MMI/PLC Networking

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Thread Starter

McConnell, David P

I am looking for practical (and cost effective) suggestions for establishing a maximally robust network inter-connection between an Allen Bradley PLC-5 ControlNet PLC and Wonderware Intouch. We currently utilize an Ethernet to interface several NT-4 workstations running the ABTCP I/O Server and Intouch. The Ethernet network consists of two hubs interconnected by fiber. Workstations are connected to the hubs via 10BaseT. The network is isolated in that nothing other than the PLC, a printer and the workstations are connected. The PLC5-80C utilizes an Ethernet sidecar (1785-ENET) for network interface and is remote from the workstations. The ControlNet network does have presence at the workstation location. Recently, at the most inconvenient moment imaginable, we experienced a hardware failure in one of the hubs. The PLC operated normally, sensed the loss of connectivity and performed an orderly shutdown of the process as programmed. However, I do not want this to happen again, ever! Any suggestions? David McConnell Boeing Company Rocketdyne Propulsion and Power Stennis Space Center, MS.
 
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Jay Benedict

If you go to RSLinx "full blown" you should also be able to access the plc through the "controlnet" using DDE to Wonderware provide you have a ktc15 card in your workstaion as well as your ethernet NIC. This could be the redundant connection you are looking for. Have to admit that I am not that familiar with the 80-C as with controlnet and control logix processors. Know you can do it with a Logix processor. The only other issue would be the Wonderware commands monitoring your ethernet and controlnet i/o servers. These are really not that difficult either, there are examples of heartbeats and such in the wonderware knowledgebase. Good Luck J
 
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Timothy P. Heckman

If you want some redundancy in your Ethernet network check out either Phoenix Digital or Hirschmann Fiber Optic Ethernet products. Both have a dual counter-rotating, self-healing ring approach... I have used the Phoenix Digital successfully, and will be putting in a Hirschmann setup soon. Timothy P. Heckman Sr. Application Engineer Edison Automation, Inc. 615.256.2522 x113 www.edisonautomation.com <http://www.edisonautomation.com>
 
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Curt Wuollet

Buy hubs with internal power and use a UPS. Most failures I've seen relate to the wall warts and dubious power filtering. An even better idea is to keep the DC hubs and use a real power supply to feed them. Find a cool place for the hubs, most have no ventilation openings and are office rated. Even the cheap ones are amazingly reliable if you control the environment a little. We could get into lightning protection but I don't know if that's relevent. Above all, you should analyze the failure so you know how to prevent it. Regards cww
 
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Walters Curt L Contr AEDC/SVT

Although you would have to evaluate the practicality and cost-effectiveness, if you switched to a GE-based system you would get redundancy. The GE PLCs can use two Ethernet cards and the GE HMI software also supports redundant Ethernet. It also supports redundant HMI servers. I am currently using such a setup and it works great. I have also used Westinghouse WDPF DCS which has redundant networks. But this is $$$. Curt Walters
 
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Greg McClemont

> Hello Favid - noticed in your e-mail that you are using Intouch with the ABTCP I/O server. We are now attempting to establish a similar network with Intouch version 7.0 and ethernet PLC-5's. Having a great difficulty getting 7.0 to communicate properly - the comms have to be initiated manually through the menu bar (Initialize IO) and occassionally stop for no reason. We are stuck with 7.0 due to existing systems, licensing etc. Did you have any difficulties of this type - any suggestions?
Regards,
Greg McClemont
[email protected]s.com
 
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