Circutor CEM-C31-485-DS, Instruction Manual

Page: 41 / 58

7�- COMMUNICATIONS
7.1.- INFRARED COMMUNICATIONS PORT (Model
CEM-C31-T1
)
The CEM-C31-T1 model, in all versions, the has a serial optical communications port, in com-
pliance with the UNE EN 62056-21:2003 Standard.
7.2.- RS-485 COMMUNICATIONS PORT (Models CEM-C31-485-xx )
The CEM-C31-485-T1 and CEM-C31-485-DS models has an RS-485 communication port, with
MODBUS RTU ® protocol.
7�2�1�- CONNECTION
The RS-485 cable must be made up of a twisted pair cable with a braided shield with a
maximum distance of 1,200 metres between the CEM-C31-485-xx and the master device.
A maximum of 32 devices can be connected to this bus.
Use an intelligent RS-232 to RS-485 network protocol converter to establish communications
with the master device.
PC
B(-) A(+)
RS-485
A(+) B(-)
RS-232 / USB / Ethernet / Profibus ...
RS-485
RS-485
RS-232
USB
Ethernet
Profibus
...
Figure 19: CEM-C31-485-T1 and CEM-C31-485-DS connection diagram�
41
Instruction Manual
CEM-C31