Programmable controller.

摘要

A write memory area (8a) and a reference memory area (8b) are employed in a user memory (l5) of a programmable controller (la), and a PID constant which has been arbitrarily changed based upon an externally inputted numeral value is written into the write memory area (8a), whereas the PID constant stored in the write memory area (8a) is transferred by a user program into the reference memory area (8b) within a time period which has been determined based on a time divisional control between a sequence calculation and a PID calculation. Then, the PID calculation is carried out with reference to the PID constant transferred to the reference memory area (8b). Also, when the numeral value is externally inputted into the user program within the time period determined by the time divisional control, the PID calculation is carried out and a calculation result is written into the write memory area (8a). Accordingly, the PID constant is arbitrarily changed without interrupting either operation of MPU (ll), or the PID calculation. <IMAGE>