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Dlloydev / QuickPID

A fast PID controller with multiple options. Various Integral anti-windup, Proportional, Derivative and timer control modes.
MIT License
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Spikes in PID output #33

Closed aaron-neal closed 2 years ago

aaron-neal commented 2 years ago

I am experiencing some odd spikes in the PID output. I am a bit of a novice on PID but, the image below doesn't seem like it should be right. Would fluctuations in my temperature readings cause these large spikes?

I am in the process of trying to figure out the cause, but thought I would post here in case there are any obvious known causes.

I appreciate this is not much to go on, just want to flag the issue while I investigate.

image

QuickPID myQuickPID(&_ioController.probes[0].average, &config.pidConfig[0].output, &config.pidConfig[0].set,  0, 0, 0, QuickPID::DIRECT);
myQuickPID.SetControllerDirection(QuickPID::DIRECT);
myQuickPID.SetOutputLimits(0,100);

Some logging of input, output and setpoint

PID IN:27.85, OUT: 66.06, SET: 30.00
PID IN:27.85, OUT: 67.79, SET: 30.00
PID IN:27.81, OUT: 69.84, SET: 30.00
PID IN:27.76, OUT: 71.92, SET: 30.00
PID IN:27.74, OUT: 74.00, SET: 30.00
PID IN:27.70, OUT: 76.11, SET: 30.00
PID IN:27.70, OUT: 77.94, SET: 30.00
PID IN:27.67, OUT: 80.11, SET: 30.00
PID IN:27.64, OUT: 82.05, SET: 30.00
PID IN:27.60, OUT: 84.26, SET: 30.00
PID IN:27.56, OUT: 100.00, SET: 30.00 <-
PID IN:27.56, OUT: 88.22, SET: 30.00
PID IN:27.53, OUT: 90.49, SET: 30.00
PID IN:27.51, OUT: 92.78, SET: 30.00
PID IN:27.48, OUT: 94.83, SET: 30.00
PID IN:27.45, OUT: 100.00, SET: 30.00 <-
PID IN:27.45, OUT: 98.94, SET: 30.00
PID IN:27.43, OUT: 100.00, SET: 30.00
PID IN:27.40, OUT: 100.00, SET: 30.00
PID IN:27.37, OUT: 100.00, SET: 30.00
PID IN:27.35, OUT: 100.00, SET: 30.00
PID IN:27.35, OUT: 100.00, SET: 30.00
aaron-neal commented 2 years ago

Sorry for wasting your time, after logging from the library direct, I can see that this is actually a different error. The library output is smooth, whilst my logging and display are not.

image