Computer Interfacing
Discussions about interfacing and electronics

RS485 Stabilty Issue

Unstable communications


       Computer Interfacing Forum Index -> RS422 and RS485
Author Message
New User

Joined: 03 Jul 2011
Posts: 1

Jul 03, 2011 4:17 am

I am having a problem with an RS485 Modbus, interfacing from a controller to 5 power meters, baud rate is 9600.

The cable is in close proximity to a "Variable Speed Drive", when the drive is not in operation the RS485 communications is stable and the data is valid.

However once the VSD is ramped up to around 45Hz the interface becomes unstable and the data is no longer giving valid information.

We have tried earthing the scrren at one end and using EOL resistors but no joy.

Any recomendations here would be appreciated.

Aug 19, 2011 3:30 pm

Put RS485 cable to steel conduit.

       Computer Interfacing Forum Index -> RS422 and RS485
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