How do I write a VI to force continuous voltage output from a power supply for a temperature ramp program?

[BoBeall80]

I have a temperature ramp program made (attached below), however, the voltage output on the power supply is oscillating as the ramp proceeds, resulting in the sample temperature falling below the theoretical temperature. This is seen in the picture as the the plotting of the actual temperature in white. I don't know whether the problem is with the PID controls or in some other part of the block diagram. If someone could possibly help correct this problem, I would be very thankful.

Best Regards,

Bo

[KHartley]

Bo,

Could you maybe post some tests of your PID algorithm and explain expected results for range of inputs? I'm assume you are controlling an oven type of device where the longer it takes to heat up the faster you want the voltage to increase. Also can you make sure that the relationship of the voltage at the power supply is actually generating the temperatures you desire? Are you maybe overloading your power supply? By that exponential decay I would assume that it has to do with the PID controls or possibly the heating element turned off.