CPU OF PLC, SYSTEM PROGRAM FOR PLC, AND RECORDING MEDIUM STORING SYSTEM PROGRAM FOR PLC

摘要

In this invention, a microprocessor controls at least one of a first communication circuit and a second communication circuit such that the following are executed in parallel: a first input/output process including a process that outputs output data from a first transfer buffer to a first instrument of a PLC system bus via the first communication circuit, and a process that inputs input data from the first instrument to the first transfer buffer via the first communication circuit; and a second input/output process including a process that outputs output data from a second transfer buffer to a second instrument of a field network via the second communication circuit, and a process that inputs input data from the second instrument to the second transfer buffer via the second communication circuit.