Profibus cable connection unit?

Hello all,

I am looking for a working solution to connect 2 ends of a profibus cable together in the field, these 2 cables are inside a robot and simply need to connect together but allow all signal strength an clarity. Im pretty sure theres a siemens product on the market or a similar product from another company as i had a profibus training course not too long back but im buggered if i can find it in the handbook or in my notes. I know that this is not recommended practice over profibus but im sure it must be possible.

Any help would be greatly appreciated.

Cheers

BMW_APPRENTICE (who is no longer an apprentice but likes the name)

Hello BMW_APPRENTICE (who is no longer an apprentice but likes the name).

Just to be sure I get it right, the cable ends do not arrive at a Profibus station ? They just end there in the robot ?

If they end at a DP station, you daisy-chain the cable in a proper Profibus connector.

If the just end without there being a DP station:
Up to 1.5 Mbps, you can splice the cable any which way. Only be sure to get the screen connected well.
At 12Mbps Profibus is much more finicky. You may have to exchange the cable ends for a uninterrupted cable all the way.

Ah, not quite. The cables are going to profibus nodes, the break in the cable is in axis 1 of the robot and the break is to allow the removal of any axis other than axis 1 without having to break the cable. I believe the communication speed from the RC is 187.5KB/s. By daisy-chain in a proper profibus connector I assume you mean a normal plug thats not connected to anything, is this safe in a EX rated area and can this guaruntee signal quality if not plugged into an actual node?

Cheers

BMW_APPRENTICE

Now I dont get it.
You need to remove the other stations, not the robot you have mentioned ?
I think you should describe in more detail exactly what you need to achieve. A small diagram will be nice.

By daisy-chain in a proper profibus connector I assume you mean a normal plug thats not connected to anything,

Click to expand...

I mean a plug with two profibus cables entering the plug. Removing the connector will disconnect the directly attached station (obviously), but the rest of the Profibus network will remain unaffected. This only applies to a station in the middle of the daisy-chain, not in the ends.
Anyway, disregard all this until we have established exactly what the objective is.

Basically, we have a complete profibus network which runs from the RC through the robot communicating to all the resolvers on the motors to control position of movement (as far as im aware). If this was one complete cable in the event of a failure on one of the axis this would mean cutting the cable to remove the particular axis or disconnecting all of the other axis, removing the cable, and then once reattached rerouting the cable. To avoid this predicament we have broken pieces of profibus cable that are joined in the robot itself (currently by solder joints that have now failed). I am looking for a more robust solution to stop wear on these solder joints.
This brings me back to the original problem of some kind of junction box with a gland that allows me to ensure that the cable will not be pulled against the joint.

Hope this makes sense.

Cheers

BMW_APPRENTICE

So, the problem is that when one slave needs to be removed for repair, you currently cannot do that without physically cutting the cable, requiring splicing the cable, which has been done until now by soldering.

How many stations are there ?
Exactly how is the cable currently connected at each of these stations (resolvers or axis or whatever) ?
Again, a small diagram would do wonders to understand the whole thing.

ok so ive had a day at uni and ive had a think. What were trying to achieve here is an efficient way of connecting and disconnecting a cable when necessary. The problem we have at the moment is that the robot is moving, and whereas its not supposed to pull the cable it appears it is. This is putting stress on the joint of the cable. We currently have it in the configuration as you suggested with a plug with no node connected. The only problem with this is the space is tight and the cable is going 2 opposite directions, With the cable coming out of 2 connections very close to one another this is straining the plug and further strain is applied under movement. There is the option of a bracket to take the strain but i would prefer a more robuts connection box that meets the standard of profibus. I have added an image showing how the connections are currently. Its an extremely short run of 5 nodes and there is a break in the cable between 2 of these.

I hope this is starting to make some sense... maybe not.

Im just looking for a product that is capable of this really..... and if its something that should or shouldnt be done as best practice.

There is the option of a bracket to take the strain but i would prefer a more robuts connection box that meets the standard of profibus.

Click to expand...

I dont know if there is a "standardised Profibus way" of doing it, but a strain relief in the shape of clamps that hold the cable is the regular way with "normal" cable.
I dont like that you say that there is "strain" in the cable.
Even if flexible robot cables are used, the cable should not have any significant "pull" or "twist" when it moves through from one extreme to the other extreme position of the robot. There must be some slack to counter the greater part of any pulling or twisting of the cable.

I shall see if I can find some photos from some of our machines.

ok, strain is a bit rich in this instance. More like there is movement on the cable and as we only open the robot outer housing on a monthly/breakdown basis there is a certain amount of movement which goes on which moves the cable a certain amount. This amount of movement is fairly small (as the space it has to move in is small) but this brings in another area of possible failure on a system which is critical to the running of the facility. There is slack in the cable but inevitably movement can cause slight tensions in both directions against the 2 joints.

How about a Siemens 6ES7 158-0AD00-0XA0 "DP-DP Coupler" ?

Hi

Have you considered the M12 connector option. On the RC side have a female M12 and on the other a male these then screw into one antother to give an IP67 connection. There is also the option of mounting these on a bracket to provide more stability.

Hope this helps.

Cheers,

Scott
Tycon Automation Ltd.
www.tyconautomation.co.uk

Use an active terminator after the robot. This will properly terminate the network even if robot is not there. Or move cabling so robot is in the middle.

DP/DP coupler is not the correct method. That is used to share data between to seperate networks.

Hi bmw_apprentice,

To connect two ends of profibus cables you could use the following connectors:

* Femmale: TURCK Connector type BMWS8151-0/9

* Male: TURCK Connector type BMSWS8151-0/9
see also: http://www.turck-usa.com/Products/Networks/PROFIBUS-DP/Interconnection_Products/

* Terminating Resistor: TURCK Type RKSW45-TR or RSSW45-TR
see also: http://www.turck-usa.com/Products/Networks/PROFIBUS-DP/Network_Accessories/Terminating_Resistors.htm

I hope this is of any help for you

Thankyou for all your replies, i just thought id return and let you know what we ended up going with. It turned out to be something very similar to the TRUCK connectors, just made by siemens instead. If your interested the part numbers are:
- 6GK1905-0EA10
- 6GK1905-0EB10

Cheers guys