Thread Starter



i am new in Beckhoff products (PLC) and MODBUS so please help ...

i have Beckhoff PLC BX8000-0000 with KL6041-RS422(485), 24Byte serial interface.

This serial interface is connected with Modbus device NOVUS N2000 (slave address=2, MODBUS RTU 485) by terminals:<pre>
KL6041: N2000:

TxD+ to D1(between D1 and D0 =
termination resistor)
TxD- to D0

GND to GND</pre>
You can find link: with my source code (TwinCat). i want to read first 10 registers from slave device to Beckhoff PLC.

I don't have software KS2000 for interface configuration, so i configured serial interface in source code by function block KL6configuration and i also used
function block ModbusRtuMaster_KL6x22B.ReadRegs for reading registers from slave.

But in function block KL6configuration i allways get error : COMERROR_TIMEOUT .

In function block ModbusRtuMaster_KL6x22B.ReadRegs i have no error !!

Please help: how to configure KL6041 serial interface to works like RS485 and also works without errors

Thank You very much,

Best regards!!

P.S. please note:
Modbus device NOVUS N2000 ... all parameters are O.K. and works fine with other device on the same parameters!!