Harrington Signal HS-3200 - Install Manual - Manual (Page 12)

HS-3100/3200 Installation Manual
6
Testing Circuit Supervision
Use the following procedures in the table below to confirm that SLCs and NACs are supervising for
opens, shorts, and grounds. The right column in this table shows the LEDs that illuminate when an
open, short, or ground occurs on a specific circuit. AUX is supervised for shorts and earths only.
Open (NACs) -- Remove the end-of-line
and make circuit impedance infinite.
Open (SLCs) -- Break the line anywhere in
the loop. NAC illuminates the Trouble LED and the
NAC Trouble LED flashes
SLC illuminates the Trouble LED
Short -- Apply a zero ohm jumper across
the circuit. SLC illuminates the Trouble LED
NAC illuminates the Trouble LED and the
NAC Trouble LED flashes
AUX illuminates the Trouble LED
Earth Ground (NACs) -- Place a 10K
Ω or
smaller value resistor from the supervised
wiring to Earth Ground.
Earth Ground (SLCs) -- Place a 100
Ω or
smaller value resistor from the supervised
wiring to Earth Ground.
If an Earth Ground occurs on any circuit the
Fault and Trouble LEDs both illuminate