Is there someone that knows if there any studies on "time-proportioning control"?

In particular i need to know:
- Is there any teorical law (non pratical) to choose time-cycle?
- How time cycle affect the controller perfomance (I use PID)?

I need need urgently those informations ... PLEASE, HELP ME!!!
Raffaele

 

Yes, the rule is that the cycle time must be shorter than 1/12 the Integral TC. There are many caviats to this, however. Some TP algorithms are constant cycle time at 50% duty cycle but corrupt to a longer cycle time as
you stray from 50%. Some widen immediately while others widen once you hit a minimum ON time or minimum OFF time setting. This implies that the loop will begin to oscillate once you stray from 50%.

There are other things to consider. In principle, the cycle time should be as short as the actuator will allow. If you are using a solid state contactor then use 100 msec as the cycle time. For Mercury contactors run around 5 seconds and for mechanical contactors the defaults usually run 20 second.

Any more detail needed, contact me at [email protected]

Cheers,
Mitch

 

Check-out "www.watlow.com":http://www.watlow.com . They have PDF documents for download.

Anthony Kerstens P.Eng.

 

This denomiation has no meaning. It comes out from some half smart cat to lose the user. They all revert to PID. It might bug the
implementation.