CCT Program Locks up PID to 0 or 100%

[integrator]

Hello,

In our CCT program we have a span block for OA reset. The result goes into our PID Setpoint. The output of the PID controls our valve. The PID is set as Direct Acting false.

What is happening, is that the PID runs for couple of days and then locks up to 0 or 100%. The Process Variable into the PID is from our boilers which change in temperature quite a bit.

Has anyone seen this before?


Thanks

[dx9100]

It could be the self-tunning has tuned itself crazy. Check the the PI parameters in the PID loop. You might find a very big I or a P with value of zero. Change it to manual tuning if you have to.

[freddy-b]

SUPERPRAC sucks too? It can't be!!!!!!!!!!