485 communication

[ashish]

we have a requirement to compare the codes from 2 different bar code scanners and generate digital high or low outputs according to code comparison.
both the bar code scanners are of RS 232 output type.
we tried to use T100MD 88 plc for this application.
one bar code scanner connected to rs232 port (port1) and another to rs485 port(port3) through 232 to 485 converter.
but we are not getting able to get the bar code data on port3.
for trials, we connect the bar code scaner to port3 ie rs485 port through 232 to 485 converter (2 wire auto type) and we tried to monitor the input contents by connecting trilogy software through port1.
but we did not get the data in register.
is it possible to use rs485 port to read the data from external device such as bar code scanner ?
data is in ascii format and boud rate, protocol settings were made as per required for system.

this is very urgent since we are on site for this work.

[support]

You did not mention if your RS232 to RS485 converter is the Auto485 converter that we sell? We won't know what settings are required if it is other brands.

If it is Auto485 then you should be able to read the barcode data coming in from comm3 using the INPUT$(3) command if the incoming characters are terminated by CR (ASCII code 13). If the incoming data is binary then you can read incoming binary data into DM area using the INCOMM(3) statement.

Are you able to use the TLServer to talk to the PLC using the RS232 to RS485 converter. You can try the "IR*" test. If it is successful, then try using TRiLOGI to go online monitoring via the RS485 port (through the Auto485 converter). If you can perform online monitoring via COMM3 then your Auto485 is working fine and it is only a matter of getting the software written correctly to read data from the barcode reader via RS485.