PROGRAMMABLE CONTROLLER SYSTEM

摘要

In order to guarantee the temporal reliability of communication data in a programmable controller system even when the computation period of controller units is greater than the period of communication between controller units, a CPU (11) of a transmission-side controller unit (10A) generates communication data in a computation period and generates a number of transmission unit data with the number being equal to or less than a value obtained by dividing the generated communication data and by dividing the computation period by the communication period (step S1). A DMA controller sequentially transmits each of the multiple transmission units of data to transmission-use communication memories (15a, 15b) in the communication interval (steps S2, S4), and at a reception-side controller unit (10B), in a communication interval, the DMA controller sequentially reads (steps S5, S7) the multiple transmission units of data transmitted (steps S3, S6) sequentially to reception-use communication memories (16a, 16b).