CIRCUTOR CVM-B Series - Manual (Page 176)

6�- INTegRATeD COMMUNICATIONS
The CVM-B units have one RS-485 communications port.
The unit has as standard two communications protocols: MODBUS RTU ® and BACnet.
The protocol and configuration parameters are selected on the setup menu. ( “5.6.18.- In-
tegrated communications.” ).
The unit is factory configured with the MODBUS protocol.
6.1.- CONNECTIONS
The RS-485 cable should be wired with a twisted pair cable with mesh shield (minimum 3
wires), with a maximum distance between the CVM-B and the master unit of 1200 metres.
A maximum of 32 CVM-B units can be connected to this bus.
Use an intelligent converter to establish communications with the master unit.
B ( - )
RS-232 / USB / Ethernet / Profibus ...
PC
B ( - )
A ( + )
RS-485
S
A(+) B(-) S A(+) B(-) S
RS-485
RS-232
USB
Ethernet
Profibus
...
figure 141: RS-485 Connection diagram�
176
CVM-B100 - CVM-B150
Instruction Manual