| We are using the COMX driver with a
half-duplex RS485 connection (two wires, one for "+" and the second
for "-"). On this kind of connection we have to use a converter
(converts from the computer RS232 to RS485 two wires). We also use
the "-t" COMX switch which means transmit when RTS is high and
receive when RTS is low (when RTS = 0). When we set it to transmit
on RTS and receive on not RTS, it seems like the controller doesn't
receive the full message sent (the Rx led on the controller is
light but no Tx led indication for a reply). When we set the
converter to always transmit and receive (which is the case in
RS422, a full duplex - 4 wires connection), we see that the
controller receives the request (Rx indication) and immediately
replies (Tx indication on the controller), of course we do not get
this reply (we use RS485 connection with converter configured for
RS422, so we get only echo on everything we
transmit...). |
