Datasheet

Fieldbus loop
Each GD controller can handle up to 96 sensors
and handle any mix of individual Gas detection
units of the types Basic, Premium and Heavy
Duty.
The max. recommended loop wire length is 900
meter (2953 ft) per segment.
With additional segments (and additional
controller expansion modules) the max
recommended loop wire length is 7200 meter
(23622 ft).
The controller and the last GDU in each segment
must be provided with a resistor of 560 Ohm.
A Umin of 16 V DC must be secured at any spot in
the loop.
Below gure shows how to make proper
connections between the controller and each
GDU.
GDU Addr. 05 GDU Addr. 04
560 R
Controller Unit
0 V DC
24 V DC
BUS_B
BUS_A
0 V DC
24 V DC
4
3
2
1
4
3
2
1
4
3
2
1
4
3
2
1
4
3
2
1
U
min
= 16 V DC
GDU Addr. 01 GDU Addr. 02 GDU Addr. 03
Danfoss
148H139_01-2018
= Terminating resistor 560 OhmR
R
R
= GDU (Basic, Premium and/or Heavy Duty)
R
R
RIGHT
WRONG
Controller
unit
Controller
unit
Wire length max. 900 meter (2953 ft) per segment.
More segments with additional expansion modules max. 7200 meter (23622 ft).
Additional power limitations must be calculated.
Danfoss
148H123_03-2018
GDU Addr. 05 GDU Addr. 04
GDU Addr. 01 GDU Addr. 02 GDU Addr. 03
Controller
unit
Wire length max. 900 meter (2953 ft) per segment.
More segments with additional expansion modules max. 7200 meter (23622 ft).
Additional power limitations must be calculated.
Controller
unit
Controller
unit
= Terminating resistor 560 Ohm
= GDU (Basic, Premium and/or Heavy Duty)
RIGHT
WRONG
Data sheet | Danfoss gas detection units, types GD Basic and Basic+
6 | AI272545693488en-000303
© Danfoss | DCS (ms) | 2019.10