Hi,

I use MSG commands from one PLC with a ENBT Module (Rev. 3.xx) to another with EWEB Module (Rev. 4.xx).
Bouth PLC`s are on Rev. 15.xx
Connection works, but sometimes (once in 10 Minutes) the Tag-update take up to 10 Seconds, wich is way to slow. The normal rate is about 100 ms. The hardware is fine so far.
I had the same Problem with two ENBT Cards (Rev. 4.1) and Processor Rev. 15.xx or lower, they was`t compatible, but EWEB Card`s with Rev. over 4 should be no Problem on Processors Rev. 15.xx or lower???

Somebody had the same problem or any ideas??

The problem you describe is systemic to Ethernet. Unlike DeviceNet, COntrolNet and Remote IO there is no determinism to ethernet. You will have to examine several things to find the root cause of your long message time.

Each PLC has a message buffer and if either one is overfilled you would ahve to wait to complete communications.

Each PLC has a connection limit and so does each ENET or EWEB module. Approaching limits on conenction count can cause delays in emssage propagation.

You are working with Ethernet Routers and Possible bridges which must pass otehr trafic as well as yours. Any competing traffic could cause this delay.

Others will list more, but this post should scratch the surface.

Are you using a data table write/read to send the MSG?

Make sure that the receiving end isn't buffering. On the EWEB, you can check that by opening its webpage, going into Advanced Diagnostics, and checking the message buffers.

Are you running any continous tasks in the receiving controller? If so, try using periodic tasks instead, and make sure that the task which is doing the receiving is firing at least twice as fast as the sending task. This caught me before when I ran both at the same firing interval, the buffer filled up and my receives got more and more delayed.

If you absolutely have to run a continous task, try increasing the communications Time Slice in the controller properties, as your controller may not have enough resources to handle the communications load.

If all else fails, you can be cool like me and use two EWEBs, with open sockets, for all your communications ;)

Hi,

thank U all for the quick response
I learnd some new stuff by that.
Finally the main problem what i had was the 600 ft long ethernet connection wires (only Cat5) to the hub. The installation company didn`t follow the orig. drawings. I hat to make a direct connection, have now max 120 ms interrupt...
Next installation like that i guess we need fiberglass.

Thanks again!