Profibus networks and grounding

If you have several remote cabinets with profibus stations at a distance of about 100 m, do you take special precautions towards grounding to minimize problems with profibus communication?
The remote cabinets will take their power from the main cabinet, so a ground connectin cable will also arrive from the main cabinet in the remote cabinet. But normally the section of this ground connection is not big. Is there a minimum crosssection of the ground PE-cable that you should advise to avoid communication problems due to ground differences?
Thanks

This is how I would do it...

- separate TE-ground
- 10 mm2 grounding wire between cabinets
- profibus shield grounded into TE-ground (incoming and outgoing)

...but it's not so simple. If the communication baudrate is lower, the network can tolerate more disturbance. And is there a lot of electrical noise in the enviroment.

There is a lot of information on the profibus.com website.

Profibus.com

What is a TE ground??

10 mm is equivalent to .36 inches. Seems to be a large conductor to me.

Assuming cabinets are not enclosing large power equipment ie only communications I would bond them with a #10 or 12 green and then tie that to the main ground system. That way all cabinets are at same potential ie ground. Here in USA code will let you run a bond conductor without conduit although ideally it should be in conduit for better protection.

Dan Bentler

He means to say 10 mm² area, not 10 mm diameter.
"TE" is "Technical Earth" I think.
Now what is "#10" and "#12" ?

10mm2 = 8AWG.

Jesper, they use some weird wiring system over here, where the higher the number the smaller the cable ??

i.e. 10AWG=6mm and 12AWG=4mm.

I do believe they are crazy

I seem to remember reading that the politically correct size potential equalising cable between profibus boxes is 25mm2 I can't say that I have stuck to this and generally rely on the supply earth without any trouble to date. It isn't cost effective to be running 25mm2 cables.

About one year ago I posted here similar issue, but not got answer yet.

My question was see attachment.


However I worked around it and found out right decision. In parallel of each profibus span should be laid 16 mm2 green-yellow conductor.

This link is to Siemens manual 6GK1970-5CA20-0AA1 which is a detailed Profibus network installation guide.

Section C goes through earth bonding.

JesperMP said:

He means to say 10 mm² area, not 10 mm diameter.
"TE" is "Technical Earth" I think.
Now what is "#10" and "#12" ?

Click to expand...

JESPER
Thanks for catching me. I missed the square value 10mm2 and saw only 10mm.

I did take into account and tried to explain that I was using Yankee values ie #10 and 12 for conductor size. 10 and 12 are American Wire Guage values I believe (or some other "standard" we got from those crazy guys across the pond ie British you know the guys that drag the king around so they can use his thumb to measure an inch.

When they changed kings did they recalibrate the new kings thumb or just change the standard? Always wondered about that.
Dan Bentler