JP2011258003A - Programmable controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a programmable controller that allows a user to arbitrarily set a state of data output by an output module when an abnormality is detected in a CPU module.SOLUTION: The programmable controller includes an operation mode selection unit, an MPU reset circuit, and an output module reset circuit. At restart of the CPU module after detection of an abnormality, the operation mode selection unit selects whether to hold data output by an external output module or clear it. The MPU reset circuit resets an MPU based on the selected operation mode. The output module reset circuit clears the data output by the external output module. The programmable controller restarts the CPU module by resetting the MPU in a state that the data output by the external output module is held or cleared based on the selected operation mode when the abnormality is detected in the CPU module.

Description

  The present invention relates to a programmable controller, and more particularly to a technique for automatically restarting only a CPU module while maintaining or turning off output data when a serious abnormality is detected in a CPU module.

  Programmable controllers (hereinafter referred to as "PLCs") are widely used as general-purpose control devices for controlling various mechanical equipment and plant equipment installed in factories, etc., and cyclically create ladder programs created by users. It is a control device to be executed.

  The PLC is a power supply module that supplies power, an input module that inputs control signals from external sensors and switches, an output module that outputs control signals to external relays and actuators, etc., and controls and user programs for these modules CPU module.

  In such a PLC, if it is difficult to continue the calculation, or if a serious abnormality occurs that causes abnormal operation far from the user program by continuing the calculation, the CPU module detects the abnormality, The user program calculation is stopped and the operation of the PLC is stopped. In this case, it is general that the output data of the output module is turned off (deleted) and the system controlled by the PLC is stopped by a fail-safe idea that does not drive external relays or actuators in an abnormal state. . The maintenance staff went to the PLC where the abnormality occurred to eliminate the cause of the error, and the system was restored by restarting.

  In addition, serious abnormalities detected by the CPU module are often caused by transient malfunctions due to disturbances in the memory, IC, etc. used in the CPU module, and the PLC can be restarted without eliminating the error factor. There are many cases that can be recovered by turning the power on and off. For this reason, as shown in Patent Document 1, there is one that automatically restarts and automatically recovers when the PLC is abnormal.

JP 2009-104246 A

  However, if the CPU module detects a serious abnormality and stops the PLC operation, the maintenance staff will go to the site where the PLC is installed for recovery, and the method of eliminating the error factor will not be able to go to the site immediately. Under the environment, there is a problem that it takes time to restore the entire control system.

  Further, when the CPU module detects a serious abnormality and stops the PLC operation, the output data of the output module is turned off (deleted) due to the fail-safe idea. In general, there are many cases where there is no problem even if the drive system such as an electric motor is stopped as a control target, but it is a problem if the operation of the control device is stopped in a plant or the like. Furthermore, in a test operation of an external control device to be controlled, automatic recovery may not be preferred when an abnormality occurs due to reasons such as wanting to understand the cause of the abnormality.

  In order to solve the above-described conventional problems, the present invention provides a programmable controller in which a user can arbitrarily set the state of output data of an output module when an abnormality is detected.

In order to solve the conventional problems, the present invention provides various memories, an MPU that performs an operation of a sequence program, a peripheral device interface that communicates with an external programming tool, an external input signal acquisition, and an external operation result A CPU module having an external bus interface for outputting to the CPU, an external input module for transmitting an input signal from an external device to the CPU module, an external output module for holding output data of a calculation result and outputting it to the external device, In a programmable controller that controls the operation of an external device based on the calculation result of the MPU,
When restarting when an abnormality is detected in the CPU module, an operation mode selection unit is provided for selecting whether to hold or clear the output data in the external output module,
An MPU reset circuit for resetting the MPU based on the selected operation mode, and an output module reset circuit for clearing output data of the external output module;
When an abnormality is detected in the CPU module, the CPU module is restarted by resetting the MPU with the output data of the external output module being held or cleared based on the selected operation mode. .

  Further, in the programmable controller described above, the MPU reset circuit and the external output module reset circuit are installed in the CPU module, and in the case of an operation mode for holding output data in the external output module at the time of restarting, The output data of the external output module is held, and a reset signal from the MPU reset circuit is supplied to the MPU.

  In the programmable controller described above, the MPU reset circuit and the output module reset circuit are installed in the CPU module, and in the case of an operation mode in which the output data of the external output module is cleared upon restart, the external output module The reset signal of the reset circuit for a circuit is supplied to the external output module, and the reset signal from the reset circuit for the MPU is supplied to the MPU.

  In the programmable controller described above, the number of times the MPU can be automatically restarted can be set by the user, and when the number set by the user is reached, the data of the external output module is held based on the selected operation mode. Alternatively, the MPU operation is stopped in a cleared state.

  In the programmable controller described above, when the MPU is automatically restarted, information indicating that the restart has been started or is being restarted is transmitted to the programming tool, HMI, etc. connected via the peripheral device interface. It is characterized by doing.

  According to the present invention, when a serious abnormality occurs, the state of the output data of the output module can be arbitrarily set by the user according to the control target, and the CPU module can be restarted.

It is a block diagram of PLC which is one Example of this invention. It is an operation | movement flowchart at the time of abnormality detection.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a PLC according to an embodiment of the present invention.

  Reference numeral 1 denotes a PLC CPU module, which is a programming tool 2 connected to various memories, operation of a sequence program, and a communication interface unit 11, and an MPU 10 that performs communication processing with a programming tool 2 that is an application of a personal computer. An external bus interface 15 for interfacing with an input module 3 for taking in an input signal from an external device to be controlled and an output module 4 for outputting an operation result of the MPU 10 as an output signal to the external device Built in. The various memories are a non-volatile system program memory 12 storing contents and procedures controlled by the MPU 10, a rewritable sequence program memory 13 for storing a sequence program created by a user, and the MPU 10 It consists of an internal data memory 14 for storing the calculation result of the program.

  Further, a hardware reset circuit 5 is built in the CPU module 1 so that only the MPU 10 can be reset and restarted. This circuit 5 includes an MPU reset circuit 16 for resetting only the MPU 10 and the external output module. Two types of external output module reset circuit 17 to be reset are provided.

  The sequence program is created by the user with the programming tool 2 and stored in the sequence program memory 13 via the communication interface unit 11 such as USB, serial, or Ethernet (registered trademark). The programming tool 2 is provided with an operation mode selection unit 2a for selecting whether to hold or clear the output data from the external output module 4 when the CPU module 1 is restarted after an abnormality is detected. The operation modes are indicated by M1, M2, and M3, and any one mode is arbitrarily selected in advance by the user, for example, depending on the type of the control target, and the selected operation mode is stored in the system program memory 12 or the like.

  The MPU reset circuit 16 generates a reset signal in response to a restart instruction from the MPU 10. This reset signal is supplied to the MPU 10 via the gate 6. The external output module reset circuit 17 generates a reset signal, which is controlled by the MPU 10 based on the operation mode in the system program memory 12 and is supplied to the external output module 4 as a reset 18 through the gate 8. Supply is stopped. When the reset signal 18 is supplied, the output data of the external output module 4 is reset (cleared), and when the reset signal supply is stopped, the output data of the external output module 4 is held by a normal refresh process. .

The operation modes M1 to M3 in this embodiment are the following three types.
Operation mode M1:
The output data before the occurrence of the abnormality of the external output module 4 is held (refreshed), only the CPU module 1 is reset and restarted, and the PLC is automatically restored.
Operation mode M2:
The output data before the occurrence of the abnormality of the external output module 4 is turned off (reset), only the CPU module 1 is reset and restarted, and the PLC is automatically restored.
Operation mode M3:
The output data before the occurrence of the abnormality of the external output module 4 is turned OFF (reset), the user program calculation is stopped, and it waits. (Conventional operation)
In the case of the operation mode M1, the MPU 10 stops the user program calculation, does not control the output of the reset signal 18 of the reset circuit 17 for the external output module, and continues the output refresh process in the external output module 4 to generate an abnormality. The previous output data is retained and the output state is maintained. Next, in this state, a reset signal is generated in the MPU reset circuit 16 by an instruction of the MPU 10 itself, only the MPU 10 of the CPU module 1 is reset, and restarting is started. After the MPU 10 is restarted, the user program calculation is started, but the output data in the external output module 4 starts calculation in the state of the data held when the abnormality is detected.

  In the case of the operation mode M2, the MPU 10 stops the user program calculation, outputs and controls the reset signal 18 to be supplied to the external output module 4 to be reset, and the output data before the occurrence of abnormality stored in the MPU 10 is stored. It is turned off (cleared), and output of output data is stopped. Further, information indicating that only the CPU module 1 is restarted is transmitted to the programming tool 2 or the HMI (Human Machine Interface) 19 connected via the peripheral device interface 11. In this state, a reset signal is generated in the MPU reset circuit 16 by a command of the MPU 10 itself, and only the MPU 10 of the CPU module 1 is reset and restarting is started. After the MPU 10 is restarted, the user program calculation is started, but the output data for the external output module 4 is started from the OFF state.

  In the case of the operation modes M1 and M2, the CPU module 1 has a function that can be confirmed by an LED display or the like so that the restart can be visually confirmed. In addition, it has a function of leaving a log (error code, time stamp, number of restarts) and the like at the time of restart in the internal data memory 14 and the like so that maintenance personnel can check later.

  In addition, if the abnormality is not a temporary one and is a serious abnormality that does not recover even if the MPU 10 is automatically restarted several times, an error is displayed in the “Output data hold / clear” state set by the user. To stop the user program calculation. The number of automatic restarts (the number of retries) of the MPU 10 until the calculation of the user program is stopped can be designated by the user in advance.

  In the case of the operation mode 3, the MPU 10 stops the user program calculation, controls the output of the reset signal 18, and turns off (clears) the output data to the external output module 4. Then, in this state, it waits for an instruction (work) from the maintenance staff, displays error information, and waits.

  Next, an operation flow will be described based on FIG. First, when an abnormality is detected in the MPU 10 of the CPU module 1 in step 100 (S100), the abnormality content is analyzed (S101), and the operation mode is confirmed (S102). This operation mode is a mode selected in advance by the user with the programming tool 2 and stored in the system program memory 12. If the operation mode is M1, the process proceeds from S103 to S108, and the output data of the external output module 4 is held by the refresh process. In step S110, an error is displayed. In step S111, information indicating that the program is to be restarted is transmitted to the external programming tool 2 and the HMI 19 via the interface 11. In the next S112, a restart instruction is output from the MPU 10 to the MPU reset circuit 16.

  In the next S113, it is determined whether or not the number of restarts that has been designated in advance by the user has been reached, and if so, the calculation of the user program is stopped and terminated in S114. If the specified number of times has not been reached, only the MPU 10 is reset by the reset signal from the MPU reset circuit 16 in S115 and restarting is started. Next, in S116, this restart is recorded in the internal data memory 14 as a log.

  In S117, it is checked whether normal startup has been completed. If completed, calculation of the user program is started in S118. If normal startup is not completed in S117, the process returns to S101 and the abnormal content is confirmed.

  Next, if the operation mode is not M1 in S103, the process proceeds to S104. If the operation mode is M2, the process proceeds from S104 to S109, and the reset signal 18 is controlled to be output from the external output module reset circuit 17. The output data of the output module 4 is cleared. Thereafter, the process proceeds to S110, and the operations of S110 to S118 described above are performed.

  If the operation mode is not M2 in S104, it is determined that the operation mode is M3 in S105, and the output signal of the external output module 4 is controlled by outputting the reset signal 18 from the external output module reset circuit 17 in S106. To clear. Next, the process proceeds to S107, where an error is displayed, and in this state, a standby state waiting for instructions (work) from maintenance personnel is entered.

  In the above flowchart, the output data of the external output module 4 is processed (S108, S109) according to the operation mode selected by the user in preference to the restart (S111 to S115). Normal output data before the occurrence of an abnormality can be held, and the output data is less likely to be disturbed by the operation after the occurrence of the abnormality. In addition, when the output data is cleared, it is cleared quickly, so that data disturbed by the operation after the occurrence of the abnormality is not inadvertently output. Therefore, a dangerous operation is not caused on the control target due to the occurrence of an abnormality.

  As described above, when a serious abnormality occurs, the CPU module can be restarted in a state where the state of the output data of the output module is arbitrarily set by the user according to the control target.

  DESCRIPTION OF SYMBOLS 1 ... CPU module, 2 ... Programming tool (peripheral device), 3 ... External input module, 4 ... External output module, 5 ... Hard reset, 10 ... MPU, 11 ... Peripheral device interface, 12 ... System program memory, 13 ... Sequence Program memory, 14 ... Internal data memory, 15 ... External bus interface, 16 ... Reset circuit for MPU, 17 ... Reset circuit for external output module, 18 ... Reset signal, 19 ... HMI.

Claims (5)

CPU module having various memories, an MPU for calculating sequence programs, a peripheral device interface for communicating with an external programming tool, and an external bus interface for fetching external input signals and outputting calculation results to the outside And an external input module for transmitting an input signal from the external device to the CPU module, and an external output module for holding the output data of the operation result and outputting the output data to the external device, the external device based on the operation result of the MPU In the programmable controller that controls the operation of
When restarting when an abnormality is detected in the CPU module, an operation mode selection unit is provided for selecting whether to hold or clear the output data in the external output module,
An MPU reset circuit for resetting the MPU based on the selected operation mode, and an output module reset circuit for clearing output data of the external output module;
When an abnormality is detected in the CPU module, the CPU module is restarted by resetting the MPU with the output data of the external output module being held or cleared based on the selected operation mode. Programmable controller. The programmable controller according to claim 1,
The MPU reset circuit and the external output module reset circuit are installed in the CPU module, and in the case of an operation mode in which the output data in the external output module is retained at the time of restart, the output data of the external output module is retained. A programmable controller characterized by supplying a reset signal from a reset circuit to an MPU. The programmable controller according to claim 1,
The MPU reset circuit and the output module reset circuit are installed in the CPU module, and in the operation mode for clearing the output data of the external output module upon restart, the reset signal of the external output module reset circuit is sent to the external output module. And a reset signal from the MPU reset circuit is supplied to the MPU. In the programmable controller in any one of Claims 1-3,
The number of repetitions of the automatic restart of the MPU can be set by the user, and when the number set by the user is reached, the calculation of the MPU is performed with the data of the external output module held or cleared based on the selected operation mode. A programmable controller characterized by stopping the operation. In the programmable controller in any one of Claims 1-4,
A programmable controller, wherein when the MPU is automatically restarted, information indicating that the restart has been started or is being restarted is transmitted to the programming tool, HMI, and the like connected via the peripheral device interface.

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