Profi-BUS & Earthing Cable?

Dear Fellow PLC-Users,

Do any of you know something about; running an earthing cable together with the Profi-BUS?

If so:
1) What size cable?
2) Should it be shielded?
3) More info on this subject? Is it necessary?
4) How should it be connected?


Thanks for your support in this matter.
-JADT

Hi JADT

I think most of your questions should be answered in the Profibus Organisation's Installation Handbook. This gives very detailed instructions about what is and what isn't permissible in a Profibus network.
Try http://www.profibus.org, follow the "Downloads" link and take it from there.

Earthing is one of Profibus' big care-abouts. Get it right and the system will work for ever. Get it wrong and you'll have faults, spurious faults, multiple faults, transient faults etc. Since electrically Profibus is RS485, every node on the network needs to be earthed, and at the same earth potential.

Regards

Ken

Hello J.A.;

I have worked for many years with Profibus, and have never encountered the parallel laying of an earthing cable in any installation.
Although PI is very clear on the requirements for equipotential bonding (must be done at every Profibus node) and functionnal earth (part of the overall plant design), this is not part of the Profibus standard. If basic electrical installations are adequate 9as per standards) then all you need is the 3 point caonnections (A, B, Shield) that you can use on the different types of approved Profibus connections ond cables).
For more information, I can suggest you look for the manual "Profibus Installation Guide for Cabling and Assembly" from PI (Guideline_Assembling_8022_v106_May06.pdf).
Hope this helps,
Daniel Chartier

Thanks for the quick reply guys. I'll jump straight away into the Profi-BUS manual.

Regards
Augusto