Galvanic Isolation Barriers - Honeywell SmartVFD HVAC MR4 User Manual

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ONTROL UNIT
6.4

Galvanic isolation barriers

The control connections are isolated from the mains potential and the GND terminals are per-
manently connected to ground. See Figure 58.
The digital inputs are galvanically isolated from the I/O ground. The relay outputs are addition-
ally double-isolated from each other at 300VAC (EN-50178).
10Vref
GND
+24V
GND
AI1+
AI1-
AI2+
AI2 -
DI1...
DI6
CM
DI1...
DI6
CM
AO1+
AO1 -
+24Vin
RS485
RO1/1
RO1/2
RO1/3
RO2/1
RO2/2
RO2/3
TI1+
TI1-
Control I/O
ground
Control
keypad
Digital
input
group
Control
Analogue
board
output
Figure 58. Galvanic isolation barriers
L1 L2 L3
Communication
Power
board
U V W
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