Honeywell Vertex M Technical Handbook page 44

Vertex M 24-Point Continuous Monitor
TM
All events require User Ack
When selected, non-latching alarm
events will not be removed from the
event list until an authorized user
acknowledges the event. Fault and
latching alarm events are not affected
by this option, since an authorized
user must reset these events and a
reset also serves as an acknowledgement.
Section 3 - Startup
Non-Latching Gas Alarm Relays
A latching gas alarm relay activates when a
gas concentration reaches a level 1 or
level 2 alarm setting. The relay remains
activated until an authorized operator resets
the alarm. Non-latching gas alarm events
clear themselves as soon as the gas
concentration drops below the alarm setting.
Inverted Gas Alarm Relays
Vertex M alarm relays, by default, are normally open (de-energized)
when no alarm condition exists. If this option is checked, the alarm
relays will be normally closed (energized) when there is no alarm.
Fault relays are not affected by this option and are always normally
closed (energized) unless a fault condition exists.
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