Technical Forum

Decentral Peripherie

PROFIBus End of Line Resistor Value

Thread Starter: henno2000   Started: 10/31/2008 10:01 AM   Replies: 2

« Previous thread Next thread »
Page 1 of 1 (3 items)
  10/31/2008, 10:01 AM
Joined 4/16/2007
Last visit: 12/23/2011
Posts: 177
Rating:
Rated: no ratings [0 out of 5 / rated 0 time(s)]. (0) 
Rated: no ratings [0 out of 5 / rated 0 time(s)]. (0) 
Hi,

On site we have some devices that are loacted at the end of the PROFIBus line, but the interface card does not have a 9 pin adapter, just some terminals.

At the minute everything is running OK, but am aware that a terminating resistor is normally enabled if the plugs are used.

I assume it would be wise to put an end of line resistor in the circuit?

If so, what value of resistance is to be used?

Regards,
henno2000
Top
  10/31/2008, 10:49 AM
Joined 3/21/2006
Last visit: 7/29/2014
Posts: 9868
Rating:
Rated: Outstanding [3.91 out of 5 / rated 1043 time(s)]. (1043) 
Rated: no ratings [0 out of 5 / rated 0 time(s)]. (0) 

Hi

 

May be you don't check carefully inside in devices? Did you read manufacture data sheed about this profibus connection? I'll give you one example. In ABB profibus modul is the same on the first look - just plug in red and green cables. But if you want to terminate the line must open the cover and switch on one button.

But any case about resistance you can find more info here: http://www.ccontrols.com/pdf/ExtV1N1.pdf

 

regards




=== Edited by UMENCHO @ 10/31/2008 10:50 AM [GMT ] ===


Top
  10/31/2008, 3:44 PM
Joined 9/27/2006
Last visit: 7/29/2014
Posts: 4719
Rating:
Rated: Excellent [4.21 out of 5 / rated 806 time(s)]. (806) 
Rated: Above avarage [3 out of 5 / rated 1 time(s)]. (1) 
Hello henno;
I strongly suggest you look into this Siemens offering:
6ES7972-0DA00-0AA0 SIMATIC DP, RS485 RESISTOR FOR TERMINATING PROFIBUS-/MPI-NETWORKS

Other manufacturers offer something similar (you can check on profibus.com, in the Products section); they take care of thetermination requirements, but also of grounding and isolation issues which resistors soldered to the lines will not handle. I have had some ugly experiences with clients trying to do it in-house and then blamed the fieldbus for the issues they had.

Hope this helps,
Daniel Chartier
Top
Page 1 of 1 (3 items)
Actions