ABB AC Drive - Model ACS550

[toastedhead]

I want to run this unit through a PLC which isnt the problem. One thing I want to do is be able to control the motor speed manually with a pot through the PLC. Does anyone know which input this is on the the ACS550 drive?

 

[DickDV]

OK, but, is both the manual and automatic speed control going thru the PLC or only the automatic with the manual being a separate speed pot operating directly on the drive?

 

[toastedhead]

Hmmm,I wouldnt think you could run them NOT through the PLC could you? Would there be conflicting inputs? That would depend on the macro I chose wouldnt it.

I suppose it doesnt really matter to me. Whichever route is the easiest.

 

[jraef]

A typical design philosophy would be to have the "manual" speed control input go directly to the VFD as an alternate speed command reference source. That way, if you need to do troubleshooting later and want to know if a problem is in the VFD response or the PLC speed reference command, you can resort to the pot as a direct speed reference without concern for what effect the PLC is having on it.

 

[DickDV]

The ABB Standard macro, for example, looks for its only speed input on AI1 by default. That could come from a PLC which combines and switches multiple speed commands into a single signal for the drive.

Or, you could choose the Hand/Auto macro which looks for a speed command on AI1 when in the hand mode and on AI2 when in the Auto mode. If you connect a simple pot to AI1 and your PLC to AI2, you will have one or the other depending on the switch on DI3.

So, its up to you. What do you want/need?

 

[toastedhead]

I think I like the Hand/Auto Macro. I initially didnt choose it because it appeared as if it wouldve been limited or I simply forgot about it.

So really, I'll just need to wire a POT to it? It cant be that easy - it never is for me.

 

[niallnz]

If you want simple put an extension cord on the removable drive key pad and run the drive in local control.

 

[DickDV]

Keep in mind that, with the Hand/Auto macro, as long as you have no connection between +24v and DI3, the drive will look at AI1 for speed (that would be your pot) and Start/Stop on DI1.

If you close the connection to DI3, then the speed signal is on AI2 and Start/Stop is on DI6. That can be configured differently but the above is the default setup.