To improve integrity of time synchronization, a node in the safety rated system takes steps to ensure the time to which it is synchronized has not become corrupted. The node receives a synchronize request message from an adjacent network device, which includes the master time, and the node generates an offset value corresponding to a difference between a local time and the master time. The node stores the offset time into a safety memory to ensure that the offset value has data integrity and does not become corrupted. The node performs periodic skew detection between two devices to verify that the clocks remain synchronized. In addition, the node performs a local drift detection to detect if the frequency of the local oscillator on which the local clock value is based begins to change.

A control method and a control system using the same as are provided. The method includes: extracting a corresponding component data from a component data stream based on an application protocol registered by each of a plurality of applications and encapsulating a corresponding application data packet for the application in response to receiving the component data stream in a current control period; transmitting the corresponding application data packet to each of the applications; obtaining control data reported by each of the applications according to data reporting timing corresponding to the application; and generating a component control instruction for controlling each of the components according to the control data reported by each of the applications in the current control period and the application protocol registered by the application. In this manner, the orderly control of a smart devices within a limited control period can be achieved.

A controller includes circuitry configured to: synchronize a master clock with an external global clock and set a master time based on the master clock; synchronize a controller clock with the master clock and perform time synchronization to synchronize a controller time based on the controller clock with the master time; transmit controller time data indicating the synchronized controller time to at least one local device; set a plurality of time windows corresponding to a plurality of clock cycles of a clock signal for the time synchronization; determine whether one clock cycle of the plurality of clock cycles has started within one time window of the plurality of time windows, the one time window corresponding to the one clock cycle; and suspend the time synchronization corresponding to the one clock cycle, in response to determining that the one clock cycle has not started within the one time window.

A controller includes circuitry configured to: synchronize a master clock with an external global clock and set a master time based on the master clock; synchronize a controller clock with the master clock and perform time synchronization to synchronize a controller time based on the controller clock with the master time; transmit controller time data indicating the synchronized controller time to at least one local device; set a plurality of time windows corresponding to a plurality of clock cycles of a clock signal for the time synchronization; determine whether one clock cycle of the plurality of clock cycles has started within one time window of the plurality of time windows, the one time window corresponding to the one clock cycle; and suspend the time synchronization corresponding to the one clock cycle, in response to determining that the one clock cycle has not started within the one time window.

A control device includes a first processor that acquires a synchronization signal that is generated every first period, and a second processor that generates a second period that is obtained by dividing the first period by n (n≥1), generates a control signal, using a timer, every third period that is obtained by dividing the second period by m (m≥2), where at least one of a plurality of control signals generated in the first period is a control signal that should be synchronous with the synchronization signal, and in a case where occurrence of an error between timings of the synchronization signal and the control signal that should be synchronous with the synchronization signal is detected, the second processor corrects the error by temporarily changing a width of the timer that is to be started at next and later times.

The machine control system includes: a machine configured to execute a motion according to a machine command; a controller server configured to control the machine; and a communication server. The controller server includes control circuitry configured to repeat operations according to a control cycle, the operations including: executing a motion program to generate the machine command for the machine; adding first cycle information designating a first use timing to the machine command; and transmitting the machine command including the first cycle information to the communication server. The machine includes a machine circuitry configured to repeat local operations for controlling the machine according to a local control cycle. The machine circuitry is further configured to: store the machine command received from the communication server; and call the stored machine command, based on the first cycle information added to the stored machine command, to use the machine command in the local control cycle corresponding to the first use timing.

To improve integrity of time synchronization, a node in the safety rated system takes steps to ensure the time to which it is synchronized has not become corrupted. The node receives a synchronize request message from an adjacent network device, which includes the master time, and the node generates an offset value corresponding to a difference between a local time and the master time. The node stores the offset time into a safety memory to ensure that the offset value has data integrity and does not become corrupted. The node performs periodic skew detection between two devices to verify that the clocks remain synchronized. In addition, the node performs a local drift detection to detect if the frequency of the local oscillator on which the local clock value is based begins to change.

A control device includes a first processor that acquires a synchronization signal that is generated every first period, and a second processor that generates a second period that is obtained by dividing the first period by n (n1), generates a control signal, using a timer, every third period that is obtained by dividing the second period by m (m2), where at least one of a plurality of control signals generated in the first period is a control signal that should be synchronous with the synchronization signal, and in a case where occurrence of an error between timings of the synchronization signal and the control signal that should be synchronous with the synchronization signal is detected, the second processor corrects the error by temporarily changing a width of the timer that is to be started at next and later times.

The control system includes a first controller, a second controller, and a third controller. The third controller includes a first communication module, a second communication module, and a control processing module configured to output a first operation command for operating the first controlled object to the first controller via the first communication module, configured to output a second operation command for operating the second controlled object to the second controller via the second communication module, configured to switch a mode between a normal control mode and a synchronous control mode, and configured to output, to the second controller via the second communication module, a command to decrease the second gain during at least part of a period of the synchronous control mode as compared with the normal control mode.

The machine control system includes: a machine configured to execute a motion according to a machine command; a controller server configured to control the machine; and a communication server. The controller server includes control circuitry configured to repeat operations according to a control cycle, the operations including: executing a motion program to generate the machine command for the machine; adding first cycle information designating a first use timing to the machine command; and transmitting the machine command including the first cycle information to the communication server. The machine includes a machine circuitry configured to repeat local operations for controlling the machine according to a local control cycle. The machine circuitry is further configured to: store the machine command received from the communication server; and call the stored machine command, based on the first cycle information added to the stored machine command, to use the machine command in the local control cycle corresponding to the first use timing.