PID Control Ladder Logic

[pirate 0]

I have an analog signal which I want to use to control 3 fans. In essence the fans will be brought in one by one the further away from the setpoint the analog signal gets. I think this is PI. Does anyone have any ladder that they might have used before for this sort of problem or similar. At the moment I stagger the outputs using timers and one set point. It works but not quite perfectly I'm sure there is a better way.

[michel 0]

Hi, if the fans are controlled as "on or off" there's not much use to use accurate PID controlling for that. Just watch your analog signal and add another fan according to the value. For example: Fan1 = AD > 500 Fan2 = AD > 750 Fan3 = AD > 1000 Would that be sufficient? Michel