BM85 to BM85 via Radio Modems


Thread Starter


I've read the hints regarding using BM85 Bridge MUX units with radio modems (using ASCII etc) but i am yet to find an example of someone communicating as follows:

Quantum PLC A via MB+ processor port (MB+ address 1) --> BM85 MUX A via Port 2 (MB+ address 5) --> Radio Modem A --> Radio Modem B --> BM85 MUX B via Port 1 (MB+ address 5) --> Quantum PLC B via MB+ processor port (MB+ address 1)

I have the Control Routing words set up as follows when reading from PLC A to PLC B:

Routing Register 1 - MUX A MB+ address = 5
Routing Register 2 - MUX A Port = 2
Routing Register 3 - MUX B Port = 1
Routing Register 4 - MUX B MB+ address = 5
Routing Register 5 - PLC B MB+ address = 1

giving 5,2,1,5,1

I would like to confirm the configuration of the Routing Registers in the above example i.e I am not sure if the MUX B port needs to be included (Routing Register 3).

Any other hints/tricks when configuring this setup?
Hi Brad,

Don't include BM85 Mux B in the routing path. Effectively, you are talking PLC to BM85 to PLC.

Using 2 BM85 MUX units is an expensive way to go. Here are a couple of alternatives for you.
1. Use modbus directly instead of MB+. Connect the radio modems to the modbus serial ports on the Quantum PLCs. That way you don't need the BM85 MUX units.
2. Use MB+ radio modems. There is only MB+ radio modem one on the market as far as I know - Modpac Plus RF Modem made by Curry Controls.

Jamie Downs
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