Hi All

I am new to this Profibus DP communication. I have 4 segments of Profibus DP spread all over the facility. I have a single channel Profibus DP Master Class 2 module. I want all these segments to end in this single channel module. (devices are just 23).

Please advise how can I connect these 4 segments into one single channel Profibus DP module?

What to use?
Repeaters or Couplers?
And how to use them also (a brief info will be very helpful to me)
Awaiting your comments.

Best Regards,

 

Difficult to say without knowing your actual plant layout.

One of the limitations will be the speed you are running the bus at which determines the maximum length of the network. I assume that you do not want to connect each segment together to create a single run from the furthest slave to the master? Also, in case you were not aware, the master can be in the middle of the network and does not have to be at the end.

A coupler connects a DP network to another network with a different Master, so you should probably be looking at repeaters which allow you to spur off the network and increase the distance if required.

I think there are limitations with the number of repeaters you can use but I can't remember. (Maybe 3 on one DP?)

Hope that helps

Tom

--
Tom Chubb
tomchubb [at] gmail.com

 

Thanks Tom for your reply

Plant layout? can I show that here? (if yes then how, as it is a JPEG)

I got your point regarding the master. We can place master anywhere in the segment. Right?

I got the concept of repeaters and couplers. I was confused in couplers. Thanks for that also.

The max segment length is around 850 meters
One segment length is around 750 meters
one is just 130 meters
and the other is about 500 meters
(these are exaggerated measurements)

The overall segment length in star topology is about 2.4km and I have 4kms of profibus cable available.

The task is to measure flow of Water at different locations so I think speed can be reduced and we may go for about 800-1000 meters per segment.

I think spurring off network is quite possible as I can see from a rough sketch.

Please guide me how to share the sketch on this forum.

Thanks and Best Regards,
Jawwad

<b>Moderator's note:</b> Your friendly local moderator here. You cannot post attachments to the forum. My recommendation is that you post it to one of the free download sites and post a message that has the url.

 

> Please advise how can I connect these 4 segments into one single channel Profibus DP module?

Connect the master to a backbone segment and all other segment by a repeater to the backbone.

That's all ..

Best Regards
Armin Steinhoff

 

Thanks Mod!
I am using that service now =)

Thank you Armin for your suggestion.

Tom, please see the map

http://i43.tinypic.com/2ujqt10.jpg


Armin, Please tell me if this layout is according to your suggestion.

I connected Master to backbone segment, and then attached 3 repeaters to the backbone segment and other devices after repeaters to the backbone.
http://i40.tinypic.com/cja8l.jpg

Please advise if I got it correct or not. If not please correct me.

I respect both of you and really grateful for your kind concern =)

Awaiting your response =)

Many Thanks and Best Regards,

Jawwad

 

I am still waiting for your reply please
If someone else can also tell then please guide and oblige.

Thank you for reading my thread

 

Jawwad,

The main back-bone should have a start and end point as one long daisy-chain. From each repeater, you can branch off to a new segment with it's own start/end point as one daisy-chain.

So in the image you have shown, the cabling for Segment 1 would need to be part of the back-bone network and then have to run back round to Segment 2 unless you branched those segments off a repeater.

There may be alternative solutions that I'm not aware of, so I suggest you engage with the Technical Support department of your preferred Hardware distributor to get the best solution to your specific requirements.
Hope that helps.
Thanks

Tom
--
Tom Chubb
[email protected]

 

Thanks Tom for replying,

Please see this topology.

http://i41.tinypic.com/2119r34.png

Please advise if I got it right.

Awaiting you comments

Thanks and Best Regards,
Jawwad

 

Dear Jawwad,

that topology is OK.

Armin Steinhoff

 

Dear Armin,

Thank you for your kind support. I am now going to implement this topology.

Bundle of thanks to:
you and Tom for such kind support =)

I really respect it a lot!

Many Thanks and Best Regards,
Jawwad

 

No problem.
Don't forget to ensure that termination resistors are active at each point where you have shown a black box on that topology. eg: at Master and end of Segment 1 and at both ends of each additional Segment (repeater end and far end)

Good luck!

Tom
--
Tom Chubb
[email protected]

 

If you have 2.4 km of twisted pair copper cable then you are going to have a problem with network speeds. The maximum cable length for a 1.5M baud rate is only 200M and I encourage you not to run maximum length segments. To use longer segments you either have to drop the baud rate substantially or replace the copper bus with fibre. Using fibre also isolates sections of the bus and will make your installation much more reliable.

If this is your first profibus installation, then I strongly suggest you ensure your installer follows installation rules correctly. You cannot allow them to take shortcuts by using the wrong cable types, leaving loops hanging in the cable trays, ignoring the shielding rules or not fitting and terminating plugs correctly. Using optical fibre segments helps make the bus much more reliable.

Rob
www[.]lymac.co.nz