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PI Controller Reset function

Verfasst: Montag 27. März 2017, 15:18
von QMESAR
Hi All,

Please I need your help with the PI Controller,As shown in the attached sketch I have my set point signal and the feed back signal with the KP and KI parts the output goes into a limiter that sets me the max and minimum outputs for the controller.
This functions however my problem is how to reset the integrator ,my understanding from the help file is the reset pin reset the integrator and by adding a pulse generator to the RST pin with a rate at 1 sec I can see the output go higher and at 1 second fall back to the original value however in the real system this is a problem as the actuator would move to try and correct the error but when the integrator is resetted it falls back even with not correcting the error,I need the actuator to keep on moving to correct the error until max is reached and then stay there if the error remains or when the error get smaller and even 0 then the integrator should reset,

How can I achieve this in PL I appreciate all help highly

Kind Regards

Re: PI Controller Reset function

Verfasst: Dienstag 28. März 2017, 08:06
von abacom
This functions however my problem is how to reset the integrator
Simply pull down /RST to LOW once for reset, whenever necessary. That´s it.

Re: PI Controller Reset function

Verfasst: Dienstag 28. März 2017, 10:33
von QMESAR
abacom hat geschrieben:Simply pull down /RST to LOW once for reset, whenever necessary. That´s it.
Thank you for the reply , :D
This is not my problem how to reset it, I have done that by pulling the RST pin low and it works my question was how can I determine when the error is small and the integration should stop or be set to zero ,Do I calculate the error manually in front of the PI component with a math component ?

Re: PI Controller Reset function

Verfasst: Mittwoch 29. März 2017, 08:18
von abacom
??? So I don´t understand your request unfortunately. Sorry for that.

Re: PI Controller Reset function

Verfasst: Mittwoch 29. März 2017, 08:35
von tmm
Hi,

for example, do something like this........

Re: PI Controller Reset function

Verfasst: Mittwoch 29. März 2017, 08:51
von Mike D
since you use the limiter, have you already seen the properties of PI?
Make a double klick on PI.

Mike

P.S. please use punctuation marks and shorter sentences. So we could better understand you.

Re: PI Controller Reset function

Verfasst: Freitag 31. März 2017, 11:39
von QMESAR
Hi All.

tmm thank you for your PL project this helped me to do as per attached screen print,maybe not perfectly correct but it functions in real time operation and I can live with it for now on the machine

All that I asked was
(1)ideas for a method to determine when the error is small;this method should the reset / stop the integration of the PI or PID component
(2) It was clear that pulling the RST pin low the integration will stop or reset (This is clearly mentioned in the Help file)
(3) I do read the help file before wasting peoples time here in the forum