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Need advise - Termination Resistors Values at Field Link Device - 781

Hello Champ,

We are working on Wireless project ( Emerson 1410D and 781 connected using powered barrier with Belden Cable 3084a ) .

As per the quick start guide 00825-0200-4410, Rev EA – Emerson (Wireless 1410 A/B and 1410D Gateway with 781 Field Link), recommended termination resistor is 250 Ohm across 1410D, GM Barrier and 781 field link for the best performance.

However, for RS485 communication typical termination resistor is 120 Ohm (Emerson recommended belden cable 3084a has 120 Ohm impedance)

Please advise, if 250 Ohm is correct or not ? (Customer is asking for the reason behind using 250 Ohm resistance for RS485 communication)

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