profibus vs hardwired limit switches

[Lc85]

We are supplying an auma actuator and the client has said they want to use profibus. They have came back and said that for open and closed position a limit switch is required. Am I not right in saying that with profibus hardwired limit switches are not applicable? or would you still want to hardwire?

Thanks

 

[ScottyUK]

Ask the client what they are using the switch for. Maybe it isn't going to DCS - perhaps the switches drive local indicators or provide an interlock to a process drive, or something similar?

 

[mikekilroy]

Am I not right in saying that with profibus hardwired limit switches are not applicable?

yes, I would say you are ot correct. Profibus is simply a communications 'language' to tell something to do something. It has nothing to do with absolute open or closed position. for that you need some kind of absolute feedback; either an absolute encoder of some kind or limit sw;s as your customer is telling you.

 

[mikekilroy]

darn no edit button. shud have read:

yes, I would say you are NOT correct.

 

[hydroman247]

Are you all trying to fit as many double negatives in your posts as possible!

 

[djs]

It is my experience that electrical actuators, when configured with a field bus interface (Profibus, AS-Bus etc) generally do not provide hardwired limit switches. The open/close and position status is sent over the field bus. Perhaps they are requesting the fully open/close position status be sent over the Profibus?