PROGRAMMABLE CONTROLLER

PURPOSE:To confirm the state of various devices at an optical moment and the state of various input-output data when a CPU processes information from the outside, by updating and storing data when the data are transferred from the 1st and 2nd storage means because the 3rd storage means receives a state holding instruction. CONSTITUTION:When a state holding instruction is read out while a user program is successively executed, data respectively stored in the memory 5 and data storing memory 7 of each device are read out and transferred to and stored in a state holding memory 9. However, since the storing contents of the memories 5 and 7 are transferred to the state holding memory 9 through an operation processing section 3 when the state holding instruction is read out, the content of the memory 9 is rewritten by the transferred storing contents. Therefore, the period during which the data are held b the state holding memory 9 becomes the period from the moment when the operation processing section3 reads out the first state holding instruction set in the user program to another moment just before the next state holding instruction is read out.