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Lossing Data Intermitantly over the PA/DP Coupler.
Created by: Raymondk at: 11/23/2010 8:42 AM (2 Replies)
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| 11/26/2010 6:54 AM | |
Joined: 10/7/2005 Last visit: 3/18/2025 Posts: 3042 Rating:
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Hello Raymondk havingintermittent Profibus (DP or PA) communciation problems is certainly not a"known problem" that relates to a specific part of the installation. It is the nature of any digital fieldbusthough that signal corruption (for whatever reasons) will lead to sporadic or longer term loss of communciation. The vast majority of fieldbus related communciation problems are caused bypoor installation (e.g. shield discontinuity, cable run in parallel with high voltage or drives cable,incorrect termination, exceeding permissble cable lenght etc.). While Step 7 will give diagnostic informationabout the lost DP or PA Slave, it simply can not tell the root cause of the dropout nor evalute thephysical signal level(or signal quality). To work out what is going on and how good or bad your bus is, you'd ideally get hold of adedicated troublehooting tool and use it to evaluate the bus (e.g. Procentec's ProfiTrace 2 which is my personal favourite, but I am also a bit biased in that regard). From what you describe Iwould assume your problem is related to the PA side, in which case THIS and THIS PA troubleshooting related docs from Siemens may interest you. You'll also find some very usefulfree of charge Profibus Installationand commissioning guidelines at http://www.profibus.com/downloads/ Last but not least, since PA instruments are commonly installed outdoors, water ingress in plugs and splices and/or distribution boxes joints isan additional potential "nice" problem to have (again, poor installation related, but worhthile checking the connections). No silver bullet I'm afraid but hope it helps anyhow |
Last edited by: fritz at: 11/26/2010 6:59 AMCheers |
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