46
RECmax-CVM
Instruction Manual
7.- RS-485 COMMUNICATIONS
RECmax-CVM
devices feature one RS-485 communications port� The device has uses the
MODBUS
RTU
communications protocol as the standard protocol�
7�1�- CONNECTIONS
The RS-485 cable must be wired with twisted pair cable with mesh shield (minimum 3 wires), with a
maximum distance between the
RECmax-CVM
and the master device of
1200
metres�
Up to 32
RECmax-CVM
devices can be connected to this bus�
Use an intelligent RS-232 to RS-485 network protocol converter to establish the communications with
the master device�
B(-)
(4)
A+
(5)
S
(3)
B(-)
A(+)
S
RS-232 / USB / Ethernet / Profibus ...
PC
RS-485
RS-485
RS-232
USB
Ethernet
Profibus
...
Figure 35: RS-485 Connection diagram�