10
Table 4.A.
Alarm point polarity descriptions
Discretes 1–16
Relays**
Analogs 1–2
B* A*
B* A*
NC NO CO
+
–
+
–
ALM 1
1 26
ALM
14
14 39
Relay 1
42 17 43
Analog
1
A B 23 48
ALM 2
2 27
ALM
15
15 40
Relay 2
44 19 18
Analog
2
A B 24 49
ALM 3
3 28
ALM
16
16 41
Fuse
Alarm***
20 45
ALM 4
4 29
ALM 5
5 30
ALM 6
6 31
ALM 7
7 32
ALM 8
8 33
ALM 9
9 34
ALM
10
10 35
ALM
11
11 36
ALM
12
12 37
GND
25 50
ALM
13
13 38
*
The polarity of alarm point A is negative and alarm point B is positive.
** NO=Normally Open, NC=Normally Connected, CO=Common
*** A contact closure will occur when the fuse is blown.
4.7.1 Discrete Alarms
Contact to Ground
- Batt.
AL 1A
AL 1B
Dry Contact
- Batt.
AL 1B
AL 1A
NetGuardian case
NetGuardian case
Note: Make sure that grounds have a common reference
usually accomplished by tying grounds together.
Fig. 4.11.
Discrete alarm points can connect as a dry contact or a contact to ground
The NetGuardian 216 supports up to 16 discrete alarm inputs. Discrete alarms are typically used to monitor door
alarms, power outages, equipment failures, and other on/off conditions.
Discrete alarm points connected to the NetGuardian are single-lead signals referenced to ground. The B side of
each alarm point is internally wired to ground, so either a single wire bringing a contact to ground or a dry closure
