PLC SIMULATION SYSTEM, PLC SIMULATOR, RECORDING MEDIUM, AND SIMULATION METHOD

摘要

In a PLC simulation system (10), at least one of a PLC simulator (2) and an external simulator (4) executes processing while checking the status of program execution in the other. For example, the PLC simulator (2) provides a socket interface, and operates upon receiving various commands from the external simulator (4). The external simulator (4) checks, using a command, whether processing for a program is being executed or the execution is finished in the PLC simulator (2). The external simulator (4) checks the status of operation of the program in the PLC simulator (2), and executes processing accompanying writing to a PLC memory (205b) or the like, in a case where contention of access to the PLC memory (205b) does not occur.