10/5/2020 2:52 PM | |
Joined: 9/27/2006 Last visit: 6/30/2024 Posts: 12264 Rating:
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Hello Mahdi; Murof is right, an HMI and a Profibus DP slave are very limited in their possible data exchanges. Let me try to explain why. First, this document from Felser.ch ("Profibus University") gives you definitions for Masters Class 1 and Masters Class 2 on Profibus: https://www.felser.ch/profibus-manual/ms1_ms2_azyklischer_datenaustausch.html A PLC is a Master Class 1 on Proifbus: it holds a very defined list of configured slaves (with all their parameters) in its memory, and polls each of them cyclically when it is allowed to (when it holds the Profibis network token. Other data exchanges are also allowed (DPV1 standard, for example). An HMI panel acts as a Profibus Master Class 2, a supervisory station on Profibus. It is allowed to interrogate existing Profibus Masters Class 1 on the network to retrieve data that it needs to fill its tag list and screens, as required. It cannot poll Profibus slaves directly as it does not hols a configuration for these slaves, it retrieves data from the Master that it has polled from each slave it is configured with. So introducing a small PLC as a Profibus Master Class 1 in your network will solve your issues. Hope this helps, Daniel Chartier |
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