PROFIBUS Coupler/terminals

Hello experts! I am looking for the best way to terminate a PROFIBUS cable coming into a cabinet. I want to terminate our internal line to a terminal/coupler in such way that the client does not have to go through our entire cabinet with his incoming line. I would like a simple/small unpowered solution. Does anyone have any pointers?

Thank you all!

The Profibus connectors that I've used in the past (from Siemens) have terminating resistors built in, if that's what you mean.

If you want to join two segments, I think you need a profibus repeater, but I think those need to be powered to work.

I was hoping for something like the plug, you can have two leads coming in, but instead of it having the SUB D, I just want to join the two cables. It is really weird to me that there doesn't seem to be anything that simple .

Profibus needs biasing with +5VDC power. D9-Connector takes this +5vdc from field defice or PLC.
Siemens and other manufactures have so called active profibus terminators.
https://cache.industry.siemens.com/.../att_111899/v1/3B_812_6727-10a_Terminator.pdf

Simplest is couple resistors and +5VDC supply

That would be overkill here. I have a PLC in the top of my cabinet, cables (generally) come in through the bottom. In the past, the client just runs the profibus cable through our cabinet directly to the PLC, but I don't like this. For one they over our termination strip in the bottom and more often than not, they don't even try to run the cable through the ducts.

I want to have some kind of terminal block next to the rest of my terminals to allow the client to connect to.

Attached photo is an example of how it could be done (not by us, I pulled it of a LINKED-IN group), but I expect this to fail sooner or later.

I don't see any reason why you could not use terminal block. Only if you are worried of mechanical stress for cable.

You can put D9 on Din-rail mount, even normal D9 connector connected to short profibus cable can work. On PLC side you have Profibus connector with terminator selected to On.

Prices vary:

http://www.advantech.com/products/gf-5aiq/adam-3909/mod_983a5a19-3710-4d3a-a2d0-8b34072c31b3
https://www.google.fi/search?q=d9+connector+din+rail&client=firefox-b&biw=1920&bih=946&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjHv5f5zuDRAhUGDSwKHUXNBYEQ_AUICCgB#tbm=isch&q=d9-connector+din+rail&imgrc=Nmtw_54gHMzFeM%3A

Just worried about interference. The picture above shows a considerable length not shielded.

I will check out those D9 connectors. Thanks!

On picture which you posted is A and B signal wires, there is also shield wire (concentric shield wire) connected to 3th terminal and covered by green tube.
Interference is not problem and you can peel insulation shortly before terminals.

Profibus needs good earthing, you can connect shields to technical earth.
If you use D9, connect D9 metal body to earth. At least terminal block connection have good earth connection

http://www.plctalk.net/qanda/showthread.php?t=44710

There is a reason why profibus cables are supposed to be terminated in the connectors. Every transition in a profibus cable such as terminals introduces reflections and degrades the signal quality. Not by much, but for the higher speeds it can be an issue, for 1.5Mbps if it is a complex network (many nodes, many segments, ..). For 12Mbps you can forget it.
The way the screen is connected in the previous picture is also a total no-go.

I dont understand why you cant allow the client to attach to the profibus connector even if that means he has to go through your wire ducts. What is the problem with that ? Wire ducts are supposed to facilitate easy installation of cables and wires, not to be an untouchable barrier.

Also, be sure to have proper screen clamps for all screened cables, using regular terminals and bundling the screen together plus crimpflex so it "looks nice" does not mean it is the proper way.
As I see it, there is no excuse for not doing these things to code.

If it is absolutely unacceptable to have the client installing the profibus cable in your wire duct, then you could use a repeater at the bottom of your panel, but that is overkill IMO.

Active terminator cost around 70-100, but is maybe overkill and OP didn't want to use it.
Phoenix have Plugtrab surge protector for profibus (PT 3-PB-ST). Plugtrab base have three screw terminals on both side for cable. Connection is same than on picture of three normal screw terminals. Thinked that it will not make much difference because of that.

What isn't sayed clearly is that also Phoenix surge protector will cut speeds to 12Mbps.

Page 7 on PDF: http://www.can-think.com.tw/ezportal/hyfiles/info/193_file226.pdf

Hopefully we get rid of RS485 and speed of 10mbps on next 40years

Going to profinet isn't allways easy either. Profinet have own protocols and if you have non-Siemens management switch, this data won't go thru with normal settings.

boneless said:

Hello experts! I am looking for the best way to terminate a PROFIBUS cable coming into a cabinet. I want to terminate our internal line to a terminal/coupler in such way that the client does not have to go through our entire cabinet with his incoming line. I would like a simple/small unpowered solution. Does anyone have any pointers?

Thank you all!

Click to expand...

Look at this from ABB

http://new.abb.com/products/measure...ss/profibus/profibus-junctions-and-connectors

https://library.e.abb.com/public/06edcccf4897f634c1257b0c00547c8e/63_644se.pdf