Testing RS485 to RS232 adapter

Testing the RS485 to RS232 Adapter

You will need 2 RS-485 interfaces to test this so it is best to connect the adapter RS-485 side to I/O-485-3 of a 2DS2S card. Any Modbus card or interface will work, the 2DS2S is just a simple interface to use. Just connect “+” to “+”, “-“ to “-“, and “ground” to “ground”. Connect the RS-232 side of the adapter to your PC’s comm port and open TeraTerm to this comm port.

Login to the command line of the S550 w/ the 2DS2S card using any command line method and issue the bypass 3 command. Ensure that the baudrate of I/O3 and of the TeraTerm connection are the same and set I/O3 portmode to “Reserved” or “Data”(if reserved is not available). At this point, you should be able to type into the bypass connection on I/O3 and whatever you type should show up in the TeraTerm comm Port interface. Likewise, if you type into the TeraTerm CommPort interface, you should see the characters in your Bypass 3 interface. You will not get a “local echo” – the characters you type will end up in the “other” interface. If this goes smoothly, then your adapter is working properly. See below:

Date	Document Change
07 April 21	Added History Table
07 April 21	Updated formatting