RS485 communications between Emerson AMS and HART multiplexer

Hi,

I am trying to connect a PC running Emerson AMS to HART multiplexers with a MOXA 5150 ethernet to RS485 device server.

The system works OK when I use the PC serial port and a Westermo MD45 converter, and when I use a MOXA NPort 5410 (ethernet to RS232) and the Westermo, but no luck when I connect the 5150 directly :(

I have two different HART MUXes, a P&F ELCON 2700 and a MTL 4841, at the moment sitting in my office connected by short lengths of wire. They are terminated at each end with 110 ohm resistors. I have followed the setup instructions from Emerson. Any ideas on how to proceed would be welcome!

Geir
 
>I am trying to connect a PC running Emerson AMS to HART multiplexers with a
>MOXA 5150 ethernet to RS485 device server.

>The system works OK when I use the PC serial port and a Westermo MD45
>converter, and when I use a MOXA NPort 5410 (ethernet to RS232) and the
>Westermo, but no luck when I connect the 5150 directly :(

>I have two different HART MUXes, a P&F ELCON 2700 and a MTL 4841, at the moment
>sitting in my office connected by short lengths of wire. They are terminated at
>each end with 110 ohm resistors. I have followed the setup instructions from Emerson.

The problem seems to be lack of 1k pull-up resistor for the older type of MOXA, everything is OK when I use a newer version. Can anything be done to the old type device server?

Geir
 
Geir,

did you end up getting the AMS to talk to the P&F multiplexer through the Moxa 5150? If so, what did you do? I am having similar problems too.
 
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