JP2006079361A - Programmable controller and extended unit number recognition method for programmable controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a programmable controller for easily and surely making an extension unit recognize a unit number without using any mother board or mechanical switch. <P>SOLUTION: This programmable controller is configured of a CPU unit 1 and one or more extension units 2 connected to the CPU unit 1, and provided with a number transmission line 5 through which a unit number is transmitted from the CPU unit 1 to the extension unit 2 through serial communication and a line 7 for confirmation through which a confirmation signal is transmitted and received between adjacent units including the CPU 1 and the extension unit 2. In receiving the unit number, and recognizing the status change of a confirmation signal, the extension unit 2 recognizes the unit number as a number applied to its own unit, and changes the status of the confirmation signal to be outputted by its own unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a programmable controller in which an extension unit for improving functions and performance can be added to a main body that controls various devices.

  Conventionally, a CPU unit as a main body for controlling various devices, an input / output unit for increasing the number of input / output points, a dedicated arithmetic unit for specific arithmetic processing (for example, PID control), etc. as an extension unit to the CPU unit A programmable controller (hereinafter abbreviated as PLC) that can be connected is provided.

  In a PLC in which an extension unit can be provided, the CPU unit must identify each extension unit individually. Therefore, as illustrated in FIG. 5, the extension unit 11 is provided with a unit number setting unit 20 composed of signal short-circuit parts such as a DIP switch and a connector, and after setting the unit number in each extension unit 11, the CPU unit 10 A signal line 40 is provided from the CPU unit 30 to each extension unit 31 as shown in FIG. 6 to control each extension unit 11 by designating a unit number, and the unit number is assigned to each extension unit 31. There is something to be recognized (see, for example, Patent Document 1).

Further, in the case where a PLC is configured by mounting an extension unit together with a CPU unit on a motherboard provided with a plurality of connectors, there is a unit that identifies a unit number on the motherboard side.
Japanese Patent Laid-Open No. 10-69453

  However, the conventional PLC has the following problems. That is, since the PLC using the mother board is large, it is preferable not to use the mother board for the purpose of downsizing. In addition, if the unit number is set using a mechanical switch such as a dip switch, signal shorting parts such as switches and connectors are required, and it is also necessary to secure a mounting space, resulting in an increase in cost. End up. In addition, the switch setting is required by the user, so incorrect settings have been made, and switch setting has been troublesome.

  In addition, in the case of recognizing the unit number by providing a signal line from the CPU unit to each extension unit, it is necessary to prepare a signal line corresponding to the number of extension units. On the other hand, the mounting space occupied by the expansion connector of the CPU unit becomes large, and there is room for improvement in terms of cost, space, reliability, and the like.

  The present invention has been made in view of the above problems, and its object is to reduce the number of signal lines necessary for recognizing a unit number without using a motherboard or a mechanical switch, and to easily and reliably add an extension unit. An object is to provide a programmable controller capable of recognizing a unit number.

  A programmable controller according to a first aspect of the present invention is a programmable controller comprising: a CPU unit that controls an external device according to a program; and one or a plurality of additional units that are connected to the CPU unit and transmit / receive signals to / from the CPU unit. In the controller, a number transmission line in which the unit number is sent by serial communication from the CPU unit to the extension unit, a confirmation line through which a confirmation signal is transmitted and received between adjacent units including the CPU unit and the extension unit, When the extension unit receives the unit number and recognizes that the confirmation signal is in a predetermined state, the extension unit recognizes the unit number as a number assigned to itself and outputs the confirmation signal state It is characterized by changing.

  The programmable controller of the invention according to claim 2 is the programmable controller according to claim 1, wherein the confirmation line is a signal other than the confirmation signal for recognizing the unit number after all the extension units recognize the unit number. It is characterized in that it can be used for transmission and reception.

  A method for recognizing an extension unit number of a programmable controller according to a third aspect of the invention includes a CPU unit that controls an external device according to a program, and one or more extension units that are connected to the CPU unit and transmit / receive signals to / from the CPU unit. And a unit for recognizing an extension unit number in a programmable controller comprising: a number transmission line in which the unit number is sent from the CPU unit to the extension unit by serial communication; and an adjacent unit including the CPU unit and the extension unit A confirmation line through which a confirmation signal is transmitted and received, and when the extension unit receives the unit number and recognizes that the confirmation signal is in a predetermined state, the unit number is assigned to itself. Confirmation signal output by self It is characterized by changing the state.

  According to the programmable controller and the extension unit number identification method of the inventions according to claims 1 and 3, there is no need to provide a mechanical switch or the like, and the component cost and mounting space can be reduced. Further, it is not necessary to manually set individual unit numbers, so that erroneous setting can be prevented and setting man-hours can be reduced. In addition, it is not necessary to increase the number of signal lines for number identification according to the number of extension units, so that cost and space can be suppressed and reliability is improved.

  According to the programmable controller of the invention of claim 2, in addition to the effect of the invention of claim 1, the confirmation line for unit number recognition can be effectively utilized.

  Hereinafter, the present invention will be described based on embodiments.

  As illustrated in FIG. 2, the programmable controller (hereinafter abbreviated as “PLC”) of the present invention includes a CPU unit 1 and one or more extension units 2.

  The CPU unit 1 controls an external device according to a program, and has an external interface port 3 to which an editing device (not shown) for editing a sequence program or the like can be connected. The CPU unit 1 also includes a CPU side input unit 1a and a CPU side output unit 1b that connect signal lines for transmitting and receiving signals to and from an external device that is a control target. On the other hand, the expansion unit 2 is connected to the CPU unit 1 or another expansion unit 2 and transmits / receives a signal to / from the CPU 1 unit, and transmits / receives a signal to / from an external device to be controlled. An extension side input unit 2a and an extension side output unit 2b for connecting signal lines are provided.

  The CPU unit 1 and the extension unit 2 are connected to each other by a connector 4. That is, the CPU side connector 4a is provided on one surface of the CPU unit 1, the parent connector 4b is provided on one surface of each extension unit 2, and the child side connector 4c is provided on the opposite surface. Then, the CPU side connector 4a of the CPU unit 1 is connected to the parent side connector 4b of the adjacent extension unit 2 (hereinafter referred to as the first extension unit 21), and further the child side connector provided in the first extension unit 21. 4c is connected to the parent connector 4b of the adjacent extension unit 2 (hereinafter referred to as the second extension unit 22), the extension units 2 are connected in the same manner, and the required number of extension units 2 are connected. .

  FIG. 1 is a configuration diagram showing a connection state of a PLC according to the present invention. In the present invention, one signal line passing between the units connected by the connector 4 is a number transmission line 5 through which a unit number recognition command is sent from the CPU unit 1 to each extension unit 2 by serial communication. More specifically, the CPU side connector 4a, the parent side connector 4b, and the child side connector 4c have serial communication ports that transmit and receive various signals, and use the communication line by the serial communication port as the number transmission line 5. is doing. That is, the serial communication port of the CPU unit 1 serves as a command transmission unit 6, from which a unit number recognition command is transmitted simultaneously to each extension unit 2.

  Further, in the CPU side connector 4a, the parent side connector 4b, and the child side connector 4c, a port different from the serial communication port is specified, and between the adjacent units including the CPU unit 1 and the extension unit 2 from the specified port. A confirmation line 7 through which confirmation signals are transmitted and received is constructed. That is, the specific output port (Po0) of the CPU side connector 4a of the CPU unit 1, the specific input port (Pi1) of the parent side connector 4b of the first extension unit 21, and the specific output port of the child side connector 4c of the first extension unit 21 (Po1), the confirmation signal is transmitted and received through the specific input port (Pi2) of the parent connector 4b of the second extension unit 21 to the specific input port (Pin) of the parent connector 4b of the nth unit thereafter. The confirmation signal is assumed to change state from L level to H level or vice versa.

  With these number transmission line 5 and confirmation line 7, each extension unit 2 receives the unit number recognition command and confirms the state of the confirmation signal, and the confirmation signal is in a predetermined state, in this embodiment, at the H level. When it is recognized that the unit number is present, the unit number included in the command is recognized as a number assigned to itself, and on the other hand, the state of the confirmation signal output by itself is changed.

  More specifically, a unit number recognition command “n” is transmitted from the command transmission unit 6 (SIO) of the CPU unit 1 through the number transmission line 5 to each expansion unit 2, and each expansion unit 2 receives the unit number recognition command “ n ″ is received. At that time, each extension unit 2 confirms the state of the confirmation signal received through the confirmation line 7. Then, any extension unit 2 that recognizes that the state of the confirmation signal input to itself is H level recognizes that the unit number of its own station is “n”, and the confirmation signal output by itself The state is set to H level. On the other hand, when the unit number recognition command “n” is received, the other extension units 2 whose confirmation signal state is not H level do not recognize the unit number “n” and change the output of its own confirmation signal. There is nothing. In this way, each extension unit automatically recognizes its own unit number.

  Here, a detailed flow until each extension unit 2 recognizes its own unit number will be described with reference to FIGS. FIG. 3 is a flowchart of the unit number recognition command transmission of the CPU unit 1, and FIG. 4 is a flowchart when the extension unit 2 recognizes the unit number recognition command “n”.

  First, the CPU unit 1 and each extension unit 2n (n = 1... N) are powered on. When the power is turned on, the CPU unit 1 and each extension unit 2n set the output level of the confirmation signal to the low level (hereinafter abbreviated as L level) (S101, S201).

  Next, the output level of the confirmation signal from the output port (Po0) of the CPU unit 1 is set to the high level (hereinafter abbreviated as H level) (S102), and the command unit 6 recognizes the first unit number recognition command. Command “1” (S103) is transmitted.

  As illustrated in FIG. 4, each extension unit 2n that has received the command “1” (S203) confirms its own input port Pin, and if it is H level (S204), the unit number of its own station is set to “1”. Recognize (S205) and set the output port Pon of its own station to H level (S206). In the case of this example, since the signal of the input port (Pi1) of the first extension unit 21 connected to the output port (Po0) of the CPU unit 1 is at the H level, the first extension unit 21 is the unit of the own station. The number is recognized as No. 1 and the output port (Po1) of its own station is set to H. At this time, the first extension unit 21 switches the confirmation signal output so that the second extension unit 22 to which the input port (Pi2) is connected to the output port (Po1) of the first extension unit 21 does not recognize the number by mistake. The timing may be adjusted as appropriate.

  As illustrated in FIG. 3, after transmitting the command “1”, the CPU unit 1 transmits a command “2” that is a second unit number recognition command from the command transmission unit 6 (SIO) after t1 seconds ( S104). Of the extension units 2n that have received the command “2”, the extension unit 2n whose unit number has not been determined confirms the input port Pin of the own station (S202, S203). 2 is recognized (S204, S205), and the output port Pon of the own station is set to H level (S206). In the case of this example, there are the first extension unit 21 and the second extension unit 22 as the extension units whose input port Pin of the own station is at the H level at this time. Only the second extension unit 22 recognizes its own unit number as “2” by programming so as not to recognize the unit number transmitted thereafter.

  As described above, the same process is repeated until the unit numbers are recognized up to the nth extension unit 2n, and the process is repeated until all the extension units 2n have recognized the unit numbers.

  By using the method of this embodiment to make the extension unit 2 recognize the unit number, it is not necessary to provide the extension unit 2 with a switch or the like for recognizing the unit number, thereby reducing component costs and mounting space. can do. Further, when the extension unit recognizes the unit number, it is not necessary for the user to set the unit number by operating the switch by himself / herself, so that erroneous setting can be prevented and setting man-hours can be reduced. Moreover, even if the number of extension units increases, the number of signal lines does not increase, costs and space can be suppressed, and reliability is improved.

  The present embodiment is a type of PLC in which the CPU unit 1 and the first extension unit 21, the first extension unit 21 and the second extension unit 22, and the extension units are connected by connecting the connectors to each other. However, a cable may be used, and any of these connection forms may be used.

  Further, after each extension unit has recognized the unit number, the use of the confirmation line 7 connecting the CPU unit 1, the first extension unit 21, and the extension units 2 ends. Therefore, the confirmation line 7 can be used effectively by using it as a signal line for transmitting and receiving signals other than the confirmation signal for recognizing the unit number.

It is the block diagram which showed the communication method of the programmable controller of this invention. It is the external view which showed the programmable controller of this invention. It is a flowchart which shows the command transmission procedure of the CPU unit in the programmable controller of this invention. It is a flowchart which shows the unit number recognition procedure of the extension unit in the programmable controller of this invention. It is a block diagram of the communication method of the conventional programmable controller. It is a block diagram of the communication method of the conventional programmable controller.

Explanation of symbols

1. CPU unit 2. Expansion unit 4. Connector 4a. CPU side connector 4b. Parent connector 4c. 4. Child side connector Number transmission line Command transmitter 7. Confirmation line

Claims (3)

  In a programmable controller comprising a CPU unit that controls an external device according to a program, and one or a plurality of expansion units that are connected to the CPU unit and transmit / receive signals to / from the CPU unit, from the CPU unit to the expansion unit A number transmission line in which the unit number is transmitted by serial communication, and a confirmation line through which a confirmation signal is transmitted and received between adjacent units including the CPU unit and the extension unit. A programmable controller characterized in that, when receiving and recognizing that a confirmation signal is in a predetermined state, the unit number is recognized as a number assigned to itself and the state of the confirmation signal output by itself is changed.   2. The confirmation line can be used for transmission / reception of a signal other than a confirmation signal for recognizing a unit number after all extension units recognize their own unit number. Programmable controller. An expansion unit number recognition method in a programmable controller comprising: a CPU unit that controls an external device according to a program; and one or a plurality of expansion units that are connected to the CPU unit and transmit / receive signals to / from the CPU unit, A number transmission line in which the unit number is sent by serial communication from the CPU unit to the extension unit, and a confirmation line through which a confirmation signal is transmitted and received between adjacent units including the CPU unit and the extension unit; When the extension unit receives the unit number and recognizes that the confirmation signal is in a predetermined state, it recognizes the unit number as a number assigned to itself and changes the state of the confirmation signal output by itself. Programmable controller expansion unit number Recognition method.

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