RS 485 Connections

Dear All,

I would like to connect a Touch panel via a Radio modem to the PLC for Remote montoring. Its a 2 wire RS 485 connections on both devices. But i found that in touch panel Data A is (-) and Data B is (+). But in other device (ie) PLC, Data A is (+) and Data B is (-). If i connect through the cable it works fine but if i connect through Radio modem it does not work. i tried reversing the polority but no response. So please advise. Waiting for your reply.

With regards.

Libbysen

You have to establish the correct + & (-) on the radio, as well as on the devices:
Data B+ > radio+ wireless Radio+ > Data A+
Data A- > radio - Wireless. Radio- >. Data B-