Programmable logic controller (PLC) simulation system, PLC simulator, recording medium, and simulation method

A PLC simulator that cyclically repeats processing based on a first cycle, comprising:

• a storage unit for holding data for executing a program, the storage unit being configured to be accessed by the PLC simulator and an external simulator that cyclically repeats processing based on a second cycle;
• and
• a processor communicatively connected to the storage unit, the processor comprising an execution unit for executing a program accompanying processing for inputting and outputting data to and from the storage unit,
• wherein the execution unit includes a detection unit for detecting that program execution in the external simulator is complete, and, after executing the program, suppresses execution of a program accompanying access to the storage unit, until the detection is performed by the detection unit,
• wherein the PLC simulator comprises a socket interface for communicating with the external simulator, in which the PLC simulator receives a command from the external simulator for causing the PLC simulator to execute predetermined processing,
• wherein the execution unit executes processing in accordance with the command received using the socket interface,
• wherein the command includes a notification command for notifying the external simulator of a status of program execution by the execution unit.

A PLC simulator that cyclically repeats processing based on a first cycle, comprising:

• an interface for transmitting and receiving information to and from an external simulator that cyclically repeats processing based on a second cycle;
• a storage unit for holding data for executing a program, the storage unit being configured to be accessed by the PLC simulator and the external simulator;
• and
• a processor communicatively connected to the storage unit, the processor comprising an execution unit for executing a program accompanying processing for inputting and outputting data to and from the storage unit,
• wherein the execution unit notifies the external simulator of a status of program execution, using the interface,
• wherein the interface comprises a socket interface for communicating with the external simulator, wherein the PLC simulator receives a command from the external simulator for causing the PLC simulator to execute predetermined processing,
• wherein the execution unit executes processing in accordance with the command received using the socket interface, and
• wherein the command includes a notification command for notifying the external simulator of a status of program execution by the execution unit.

A non-transitory computer-readable recording medium that records a control program for controlling an operation of a PLC simulator,

• the PLC simulator including a storage unit configured to be accessed by an external simulator that cyclically repeats processing based on a second cycle, and the PLC simulator cyclically repeating processing based on a first cycle,
• the control program causing the computer to execute:
• a step of causing the PLC simulator to execute a user program accompanying processing for inputting and outputting data to and from the storage unit of the PLC simulator;
• a step of causing the PLC simulator to detect that program execution in the external simulator is complete;
• a step of causing, after the user program is executed, the PLC simulator to suppress execution of a user program accompanying access to the storage unit, until the detection is performed;
• a step of causing the PLC simulator to communicate with the external simulator via a socket interface, in which the PLC similar receives a command from the external simulator for causing the PLC simulator to execute predetermined processing;
• and
• a step of causing the PLC simulator to execute processing in accordance with the command received using the socket interface,
• wherein the command includes a notification command for notifying the external simulator of a status of program execution by the PLC simulator, and
• wherein the detection is performed by the PLC simulator using the notification command.

A simulation method for a PLC simulation system,

• the PLC simulation system including a PLC simulator that cyclically repeats processing based on a first cycle, and an external simulator that cyclically repeats processing based on a second cycle, the PLC simulator including a storage unit for holding data for executing a program, the storage unit being configured to be accessed by the PLC simulator and the external simulator,
• the simulation method comprising:
• a step of the PLC simulator executing a program accompanying processing for inputting and outputting data to and from the storage unit;
• a step of the external simulator executing a program accompanying processing for inputting and outputting data to and from the storage unit;
• a step of at least one of the PLC simulator and the external simulator detecting that program execution in the other is complete;
• a step of at least one of the PLC simulator and the external simulator suppressing, after executing the program, execution of a program accompanying access to the storage unit, until the detection is performed;
• a step of the PLC simulator communicating with the external simulator via a socket interface, in which the PLC similar receives a command from the external simulator for causing the PLC simulator to execute predetermined processing;
• and
• a step of the execution unit executing processing in accordance with the command received using the socket interface,
• wherein the command includes a notification command for notifying the external simulator of a status of program execution by the first execution unit, and
• wherein the detection is performed by the PLC simulator using the notification command.