Circutor CVM-C4 Series - RS-485 Communications; Connections

50
CVM-C4
Instruction Manual
7�- RS-485 COMMUNICATIONS
The CVM-C4 devices have an RS-485communications port, with communications protocol:
MODBUS RTU ®.
7.1.- CONNECTIONS
The RS-485 cable must be wired using twisted pair cable with mesh shield, leaving a maximum
distance between the CVM-C4 and the master device of 1200 metres .
A maximum of 32 CVM-C4 devices can be connected to this bus.
To establish the communications with the master device, we must use a smart RS-232 to RS-
485 network protocol converter.
BA
RS-485
S1 S2
S1 S2 S1 S2
I1 I2 I3
U1 U2 U3
UN
B
A
RS-485
S1 S2
S1 S2 S1 S2
I1 I2 I3
U1 U2 U3
UN
5849 50 21
4
5
6
7
8
9
11
12
13 14
47 48 59 70 71 72 15 16 17 18
5849 50 21
4
5
6
7
8
9
11
12
13 14
47 48 59 70 71 72 15 16 17 18
B(-)
A(+)
RS-232 / USB / Ethernet / Profibus ...
PC
RS-485
RS-485
RS-232
USB
Ethernet
Profibus
...
Figure 21: RS-485 connection diagram�
Note: Default values of the RS-485 communication: 19200 bps, No parity, 8 data bits and 1
stop bit.