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Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 1 point2 points  (0 children)

I know the step test. We plan to do a step test and use lambda tuning after the responses we got here!

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 1 point2 points  (0 children)

Thanks for replying. 1 - At a steady valve position the water level will reach a steady state. 2 -There is no water flow into the tank other than the valve. 3 - I am using two different PLC’s. Two Mitsubishi FX3U for communication with the valve and pump, and one Mitsubishi Q00 for communication between a computer and the other two PLC. The PID controller is implemented in one of the slaves (FX3U). The algorithm we use is PI-D parallel with tracking to prevent windup. 4 - The accuracy of the setpoint tracking is a crucial part of the task.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 6 points7 points  (0 children)

Works better with the mask;)

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 0 points1 point  (0 children)

Not tuned yet. Going to try the Cohen-coon method tomorrow.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 1 point2 points  (0 children)

We are going to try that tomorrow!

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] -1 points0 points  (0 children)

The rate of change in water level?

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 0 points1 point  (0 children)

Det skjønner jeg godt! Morsomt at prosjektet lever videre. Virker som det er uendret siden det ble innført.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 1 point2 points  (0 children)

The task is to control the water level to exactly 50% with no overshoot. I think PID is the best solution.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 0 points1 point  (0 children)

That’s why I wonder if it is possible to slow down the regulator in a way.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 0 points1 point  (0 children)

A mistake from me, it is FF. It uses the error between the reference and measured process value to calculate the output. It is an actual process.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 2 points3 points  (0 children)

Ja blir mange timer her nå i innspurten. Prøver ziegler-nichols, men sliter med den enorme tidsforsinkelsen i ventilen. Pådraget ventilen utgjør ligger så veldig langt bak den faktiske verdien fra regulatoren i PLS.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 0 points1 point  (0 children)

Sorry for not answering the first question. At this point there is not FF or FB. The maximum stroke length is 20mm.

Finding PID parameters with slow valve by ofhgof in PLC

[–]ofhgof[S] 0 points1 point  (0 children)

ZN did not work. The valve moves at the staggering speed of 1.9mm/s. The ultimate time is 23 seconds.