OT-Powerflex question

I hope someone can answer this even though it is not a plc question. Is it possible to take a powerflex drive, set the speed from the front panel, then have a 4-20ma signal that would come from a dancer into the drive and use that to trim the speed that the drive is running either up or down by a certain percentage.
I tried calling ab tech support, but was not aware of the fact that you have to have a seperate tech support agreements for drives, it appears my tech support was only for plc and hmi panels, so tech support was not able to answer my question, put me on hold and after 23 minutes, i just gave up and figured I would try to post here.

thanks

Which PF Drive you are using because the options/functionality will very from drive family to family? I am guessing that you could set the speed from the HIM or Pot and then have a digital input programed to set the speed reference to the AI once the DI gets the signal.


HTH

Edit...Just looked up the PF 40 and DigitalIn param A051 could be set to 14 which sets the drive to 4-20mA Freq ref. So I am going to assume that if you are using a 40 or above you could do this.
It doesn't look like the PF 4 can do this but the PDF locked up on me when looking.

The Powerflex 4 manual shows the same thing that BobO was suggesting but I don't think it will do what you want. The input suggested by BobO would transfer ALL speed control to the 4-20 ma input. It won't just trim about a speed already set by the front panel.

Bernie is correct. What you want is the ability to use the dancer as a +/- trim against the main speed reference from the keypad.

I suspect that some of the highest level PF drives can do that but certainly not the PF4 or even the PF40.

We need to know what model PF you've got

A kludge is to set min speed (P34) and max speed (P35) to bracket the lowest and highest speeds you want. The 4-20 ma will then operate between those limits (4ma = Min, 20ma = max).

Sorry..I didn't read in detail about trimming the speed.
My bad, sorry for the poor advice.

It is a powerflex 40, but not sure the exact model or part number, will not actually know until Monday when I get there.
If not, going to try and convince the boss to let me use a basic micrologix 1200 and a analog card. There is already a tilt sensor that gives a 4-20ma signal.

According to the manual, the PF40 has a PID mode called Trim control in which the PID loop is used to trim the main speed reference. You would have to use both the voltage and the mA analog inputs to get the main speed reference and the dancer signal into the drive, or send the main reference to P038 via a ommunication port.

Look in the manual Appendix F, and also in chapter 1- page 15 at the wiring footnotes:

(2) 0-10V In and 4-20mA In are distinct input channels and may be connected simultaneously.
Inputs may be used independently for speed control or jointly when operating in PID mode.

Click to expand...

Thanks, OkiePC, for filling in on this. I know just enough about the PowerFlex line to be dangerous so your background with them is most helpful.

Thanks
great info, always good to hear how someone else may have done something, opens you up for new ideas.