Control processor for user setting a change prohibition period during which a program change command will not be executed until the lapse of that period

摘要

A programmable logic controller for executing a control process in a controlled apparatus in accordance with execution of a user program includes a flag set section for setting a change prohibition period therein about the user program stored in a user program memory, and a control process section responsive to receipt of a program change command in the change prohibition period set in the flag set section for suspending a program change process but executing the program change process after the lapse of the change prohibition period.