communication port P11 for lower-level communication, a second communication port P12 dedicated to reception, and a third communication port P13 dedicated to transmission. And an input / output circuit 23 that receives a signal (IN data) from the input device and sends a signal (OUT data) to the output device, an MPU 21 that controls the entire apparatus, and an ASIC 22 for lower-level communication. Composed.

  In addition, the I / O unit 2 includes a non-volatile memory 22a that functions as unit address storage means for storing the set unit address. In this example, the non-volatile memory is placed in the lower communication ASIC 22, but is not limited thereto, and can be placed in any location in the I / O unit 2. In the present embodiment, a nonvolatile memory is used as the unit address storage means. However, since the address is set every time the power is turned on, it is not necessarily nonvolatile.

  The MPU 21 has a reception port RX1, a transmission port TX1, and an input port IN1. The reception port RX1 is connected to the second communication port P12. The transmission port TX1 is connected to the third communication port P13. As in the case of the communication unit, the line connecting the transmission port TX1 and the third communication port P13 is pulled up to the power source via the resistor 24. Further, the potential of the third communication port P13 is read through the input port IN1, and the logical value can be determined.

  The MPU 21 and the lower-level communication ASIC 22 cooperate with each other to receive IN data from the first communication port P11 via lower-level communication based on the unit address stored in the unit address storage means (non-volatile memory 22a). The transmission / reception means for receiving and transmitting the unit address stored in the unit address storage means to the OUT data via the lower communication from the first communication port P11, and the OUT data received via the transmission / reception means It functions as external input / output means for sending out to the outside via the input / output circuit 23 and for providing IN data taken from outside via the input / output circuit 23 to the transmission / reception means.

  In the figure, reference numeral c11 is an upstream connector, and P13 is a downstream connector. In this example, the first communication port P11 and the second communication port P12 are led out via the upstream connector c11. Similarly, the first communication port P11 and the third communication port P13 are led out via the downstream connector c1.

  As shown in FIG. 12, the housing of the I / O unit 2 in the remote terminal device has a three-part configuration of a base block 201, a main body block 202, and a terminal block block 203. The base block 201 can be attached to the DIN rail 4, and the main body block 202 is detachably attached to the front side thereof. A downstream connector c12 is provided on the right side surface of the base block 201, and an upstream connector c11 is provided on the left side surface. In the base block 201, a partial conductor (not shown) that becomes a part of the serial bus line L1 is built. Therefore, when the base block 201 is mounted adjacent to the DIN rail 4 in the left-right direction, the serial bus line L1 and the unidirectional serial communication line L2 are completed. That is, the serial bus line L1 and the turn direction communication line L2 are not divided regardless of whether the main body block 202 is attached or detached.

  A main circuit board including the MPU 21 and the lower communication ASIC 22 is built in the main body block 202. The main body block 202 is detachably attached to the base block 201. The terminal block 203 is a sandwiching type terminal block in the illustrated example, and is detachably attached to the front surface of the main body block 202.

  Therefore, according to the structure of such a housing, when a failure occurs in the main body block 202 and replacement is necessary, the main body block 202 is removed from the base block 201, and the terminal is further connected to the terminal block 202. By removing the base block 203, only the main body block 202 can be easily replaced without removing the input / output cable wiring.

  Therefore, the connector c02 of the communication unit 2 and the upstream connector c11 of the 1 / O unit 2 are coupled, and further, the downstream connector c12 of the first I / O unit and the upstream of the third I / O unit. By repeating the operation of connecting the side connector c11, L1 and a series of unidirectional communication lines L2 are completed on a series of serial bus lines.

  Next, the termination unit L3 has a reception port corresponding to the third communication port P13 of the I / O unit 2 as shown in the right end of FIG. 3, and this reception port is connected to the GND. Grounded.

  Therefore, as shown in FIG. 3, if a plurality of I / O units 2, 2,... Are connected to the communication unit 1 and then the termination unit 3 is connected to the termination, the termination is connected. The MPU 21 of the 1 / O unit can recognize that the own device is an END unit by reading the potential of the port P13 through the input port 1N1.

  Next, with the communication unit 1 and the I / O unit 2 cooperating with each other, the operation of the remote terminal device according to the present invention is performed mainly on the process of automatically assigning the unit address to each I / O unit 2. explain.

  FIG. 6 shows a flowchart showing the initial joining process of the communication unit, and FIG. 8 shows a flowchart showing the address setting process of the 1 / O unit.

  First, the communication unit 1 transmits address data corresponding to the initial value (# 1) of the unit address from the third port P03 (step 601). The I / O unit 2 receives this address data from the second port P12 (step 801). Subsequently, the I / O unit 2 executes an address setting frame analysis execution process (step 802).

  A flowchart showing the address setting frame analysis execution processing of the I / O unit is shown in FIG. An explanatory diagram of the address setting frame is shown in FIG.

  As shown in FIG. 10A, the format of the address setting frame is configured by arranging “frame ID”, “data”, “frame ID inversion”, “data inversion”, and “FCS” in order. It has been done.

  In this embodiment, the types of address setting frames are “address setting frame 1”, “address setting frame 2”, “factory shipment inspection mode start frame”, and “address erasing frame”. Four types are available. For the contents of each address setting frame, refer to FIG.

  Returning to FIG. 9, in the address setting frame analysis execution process, after identifying each of the four types (steps 902, 903, 904, and 905), a predetermined operation is executed for each type.

  That is, when it is determined that the frame is “address setting frame 1”, the unit type is further identified (step 902), and the corresponding address is set in the own station according to each unit type (steps 906, 907, 908, 909), the address is incremented by the size of the own station (steps 910, 911), and the process is terminated.

  Further, when “address setting frame 2” is identified, the unit type is further identified (step 905), and after address setting processing for the own station according to the identification result (steps 912, 913, 914). 915, 916) Finally, after incrementing the address by the size of the own station (steps 917, 918, 919, 920), the process is terminated.

Returning to FIG. 8, when the address setting frame analysis execution process (step 802) is completed,
The presence / absence of the next unit is determined (step 803). Here, as described above, the presence / absence of the next unit is determined by reading the potential of the transmission port TX1 via the input port IN1, and if it is logic “H”, there is no next unit, “L”. If there is, it is determined that there is a next unit.

  If it is determined that there is a next unit (step 803 YES), the address data is transmitted from the third communication port P13 (step 804), whereas if it is determined that there is no next unit (step 803 NO), The END station is set as the own station (step 805), and the process is terminated.

  As described above, in each I / O unit 2, in response to the reception of the address (step 801), the address setting frame analysis execution process (step 802) and the address data transmission process (step 804) or One of the processes (step 805) for setting the END station to the own station is executed alternatively.

  Next, returning to FIG. 6, after executing the address data transmission process (step 601), the process for confirming the normal subscription is executed when the unit address setting in the series of I / O units is completed. To do.

  At the beginning of this process, the subscription target unit No. The initialization process (N = 1) is executed (step 602). Thereafter, a join frame is transmitted from the second port P02 by executing a join process (step 603). Then, on the I / O unit 2 side, as shown in FIG. 11, after confirming the receipt of the join frame (step 1101 YES), the join response return process (step 1102) is executed. When the reply of the joining response is received on the communication unit 1 side, it is determined that the joining is successful (step 604 YES).

  Subsequently, on the communication unit 1 side, unit information acquisition processing (step 605) is executed. In this unit information acquisition process (step 605), a unit information read frame is transmitted from the second communication port P02.

  Then, in the flowchart of FIG. 11, after the reception of the unit information read frame is confirmed (step 1103 YES), a response reply process is performed (step 1104). In this response reply process (step 1104), the configuration information (configuration information) of the own unit is transmitted to the communication unit 1.

  The unit configuration acquisition process (step 605) is completed when the unit configuration information transmitted from the I / O unit is received on the communication unit 1 side.

  Subsequently, on the communication unit 1 side, unit information registration table creation processing (step 606) is executed based on the acquired unit information. The unit information registration table created in this way is stored and saved in the registration unit table non-volatile memory (EEPROM) 16 shown in FIG.

  Subsequently, on the communication unit 1 side, the subscription target unit No. It is determined whether or not the reply is from the END station based on the contents of (step 607). Here, if it is not an END station (step 607 NO), the subscription target unit number. (N = N + 1) (step 608), the above processing (steps 603 to 607) is repeated.

  In the meantime, the subscription target unit No. If determined to be an END station based on the above (YES in step 607), the process ends.

  As described above, in this embodiment, as the initial joining process, first, address data corresponding to the initial unit address is sent from the communication unit to the adjacent I / O unit 2 via the unidirectional serial communication line L2. Then, when they reach all the I / O units sequentially in the bucket relay process, join processing is performed from the communication unit 1 to the lower serial bus line L1 (steps 602 and 603) to confirm normality. Is confirmed (step 604 YES), and unit information of each I / O unit is acquired (step 605).

  Thereafter, a unit information registration table is created based on the unit information thus obtained (step 606), and by repeating the above, automatic address assignment via the unidirectional serial communication line L2 and communication processing via the serial bus line L1 are performed. To confirm the address assignment completion, and then collect each unit information and create a unit information registration table.

  Thereafter, necessary master / slave communication processing is executed through the serial bus line L1 while referring to the registration table.

  The master / slave communication process via the serial bus line L1 is well known by various documents, and therefore detailed description thereof is omitted here.

  In the remote terminal device of this embodiment, a countermeasure when a communication abnormality occurs in any 1 / O unit is considered. FIG. 7 shows a flowchart showing the re-joining process of the communication unit.

  When processing is started in the figure, the presence or absence of communication abnormality is determined using a known communication abnormality determination algorithm. If it is determined that communication abnormality is present (YES in step 701), the following processing is executed.

  That is, first, in the same way as the initial joining process, address data corresponding to the initial unit address is transmitted from the communication unit 1 to the adjacent I / O unit 2 (step 702). The address is reassigned to the O unit.

  In this way, when the unit address assignment to a series of I / O units is completed, the communication completion processing described above is performed (step 703), and the communication subscription has been successfully completed for the unit that was previously abnormal. Is determined (step 704).

  Here, when the 1 / O unit has successfully joined the communication (YES in step 704), based on the unit information sent from the I / O unit, the unit configuration information and the unit configuration information in the registration table are Verification is performed, and it is determined whether the unit corresponding to the address is the same as the previous unit. (Step 705).

  If it is determined that the unit is the same as the registration table unit (YES in step 705), the re-subscription process is terminated, and the master / slave communication process is resumed as usual, but is different from the registration table unit. If it is determined (No in Step 705), the separation process for the unit is performed (Step 706).

  In this leaving process, a process for removing the 1 / O unit from the network is executed by various known methods, and the removed I / O unit is not to participate in the master / slave communication thereafter. Become.

  Finally, FIG. 4 is an explanatory diagram showing the unit address assignment mode by the automatic address assignment processing of the present invention. As shown in the figure, when conventional I / O units 2, 2... Are connected adjacent to the communication unit 1, each I / O unit 2, 2. From the side close to 1, addresses are allocated in the form of # 1, # 2, # 3,.

  Thereafter, as shown in the explanatory diagram of the mapping process of FIG. 5, the data (# 1ID4, # 2ID4, # 3ID4, # 4AD2) of each address-assigned I / O unit is the MPU 13 for lower communication and the data for lower communication The data is written into a predetermined input area of the dual port memory (DPRAM) 15 through the action of the ASIC 14, and thereafter sent to the PLC device via the field bus L0 in units of 8 bytes in this example.

  On the other hand, after the 8-byte OUT data coming from the PLC device via the field bus L0 is written to the predetermined input area of the dual port memory (DPRAM) 15, the lower communication MPU 13 and the lower communication ASIC 14 It is transmitted to the corresponding I / O unit (# 5OD4, # 6OD4, # 7OD4, # 8DA2).

  As described above, in the remote terminal device of the present invention, the processing for unit address assignment is performed by bucket relay communication via the unidirectional communication line L2, so that it is as in the first conventional example. In addition, it is not necessary to connect each I / O unit 2 and the communication unit 1 by the chip enable lines CE1 to CEn, so that the board occupation area can be reduced accordingly. On the other hand, frame communication between the communication unit 1 and each I / O unit 2 is performed via master / slave communication via the lower serial bus line L1, as in the first conventional example. Unlike the bucket relay system shown in the second conventional example, the frame communication speed related to input / output data does not decrease.

  In addition, according to the remote terminal device of the present invention, the unit address automatic assignment process is performed via the unidirectional communication line L2. Since the process of confirming normal subscription is executed via communication with each I / O unit 2 via the bus line L1, the completion of address allocation for each I / O unit 2 is finally confirmed. .

  Further, according to the above remote terminal device, if an abnormality is detected in any I / O unit during operation of the remote terminal device, the unit address reallocation process is automatically executed, and then the abnormality is again performed. Only when the determination of normal subscription related to the I / O unit related to the I / O unit and the reading of the configuration information thereof are performed and the unit configuration information thus read matches the unit configuration information already registered, the operation related to the I / O unit Is resumed. At this time, if there is a discrepancy with the registered unit configuration information, there is a possibility that the previous unit has been removed and another new unit has been installed. After leaving the system, operation will resume with only the remaining unit rows.

  According to the remote terminal device of the present invention, the processing for unit address assignment is performed by bucket relay communication via a unidirectional communication line, so that each I / O unit can be It is no longer necessary to connect the communication unit with a chip enable line, and the area occupied by the substrate can be reduced accordingly. On the other hand, the frame communication between the communication unit and each I / O unit is performed via master / slave communication via the lower serial bus line as in the first conventional example. Unlike the bucket relay system shown in the example, the frame communication speed relating to input / output data or the like does not decrease.

It is a schematic block diagram of the communication unit in a remote terminal device. It is a schematic block diagram of the I / O unit in a remote terminal device. It is a figure which shows the example of a connection with a communication unit, three I / O units, and a termination | terminus unit. It is explanatory drawing which shows the allocation aspect of a unit address. It is explanatory drawing of a mapping process. It is a flowchart which shows the process at the time of the initial stage joining of a communication unit. It is a flowchart which shows the process at the time of re-joining of a communication unit. It is a flowchart which shows the address setting process of an I / O unit. It is a flowchart which shows the address setting frame analysis execution process of an I / O unit. It is explanatory drawing of an address setting frame. It is a flowchart which shows the joining process of an I / O unit. It is a disassembled perspective view which shows the structure of an I / O unit. It is a block diagram of the conventional remote terminal apparatus.

Explanation of symbols

1 Communication Unit 2 I / O Unit 3 Termination Unit 11 Host Communication MPU
12 CAN driver 13 MPU for lower communication
14 ASIC for lower level communication
15 Dual port memory (DPRAM)
15a Upper side memory port 15b Lower side memory port 16 Non-volatile memory (EEPROM) for registered unit table
17 Pull-up resistor 21 MPU
22 ASIC for lower level communication
22a Non-volatile memory 23 Input / output circuit 24 Pull-up resistor L0 Field bus line L1 Downstream serial bus line L2 Unidirectional serial communication line c01, c02 Connector P01 First communication port P02 Second communication port P03 Third communication port c11, c12 connector P11 first communication port P12 second communication port P13 third communication port

Claims (4)

A remote terminal device connectable to a programmable controller device via a fieldbus,
Including a communication unit and one or more I / O units,
The communication unit is
A first communication port for host communication;
A second communication port for subordinate communication;
A third communication port dedicated to transmission to the lower side;
A data memory having an upper memory port and a lower memory port;
The IN data received from the second communication port via the lower communication is written to the pre-mapped area of the data memory based on the unit address attached thereto via the lower memory port, and each area of the data memory Low-order transmission / reception means for reading out the OUT data stored in the low-order memory port and attaching the corresponding unit address and transmitting from the second communication port;
The OUT data received from the first communication port via the upper communication is written to the pre-mapped area of the data memory via the upper memory port, and the IN data stored in each area of the data memory is An upper side transmitting / receiving means for reading out from the first communication port via the memory port and transmitting via the upper communication,
Each I / O unit is
A first communication port for subordinate communication;
A second communication port dedicated to reception;
A third communication port dedicated to transmission;
An input / output circuit;
Unit address storage means for storing the set unit address;
Based on the unit address stored in the unit address storage means, IN data is received from the first communication port via lower communication, and the unit address stored in the unit address storage means is attached to the OUT data as the first data. A transmission / reception means for transmitting from the communication port via lower communication,
An external input / output means for sending out OUT data received via the transmission / reception means to the outside via the input / output circuit and for giving the IN data captured from the outside via the input / output circuit to the transmission / reception means; Furthermore, the communication unit is provided with a first processing means for transmitting address data corresponding to the unit address initial value from the third communication port, and each I / O unit has a second communication unit. The address data received from the port is stored in the unit address storage means, and the address data generated by adding an offset corresponding to the number of I / O channels to the address data is transmitted via the third communication port. A second processing means is provided,
Thereby, the first communication port of the communication unit is connected to the field bus, and the second port of the communication unit and each of the first communication ports of each I / O unit are commonly connected to the lower serial bus line. Further, between the third communication port of the communication unit and the second communication port of the I / O unit adjacent thereto, and the second communication port of one unit of the pair of adjacent I / O units And the third communication port of the other unit are connected by a unidirectional serial communication line, so that input / output data transmission / reception between the communication unit and each I / O unit can be performed using a lower serial bus line. The bucket relay via the unidirectional serial communication line is used to assign unit addresses to each I / O unit while performing communication via Performed by Shin, remote terminal device of the programmable controller, characterized in that. In addition to the communication unit and one or more I / O units, the terminal unit further includes a termination unit, and the termination unit is provided with a ground port to be connected to the third port of the I / O unit. In addition, each I / O unit
A pull-up resistor for pulling up the potential of the third port to the “H” level;
A potential determining means for determining whether the potential of the third port is “H” level or “L” level;
And a means for storing, in the I / O unit, information indicating that the third port is an END station when the potential of the third port is determined to be "L" level by the potential determination means. Item 12. A remote terminal device for a programmable controller according to Item 1. The communication unit includes
After the address data corresponding to the initial address is transmitted from the third communication port to the unidirectional serial line by the activation of the first processing means, the subscription frame is transmitted to the address of each I / O unit. Based on whether or not the response has arrived, the normal joining of each I / O unit is determined. When it is determined that the joining is normal, a unit information read frame is transmitted to the I / O unit and the response is waited for. Initial subscription processing is provided that repeats the process of acquiring unit information and creating the unit information registration table up to the END station,
Each I / O unit has a
Activating the second processing means, storing the address data received from the second communication port, and storing whether or not it is an END station, and then returning a response to the subscription frame received from the communication unit; In addition, there is provided a process at the time of sending back a response to the unit information read frame,
The remote terminal apparatus of the programmable controller according to claim 2. Each I / O unit has a structure in which the main body block can be attached and detached without dividing the lower serial bus line and the unidirectional serial communication line.
The communication unit includes
The presence or absence of a communication abnormality unit is monitored, and when it is determined that there is a communication abnormality, address data corresponding to the initial address is transmitted from the third communication port to the unidirectional serial line by activation of the first processing means. Then, a subscription frame is transmitted to the address of the I / O unit related to the abnormality, and the normal subscription of each I / O unit is determined based on whether or not the response has arrived. After sending the unit information read frame to the / O unit, waiting for the response, the unit information is acquired, the acquired unit information is compared with the unit information registered in the unit information registration table, and the two do not match In this case, a re-joining process on the unit side for performing a predetermined withdrawal process is further provided. Programmable controller remote terminal apparatus according to claim 3.

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