Technical Documentation
BLR-CM Modbus
Rev. 05
2018-09
6
2.1.1
Connection
There are two Modbus interfaces:
a) 9-pin D-SUB
PIN1
+5V (For data line bias only. It is not allowed to supply external circuits by this pin!)
PIN2
Common ground (GND) for all bus participants.
PIN5
D (B) - Data signal B
PIN9
D (A) - Data signal A
b) 3-pin Connector
The power factor controller CM uses a 3-pin connector, which is
shown on the right side.
In order to establish a Modbus connection, the data lines + and - and
the common ground (middle pin) must be connected.
Attention: Various vendors uses the assignment A and B. Equating this designation (A = +) and (B = -) does not always
apply. This must be checked for each device.
5 4 3 2 1
9 8 7 6
