![background image](http://html.mh-extra.com/html/northern/n-1000-iii/n-1000-iii_installation-and-programming-manual_1708226041.webp)
5–4
5–4
5–4
5–4
5–4
N-1000-III/IV
N-1000-III/IV
N-1000-III/IV
N-1000-III/IV
N-1000-III/IV
Section 5: Operation
Section 5: Operation
Section 5: Operation
Section 5: Operation
Section 5: Operation
5-2: Alarm Input Points
All N-1000 alarm input points default to normally-closed, non-supervised circuits
used to monitor changes of state. N-1000-III/IV inputs can also be configured for
normally-open circuits and 3-state supervised circuits. Input points have both a
physical state and a software state, as described below:
Physical State
Input points have physical states of OPEN and CLOSED. An open input is considered
to be in ALARM condition. A closed input is considered to be in NORMAL
condition.
Software State
Input points have software states of UNSHUNTED (active) and SHUNTED (not
active). When an input is unshunted, all physical changes of state (openings and
closures) are recognized. When an input is shunted, physical changes of state are
Figure 5-3.
Input Point configuration.
N-1000-III/IV Input Configurations
Input Condition
Input Status
1. Non-Supervised Normally Closed Circuit (default)
Shorted
Normal
Open
Alarm
Resistance*
Trouble
2. Non-Supervised Normally Open Circuit
Shorted
Alarm
Open
Normal
Resistance*
Trouble
3. 3-State Supervised Normally Closed Circuit
Shorted
Trouble
Open
Alarm
Resistance
Normal
4. 3-State Supervised Normally Open Circuit
Shorted
Alarm
Open
Trouble
Resistance
Normal
Normally open circuit
Normally closed circuit
Normally open circuit
input
common
input
common
input
common
Normally closed circuit
input
common
2.2 K ohm 5%
2.2 K ohm 5%
*Unusually high resistance or the presence of an EOL resistor will result in a trouble status.