RS485 cable requirements
2
RS485 cable requirements
The communication is running on RS485 line and must be connected by cables specially
designed for this. These cables should conform demands by EIA-485 specification. (E.g.
see BELDEN 3016A)
It requires shielded twisted 2-pair cable or 1.5-pair cable. Recommended thickness
of cable lines is 0,2 - 0,32 mm
2
(24 - 22 AWG,
0.5 - 0.65 mm)
One twisted pair is used for connection of A and B. Remaining line(s) are used for
GND connection.
Shielding of the cable must be attached on the chassis of
one
of the devices. Best
practice is to attach it on the outmost indoor unit chassis.
6 Modbus Gateway