Hi I hope someone can help with this issue. I am trying to control temperature using the PID.vi. I’ve built a small model. The cooling element is from a computer fan and the heat source is a large power resistor. The PID output is feeding into a PWM.vi, which is being used to drive the cooling fan.Everything works accept when I raise the setpoint (temperature), the output from the PID.vi goes high. The fan kicks on and the temp drops even further. The same happens in reverse, when I drop the setpoint (temp) below the current (process variable) temp the output from the PID should start up the fan instead it justs sets it to zero output. In short my PID is trying to control a heating control loop when in actual fact I want it to control a cooling fan. How do I go about changing the PID output to reflect this?Any solutions or tips would be greatly appreciated
Hi, you need to work out if your process is direct or reverse acting. It sounds like it is reverse acting. You could try negating your gain kc. If that doesn't work post your code so we can take a look for you.
