Control system, control device, and non-transitory computer-readable recording medium recording program

A control device that controls a target, comprising:

• a part for communicating with a network that communicably connects a plurality of the control devices in a network configuration, wherein the control devices that are connectable to the network configuration include a first control device that is in operation and a second control device that is different from the first control device;
• a timer that manages time having an accuracy;
• a communicator for transmitting a control command to the target corresponding to the control device with the time managed by the timer as a reference;
• a timer synchronizer for, when the network configuration is changed, time-synchronizing, among timers of the plurality of respective control devices connected to the network after the change, other timers with a timer having a higher time accuracy than time accuracies of any of the other timers, wherein the change of the network configuration includes that the second control device is added to the network to which the first control device in operation is connected;
• and
• a message communicator for performing communication of a message having an accuracy of the timer of the own device,
• wherein the timer synchronizer compares the accuracy of the time in the message received from another control device with the accuracy of the timer of the own device, and selects the timer having the higher time accuracy on the basis of a comparison result.

A non-transitory computer-readable recording medium, recording a program causing a computer to execute a method of synchronizing time with a control device that controls a target, the control device comprising:

• a part for communicating with a network that communicably connects a plurality of the control devices in a network configuration, wherein the control devices that are connectable to the network configuration include a first control device that is in operation and a second control device that is different from the first control device;
• a timer that manages time having an accuracy;
• a communicator for transmitting a control command to the target corresponding to the control device with the time managed by the timer as a reference,
• the method comprising:
• a step of performing communication of a message having an accuracy of the timer of the own device;
• a step of, when the network configuration is changed, comparing the accuracy of the time in the message received from another control device with the accuracy of the timer of the own device, and detecting a timer having a higher time accuracy than time accuracies of any of other timers among timers of the plurality of respective control devices connected to the network after the change on the basis of a comparison result, wherein the change of the network configuration includes that the second control device is added to the network to which the first control device in operation is connected;
• and
• a step of time-synchronizing the other timers with the timer having the higher time accuracy.