Auxbus Grounding Principles - Danfoss iC7 Series Design Manual

Design Guide | iC7 Series Air-cooled System Modules
RISK OF ELECTRICAL INTERFERENCE
AuxBus consists of point-to-point connection, but the signals are connected in series. Cables that are longer than 10 m (33 ft) can
create interference and communication problems.
Do not exceed 10 m (33 ft) of total AuxBus cabling.
l
Keep AuxBus cables as short as possible and separate them from high-power cables.
l
Table 13: Cable Requirements for Other than Danfoss-provided Cables
Item
Cable type
Impedance
Maximum length
Cable (example): LAPP KABEL, UNITRONIC® BUS LD FB P, 2170215.
Cable (example, UL): LAPP KABEL, UNITRONIC® BUS LD FB P A, 2170815.
Connector: Phoenix Contact, MC 1,5/ 5-ST-3,5 BK, 1769919 (LCL Filter: 2721-105/026-000).
Cabling recommendation for drives with a loose option AuxBus
Cabling recommendation for drives with integration unit filters

AuxBus Grounding Principles

6.14.3
To ensure robust communication, good grounding strategy is needed. Below is a recommended grounding strategy illustrated using
integration units. Same strategy can be applied for loose option filters.
A
X25
+24 V
1
GND
2
CAN_H
3
CAN_L
4
+24 V
5
Figure 34: AuxBus Circuit Diagram
A
The AuxBus interface in the power unit
C
AuxBus board 2
Danfoss Drives Oy © 2024.03
NOTICE
B
X86 X85
+24 V +24 V
1 1
GND GND
2 2
CAN_H CAN_H
3 3
CAN_L CAN_L
4 4
+24 V Term. Disable
5 5
Value
6-wire, shielded and twisted pair (STP)
120 Ω
10 m (33 ft)
C
X86 X85
+24 V +24 V
1 1
GND GND
2 2
CAN_H CAN_H
3 3
CAN_L CAN_L
4 4
+24 V Term. Disable
5 5
B
AuxBus board 1
D
AuxBus board 3
AJ389643111587en-000101 / 172F6361A |
D
X86 X85
+24 V +24 V
1 1
GND GND
2 2
CAN_H CAN_H
3 3
CAN_L CAN_L
4 4
+24 V Term. Disable
5 5
47