General-purpose functional circuit and general-purpose unit for programmable controller

A general-purpose unit for a programmable controller, comprising:

• an external connector which is configured to connect to an external appliance to be controlled;
• an interconnecting connector which is configured to connect to a CPU unit of the programmable controller;
• an arithmetic processor which transmits signals to and receives signals from the external appliance through the external connector, and performs a logical operation based on an external signal received from the external appliance so as to transmit to the CPU unit via the interconnecting connector a logical operation signal corresponding to a result of the logical operation, said arithmetic processor comprising:
• a volatile programmable logic device (PLD);
• and
• a non-volatile PLD that detects a malfunction in downloading data to the volatile PLD;
• and
• a housing which accommodates the arithmetic processor and having an outer surface, the external connector and the interconnecting connector being provided on the outer surface so as to be exposed,
• wherein the CPU unit includes a CPU that executes a sequence program.

A general-purpose functional circuit for a programmable controller, comprising:

• an external connector which is configured to connect to an external appliance to be controlled;
• an interconnecting connector which is configured to connect to a CPU unit of the programmable controller;
• an arithmetic processor which transmits signals to and receives signals from the external appliance through the external connector, and performs a logical operation based on an external signal received from the external appliance so as to transmit to the CPU unit via the interconnecting connector a logical operation signal corresponding to a result of the logical operation, said arithmetic processor comprising a gate array having a plurality of special functions;
• an extension substrate for expanding the special functions with additional special functions;
• and
• an extension connector which is connected to the extension substrate,
• wherein the CPU unit includes a CPU that executes a sequence program.