CPU PLC CPU UNIT TARGET UNIT AND PLC SYSTEM

摘要

A first system bus input / output circuit unit 11 for input / output of a signal, an extended function control circuit unit 12 for communicating with an extended function circuit unit 22 provided in the target unit 3, (13) for switching the extension function control circuit part (12) to be connected to the first signal line (B1) included in the system bus (B), and the extended function control circuit part (12) The switching unit 13 may be a CPU unit that allows the extended function control circuit unit 12 and the first signal line B1 to be connected to each other when communication is performed with the extended function circuit unit 22 provided in the target unit 3 to provide. In the configuration in which the extension function part shares the same signal line with other components, even if the signal changes due to the influence of the external environment, the extension function part and other components can communicate without confusing the signal.