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7-47
D-620003-0-20 Rev J
CONFIDENTIAL
Connecting Contact Alarms to a Unison System
7.7.2.1
Expansion Hub Alarm Sense (UNS-EH-2 only)
The Expansion Hub can sense three external contact closure alarms. These contact
closure inputs were designed for monitoring an Uninterruptible Power Supply (UPS),
but could monitor any external event that provides the proper input level.
These contact closure inputs are user programmable for enable/disable and normally
open/normally closed definition. The factory default is disabled/normally closed for
all three contacts. Use AdminManager to enable and set the appropriate NO/NC state.
If a contact event alarm is detected, the Expansion Hub reports the alarm condition to
the Main Hub as a warning condition. The Expansion Hub front panel LEDs do not
indicate a contact event alarm. Use AdminManager or OpsConsole to determine the
exact alarm event.
The expansion Hub supplies 5V. If the contact is open at the external device, the
Micro reads 5V. When the contact is closed at the external device-the micro reads 0V
or Ground.
Table 7-10
Pin Connections
Table 7-11
Input Electrical Characteristics
DB9 Pin #
Connection
Signal Name
1
N/C
N/A
2
+5V through a 10K Ohm resistor. Input to
micro controller
ALARM3
3
+5V through a 10K Ohm resistor. Input to
micro controller
ALARM1
4
GND
N/A
5
+5V through a 10K Ohm resistor. Input to
micro controller
ALARM2
6
N/C
N/A
7
N/C
N/A
8
GND
N/A
9
GND
N/A
Parameter
Description
Specification
Rmin
Loop resistance for “OFF” condition
> 20k Ohm
Rmax
Loop resistance for “ON” condition
< 2k Ohm
T on Max
Max Turn-on Time
5 Second
T off Max
Max Turn-Off Time
5 Second