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Eradicated

2 PLC's + 16 HMI's - Ethernet traffic...

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I will briefly describe my control system. I've got the following devices hooked up into a network: 1 x CP1L-EM30DR-D 1 x CJ2-CPU32 16 x HMI (Pro-Face HMI's with Ethernet port). Don't as me why somebody decided to install 16 HMI's into such system, that's not my idea... The devices will communicate in the following manner: CJ2M will query CP1L for data using SEND/RECV commands. Typically about 20-30 words, with temporary increases up to ~500 word queries. Whereas the 16 HMI's will communicate with CJ2M (continuous communication), with approximated traffic of ~30 words per panel (with temporary increases and decreases in queried words count). Now I am worried if the traffic won't be too much for CP1L / CJ2M to handle? Won't CP1L overflow with data when this happy party starts to talk with each other? Did anyone had to deal with such amount of HMI's in the system or similar devices? In general response times are not the most important (200 ms between PLC's is fine). I wonder whether such configuration will handle such traffic. Should I maybe buyj CJ1W-ETN21 card and separate CP1L-CJ2M communication (with separate tunnel via managed switch) and CJ2M-HMI's communication (they would be connected to CJ1W-ETN21 card in such configuration). I would like to cut down the costs, so I would rather not buy the CJ1W card. I would be very grateful for any advice! Here's the image which visualizes the physical connection map for the system: https://dl.dropboxusercontent.com/u/23860146/mrPLC/pConn.JPG Edited by Eradicated

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I would definitely add the ETN21 card to handle those HMI's as a separate network. That should allow the two PLC's to communicate without concerns about the traffic level. If the HMI's slow down, that is something the customer will have to live with. It was their idea to run this configuration. It might work the way they have it configured, but if it doesn't you will of course get the blame for it.

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