We have used Wonderware MBENET for communication with MODICON Quantum PLC. The tag count is more than 10000 and the no of topics names is to be more than 30. We are facing problem with MBENET and facing the problem of communication failure/Dr. Watson on Windows NT due to IO server failed.

It has been suggested that Topserver OPC from softwaretool box is a better option for such a big requirement of ethernet communication. I need user/expert views on this matter.

 

Dear Vashist

Here are some of the options witg which the problem may be solved.

1. Did you try using some other NIC(ethernet) card instead of the one you are using.

2. Is the driver software of the NIC ethernet card is the right driver for Windows NT?(sometimes drivers are incompatible in WnNT

3. Distribute the topics and I/Os of the Quantum and try to use two or three different cards in the same PC with different IP addresses.The MBENET driver indeed support multiple cards in the same PC.

Hope this helps.

Thanks and Regards
Jayaharan C J
[email protected]

 

Dr Watson should NOT come up with the latest MBENET rev (7.6.0.0). Try the newer version of the MBENET before attempting TOP.

You can try the TOP out for free before trying too.

 

You might want to check with Kepware I beleive that the Top Server product is their kepserver product with a different name. Kepware can make changes to the driver if you need it. They did it for us to allow a project with over 256 PLCs with each PLC on its own communications task. Made the app run great. We had around 15000 tags.

 

As other people have said, try the latest MBENET version.

However, be aware that ALL Ethernet devices will have a socket limit. Most PLC will be in the 32 to 64 or 100 range. You mention 10000 tags - even at 125 registers per poll you could have 80 or more "transactions" active.

I do NOT know if MBENET will use more than one socket to speed this up - I know they use more than 1 socket for Modbus/TCP bridge access. It is possible your driver is opening too many sockets for the PLC and running into socket thrashing problems with some of those sockets failing. Most client applications get very upset if some sockets fail and others don't - they like consistant behavior; all or nothing.

This is just a guess, but if this is your problem even a new OPC server may not help. See if you can identify the problem better before you buy new software. Also consider adding PLC logic to "pack" commonly polled data neatly into unused register space so fewer polls can get more data. This may help the socket issue (if it exists).

- LynnL, www.digi.com