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Re: Rs485 problems



Robert Hibberdine wrote:

> cable with the Axis 82 about 70 metres from one end. Both ends of the
> cable are terminated with 120 ohms. In this situation the application
> can only (sometimes) see the nearer logger when using ttyS3.

Try connecting the external RS485 converter to the bus to see if the
problem is with transmission or reception. Did you have the termination
resistors connected when you tested with a short cable? Have you checked
the grounding, i.e. that there's no large common mode voltage on the bus?
What kind of cabling and transmission rate you are using?

Good luck,

Jarkko