The S7-200 PID control is very stable; what’s the issue with the output value suddenly reaching 32,000 from time to time?
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Dear teachers, I recently created a flow control loop using the PID wizard of the S7-200. The proportional-integral parameters are also set stably, but occasionally the control loop output suddenly reaches its maximum value of 32,000, causing fluctuations in the control loop. The curves obtained through the PID tuning panel are as follows: http://bbs.hcbbs.com/forum.php?mod=image&aid=1297318&size=300x300&key=c4c5e56ba467dd31&nocache=yes&type=fixnone http://bbs.hcbbs.com/forum.php?mod=image&aid=1297319&size=300x300&key=8f0cc44e3148185d&nocache=yes&type=fixnone. I tried creating a PID using the wizard again, but it still didn’t work; I checked several times, and no other programs are invoking AQW0! I really can’t find the reason; please give me some guidance! http://bbs.hcbbs.com/forum.php?mod=image&aid=1297321&size=300x300&key=3a0f8b204990e949&nocache=yes&type=fixnone
What if the PID is set to manual?
As mentioned above, switch it to manual mode and see if the output remains the same； Otherwise, there is a problem with the PV input; in automatic mode, abnormalities in the PV can cause changes in output control.
Check to see if there are any disconnection signals from time to time.
It’s very stable once I switch to manual mode; I’ve been using manual mode ever since!
I don’t understand the disconnect signal you’re talking about! Did the signal just disappear?
Some of Siemens’ AI modules have wire-disconnection detection; if the AI signal is not transmitted properly or there is a problem with the instrument, a brief disconnection signal may occur, affecting the PV input and thus leading to abnormal outputs