Control system and method for on-line editing of user program

摘要

A control system includes a programmable controller having a CPU unit that carries out cyclic operations of processes. An additional temporary user memory is provided in addition to a regular user memory. When an on-line editing of a user program is to be carried out, the program is stored in both memories and the program stored in the temporary memory is called by an instruction execution engine to be executed. After the on-line editing is completed on the user program stored in the user memory, the program execution is based on the edited user program stored in the user memory.