VRF Protocol Gateway
12
7.2.1 Material Selection for Communication Iine
Communication
system
Type of
material
Length
L (m)
Cable
diameter
(mm²)
Material
Standard
Remarks
Communication
between
gateway and
BMS via
Modbus
Shielding
light/general
PVC jacket
twisted pair
L≤800 ≥2×0.75
IEC
60227-
5:2007
When the
communication
distance
exceeds 800m, a
PV isolation
relay should be
added.
7.2.2 Communication Connection Method
NOTICE!
All communication connection lines under Gateway must be in series
connection, star connection shall not be adopted.