INTER-PLC COMMUNICATION DATA COMPLEMENTARY DEVICE, INTER-PLC COMMUNICATION DATA COMPLEMENTARY METHOD, AND INTER-PLC COMMUNICATION DATA COMPLEMENTARY PROGRAM

摘要

PROBLEM TO BE SOLVED: To complement a data value to be received in a current period even when a delay accompanied with omission of data updating occurs due to a communication network in which constant periodicity is not secured.SOLUTION: A data complementary device 2 of a PLC 1 is connected to a PLC 30 via a communication network 20 and is activated with the same control sampling period as that of the PLC 30. A storage section 4 receives data in which a counter value 34 being transmitted from the PLC 30 for each control sampling period and updated for each period is associated with a data value 33, and stores the data. A comparison section 5 determines a delay to exist when the counter value of the data of a current period stored in the storage section 4 for each control sampling period is the same as the counter value of the data of a period preceding by one period. When the delay is determined to exist, a complementary section 3 estimates the data value of the data to be received in the current period and complements the data value estimated based on a rate of change between the data value of the data of a period preceding by two periods and the data value of the data of the period preceding by one period stored in the storage section 4.SELECTED DRAWING: Figure 1