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Can I use the RS485 port on a bCX Comm 2 for a Plain English driver?


How to select between the RS232 and RS485 port on a bCX1 controller when sending / receiving ASCII data.


Serial port Plain English Driver

RAW Mode

Bcx1 9640, 4040


Unable to select RS485, the controller only transmits/ receives through RS232.


There is no switch exposed to Plain English that allows you to use the RS485 port on Comm2 of a bCX.

 A Netcontroller II would be able to do it as on Comm1 & 2, it has both RS232 & RS485 full circuits that work in parallel. So when you print from Plain English, the data goes out of both ports. You just need to control the RTS line of the port to switch between transmitting or receiving on the RS485 as it is half duplex.

The way the bCX Comm2 is wired internally it defaults to RS232 but there is no exposed parameter to switch to RS485. In the Modbus RTU X Driver there is the special parameter (Function 99) that has to be set to switch between the ports, but this switch is at a level that only an X Driver can access.

The options are: Use a Netcontroller II , or use a RS232/ RS485 converter (ensure it is not line powered), with the PE program sending / receiving on the RS232 port of the bCX. Possibly move to Comm1 of the bCX freeing up Comm2 for use with Infinet or BACnet controllers (assuming the node count is not 0).

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‎2018-09-06 09:06 AM
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