Communication control unit and communication control system

A communication control system comprising:

• a network;
• one or more control devices;
• and
• a communication control unit including:
• at least one of a hardware processor or circuitry programmed to effect:
• a control command calculator configured to calculate control commands for the control devices;
• a synchronizer configured to synchronize times of the communication control unit and the control devices according to a predetermined synchronization protocol, and to measure a communication delay between the communication control unit and each of the control devices;
• a communication delay storage configured to store the communication delay measured by the synchronizer;
• a control start time period collector configured to collect a control start time period of the control devices, the control start time period being a time period from a time at which an operation of a control execution in each of the control devices start until a time at which a significant operation of each of the control devices is actually made;
• a control start time period storage configured to store the control start time period collected by the control start time period collector;
• a cycle start time manager configured to determine, for each of the control devices, a time obtained by subtracting the control start time period stored in the control start time period storage from a start time of a common control execution cycle for the control devices as a cycle start time of each of the control devices;
• a cycle start time storage configured to store the cycle start time determined by the cycle start time manager;
• a communicator configured to communicate the control commands of the control command calculator, via the network;
• and
• a transmission time controller configured to calculate, for each of the control devices, a time obtained by subtracting the communication delay stored in the communication delay storage from the cycle start time stored in the cycle start time storage, and to communicate the control command of the control command calculator to the network by use of the communicator before an earliest time of calculated times within the common control execution cycle.

A communication control unit connected to plural control devices via a network and communicating with the control devices, the communication control unit comprising:

• at least one of a hardware processor or circuitry programmed to effect:
• a control command calculator configured to calculate control commands for the control devices;
• a synchronizer configured to synchronize times of the communication control unit and the control devices according to a predetermined synchronization protocol, and to measure a communication delay between the communication control unit and each of the control devices;
• a communication delay storage configured to store the communication delay measured by the synchronizer;
• a control start time period collector configured to collect, for each control device of the control devices, a control start time period which is a time period measured from a time at which an operation of a control execution is initially initiated within the each control device, until a time at which a resultant predetermined control operation effected by the each control device actually occurs responsive to the operation of the control execution;
• a control start time period storage configured to store the control start time period collected by the control start time period collector, for said each control device of the control devices;
• a cycle start time manager configured to determine, for each of the control devices, a time obtained by subtracting the control start time period stored in the control start time period storage from a start time of a common control execution cycle for the control devices as a cycle start time of each of the control devices;
• a cycle start time storage configured to store the cycle start time determined by the cycle start time manager;
• a communicator configured to communicate the control commands of the control command calculator, via the network;
• and
• a transmission time controller configured to calculate, for each of the control devices, a time obtained by subtracting the communication delay stored in the communication delay storage from the cycle start time stored in the cycle start time storage, and to communicate the control command of the control command calculator to the network by use of the communicator before an earliest time of calculated times within the common control execution cycle.