PROGRAMMABLE CONTROLLER AND METHOD FOR SETTING AND DISPLAYING ITS INTERNAL INFORMATION

PURPOSE:To set the upper limit of a set value without depending on the change of a sequence program and to facilitate setting/management by registering the upper/lower limits of the set value of an internal device into a memory and judging whether the inputted set value is within the upper/lower limits or not. CONSTITUTION:A judgement means by upper/lower limit value memories 202 and 802 and CPU 3201 and 3301 is selectively provided in a peripheral unit 101 or a PC main body 601. The upper/lower limits of the set value for an internal device are registered into the upper/lower limit value memories 202 and 802. Respective CPU 3201 and 3301 judge whether an input value (set value) by an input part 3107 or an input/output part 3304 is within the upper/lower limits stored in the respective upper/lower limit value memories 202 and 802 or not. CPU 3201 and 3301 update the set points which are previously stored in RAM 3202 and 3302 by the set value being the input value based on intra- upper/lower limit value judgment. Thus, the setting/management of the set values and the upper/lower limit vaues of a timer and a counter can easily be executed without depending on the change of the sequence program.