Chapter 2: Installation and wiring
64
Vigilant VS1 and VS2 Technical Reference Manual
Class A wiring (Style 6)
+
–
+
–
Loop
device
Loop
device
Loop card
Data line
Loop SEC
Loop PRI
Class A wiring (Style 7)
Loop SEC
+
–
Loop PRI
+
–
Loop card
Loop
devices
Isolator
module
Isolator
module
UL/ULC listed enclosure
Data line
Loop devices
with isolator base
Loop card LEDs
There are three LEDs on the card that indicate loop communication
status. Primary is the primary communication circuit. Secondary is
the Class A return communication when wiring is Class A. Comm is
overall loop communication.
Loop card LEDs
Primary
Secondary
Comm
