American Dynamics ADMPCPU User Manual

MEGAPOWER CPU 

8200-0421-03, REV. G 

ADMINISTRATOR’S GUIDE 

73 of 82

 

 

An alarm is a signal generated by an external device 
connected to the MegaPower CPU system, either 
directly or through an alarm interface unit. External 
alarm signals can be generated in different ways, 
such as opening a locked door or window or 
detecting a moving object. In this guide, all types of 
alarm signals are referred to as alarm contacts. The 
system can be programmed to respond to up 4,096 
alarm contacts. 

The MegaPower CPU receives external alarm 
contact signals via RS-232 communications from 
alarm interface units and/or external computers 
emulating the alarm codes. To process alarm 
contacts, each port connected to an RS-232 alarm 
input device must be set up for Port Use of Alarm. 

All alarm response actions operate by associating 
cameras and monitors with alarm contacts. Monitors 
are referred to as “armed” when this association is 
made. When a monitor is armed for an alarm contact, 
the camera video associated with that alarm contact 
is displayed when the alarm is received. Individual 
cameras or camera Salvos, each with Preset views 
and auxiliary action, can be called automatically to 
armed monitors or armed monitor blocks in response 
to alarm receipt. 

Cameras and monitors must be armed for alarm 
response if they are to provide automatic video call-
up to monitors. This includes associating alarm 
contacts with both cameras and monitors and 
specifying an Arming Code for each monitor. 

Three steps are required to arm the system for alarm 
response: 

1.  Associating alarm contacts with cameras 

Each alarm contact must be associated with a 
camera or a camera Salvo for automatic call-up 
when an alarm is received. Each camera or 
camera Salvo can be associated with more than 
one alarm contact number, allowing multiple views 
of a scene to be called up when an alarm occurs. 

When camera Salvos are associated with alarm 
contact numbers for call-up, monitor blocks 
(groups of monitors) must be associated with the 
same alarm contact numbers to display the full set 
of cameras defined in the Salvo. 

2.  Associating alarm contacts with monitors 

Each alarm contact must be associated with a 
monitor or a monitor block for call-up when an 
alarm occurs. Each monitor or monitor block can 
be associated with more than one alarm contact 
number, allowing multiple alarms to be queued 
and sequenced on a single monitor or block of 
monitors. 

When alarm contact numbers are associated with 
monitor blocks, they must be associated with the 
first monitor of a block only. 

3.  Arming the Monitors (see APPENDIX H: Monitor 

Arming Methods for detailed information) 

Monitors are armed using a monitor arming code 
that identifies the following: 

•  Alarm Display Method (either Single, Block, or 

Dual). 

•  Alarm Queuing Method (either Sequence or 

Hold). 

•  Alarm Clearance Method (either Instant, Auto, 

or Manual). 

Multiple alarm arming methods may be used to 
provide flexible responses to alarms. 

During the period in which an alarm is active and 
being displayed on an armed monitor, the monitor 
status line shows the uppercase word “ALARM.” If a 
camera Salvo is called in response to an alarm, the 
monitor displaying the first camera of the Salvo 
shows the word “ALARM” in its status line and 
monitors displaying the remaining cameras of the 
Salvo show the word “SALVO” in their status lines.