Problem with Profibus

[ashkan]

hello mr Pedersen
we have same problem in our factory , we have one master and 4 slaves with 15 profibus node on every slave's node and 1500 meter perofibus cable . since 3 month ago , we have had flashing alarms in some nodes
this flashing is very short but that problem cause bus fault on some of nodes . for solving this problem we did under work:
1-cable test an fixed them
2- connector test and fix them
3- earth test and fixed them
4-we devided our nodes with cp . cp443-5
5-we check hardware and software
6- we chek repeaters and fix them
there is an intresting thing , systems are ok for ( for exampel 4,5 or etc) but sudenly start flashig .sometimes this flashing is very short sometimes is very long and stoped our productions line . also this problem crevasse to another system's .
for abatement of stop we use of jump for reset fault with software .
also this flashing is very short.
our cpu's : 415-2dp and level of rates 4-4.5 (tested with profibus tracer )
thank's if you can help me .

 

[KalleOlsen]

Hi! I'm not Mr.Pedersen, but while you are waiting...

1. Does your profitester have some node statistics? One of the nodes can be jamming the bus. Have had such experiences with MM4 proficards - caused by overheated cabinets.
2. You may make your system more robus if you change the standard DP settings to user defined settings with significantly longer watchdog timeout.
3. Most important: Are the infrastructure according to Profibus installation Guidelines ? ( http://www.profibus.com/downloads/ in the section "Installation Guide". If not; rewire or add fiberoptic links.

Kalle

 

[JesperMP]

I must be "mr pedersen".

Next time, I think it is better to start a new thread. Just because it has to be about Profibus, it may have nothing to do with the original thread. I also think that the original posters may dislike getting notifications that are irrelevant to them.

Anyway.
Next time the error is present, investigate the hardware diagnostics and/or the diagnostics buffer in STEP7.

If you really have a profibus analyser, then investigate if the shape of the signal between A-B, and A-ground and B-ground looks correct. If the shape is not correct, the Profibus system may just barely be able to function, but will fall over at the slightest disturbance.
Also, the Profibus analyser I have worked with had a nifty trigger function, so that the curve would be stored, but only when an error was detected. This is great for locating intermittent errors.

 

[ashkan]

I must be "mr pedersen".

Next time, I think it is better to start a new thread. Just because it has to be about Profibus, it may have nothing to do with the original thread. I also think that the original posters may dislike getting notifications that are irrelevant to them.

Anyway.
Next time the error is present, investigate the hardware diagnostics and/or the diagnostics buffer in STEP7.

If you really have a profibus analyser, then investigate if the shape of the signal between A-B, and A-ground and B-ground looks correct. If the shape is not correct, the Profibus system may just barely be able to function, but will fall over at the slightest disturbance.
Also, the Profibus analyser I have worked with had a nifty trigger function, so that the curve would be stored, but only when an error was detected. This is great for locating intermittent errors.

***********************************************************
Hi jesperMP
Thanks for your help . Can I know your profibus analyser's name . we have profitrace2.
thank you very much.
-----------
Ashkan

 

[JesperMP]

Yes, we also use the profitrace2.
http://www.procentec.com/profitrace2/index.php

 

[ashkan]

Hi! I'm not Mr.Pedersen, but while you are waiting...

1. Does your profitester have some node statistics? One of the nodes can be jamming the bus. Have had such experiences with MM4 proficards - caused by overheated cabinets.
2. You may make your system more robus if you change the standard DP settings to user defined settings with significantly longer watchdog timeout.
3. Most important: Are the infrastructure according to Profibus installation Guidelines ? ( http://www.profibus.com/downloads/ in the section "Installation Guide". If not; rewire or add fiberoptic links.

Kalle

***********************************************************
Hi Kalle
Thakns for your help . We checked many thing's , this flashing is alternate and trnsfer to another slave's suddenly, yesterday was in one slave system and today is in another systems . Sometimes all of things is ok but in specific time some nodes have flashing fault .That is very short Flash and we can't find main start point . Did you see equivalent error before?
_______________
Ashkan

 

[KalleOlsen]

Yes, yes, yes, I have seen such behavior - mostly due to improperly made infrastructure and earthing. Here will normally a fiber optic link be the best medicine. Did you check the guideline and also did you check if the profibus is laying close to power cables? Frequency converters, solenoids, motors and communication equipment can interfere with the bus and make dropoputs.

To try to plaster the problem; change your bus setting to 'user defined', and increase the retry limit to ...say 10. If you run the bus with speed over 187,5 kb/s, select a lower speed.

K

 

[JesperMP]

If you really have a profibus analyser, then investigate if the shape of the signal between A-B, and A-ground and B-ground looks correct. If the shape is not correct, the Profibus system may just barely be able to function, but will fall over at the slightest disturbance.

So what did you find out ?

 

[ashkan]

profitrace

So what did you find out ?

********************************************************
Hi jesperMP
That fault disappeare now and we have a special program for production . When i checked your solution , I did't see any problem in level of network voltage. the bargraph is ok.
Withal , We get this tester lately . We are waiting for flashing fault than we check and see Difference's.
Thanks for your help.
_______
Ashkan