GR-750x series
Control panel for addressable emergency
luminaires
Document number: 923750400_09_007
Date: 3/5/2022
Page: 22 of 71
[22]
3.4 Panel network wiring
Table 8
– Panel network specifications
Panel network specifications
Maximum number of panels
24
Maximum cable length*
1
800 meters *
1
Recommended cable type
2-core shielded twisted pair cable
with stranded wires
Communication protocol
RS-485
Network Isolation
YES
Fault tolerance
YES (single wiring fault)
Electrical protection
YES
*
1
Maximum length of a single cable connecting two panels.
To connect the panels and form a network either of the
NET-L
or
NET-R
terminals, located on the power
management board, can be used. The
NET-L
terminal must be connected to the
NET-R
of the other panel
and the
NET-R
terminal to the
NET-L
of the other panel. Connecting
NET-L
terminal of one panel with the
NET-L
of another panel, will not work. The same is true for the
NET-R
terminal.
IMPORTANT
•
If two panels need more than 800m cable to be connected, a RS-485 repeater must be
used.
•
The shield of the cable must be connected to the earth bar of one of the panels it is
connecting, not on both sides.
To be operational, only one side of the panel network is required to be connected (
NET-L
or
NET-R
), not both.
That is the
open ring
panel network topology (Figure 11). If both sides are used (both
NET-L
and
NET-R
)
then the resulting network is a
closed ring
topology (Figure 12). The advantage of the closed ring I that a
single fault along the communication lines is not enough to disrupt the communication between the panels on
the network. That is not true for an open ring topology.
The panel network ring is monitored for open/closed status and a fault can be produced when it is open
(configurable from the panel network parameters menu). Using a
closed ring
is not mandatory but
highly
recommended
for the reliability of the panel network.
Figure 11