Technical Documentation
BLR-CM Modbus
Rev. 05
2018-09
21
4
Trouble shooting
If the bus connection is not working correctly, please check the following points:
1.
If no communication can be set up, the error must be searched between the BLR-CM and the PC:
Approaching:
-
Check the adjustment of baud rate, parity and slave number at the BLR-CM. If necessary, change
the configuration.
-
Are the bus lines A and B correct connected? Maybe they are interchanged.
-
Check the adjustments of the converter RS485/RS232, possibly consult the data sheet of the
converter
-
Perhaps the PC port is already used by another application. Avoid multiple port reservations.
-
Check the termination and bias resistors.
2.
Has the bus cable any damages? Are all plugs connected correctly? If necessary, they must be replace.
3.
Is the pin assignment of the RS485 connection correct? If necessary, it must be changed.
4.
The shielding of the bus line must not be used as bus ground. Nevertheless, the shielding should be connected
to ground.
5.
Is the communication possible, but there are problems with the software:
-
Check the adjustment of baud rate, parity and slave number in the software. If necessary, change
the configuration.
-
Check used data format
