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EMI Effect on Communication Using Modbus Protocol
Need a method (or idea) on how to analyze the effect of EMI on data error

Hi..

I have two pneumatic controllers working with Modbus protocol. When tested it in real time, i am getting data error at the slave side. It is assumed to be because of EMI. Anybody knows any method (or idea) to analyze the effect of EMI on this data error?

Hello,

> When tested it in real time, i am getting data error at the slave side.

Some helpful advice, when asking for help with an error ALWAYS provide the error code/flashing light/print out/etc.

I can think of several "errors" for a MODBUS slave that have nothing to do with EMI.


My2c.

Good luck,
Mark
http://www.peakhmi.com/

By Bob Peterson on 13 December, 2016 - 12:31 pm

What led you to assume that EMI is your problem? How do you know you're even getting a data error on the slave end?

What physical layer are you using? If it is RS485 2 wire then it is more then likely: (1) Lack of termination resistors, or (2) lack of fail safe biasing, or (3) key up and key down timing issues, or (4) not having a 3rd wire common reference.