Process synchronization control system and process synchronization control method

A process synchronization control system for synchronizing a process among a plurality of redundant devices, each of the plurality of devices comprising:

• an input unit configured to receive a synchronization signal from the other device;
• an output unit configured to output the synchronization signal to the other device;
• a synchronization process unit connected to the input unit and the output unit and configured to execute a synchronization process of synchronizing a process with the other device;
• a process execution timer configured to be used for executing a process in the device;
• and
• a waiting time measurement timer configured to measure a waiting time in the synchronization process,
• wherein the synchronization process unit is configured to execute:
• a synchronization signal output process of outputting the synchronization signal to the other device through the output unit at the start of the synchronization process;
• a synchronization signal input process of waiting for the synchronization signal input from the other device through the input unit until a predetermined waiting time by the waiting time measurement timer elapses;
• and
• a timer synchronization process of synchronizing the process execution timer if the synchronization signal of the other device is input after the elapse of the waiting time.