Overview of Alarms
Chapter Three: Overview
88
Alarm Conditions
An alarm condition occurs when a channel’s pressure reading goes over the alarm trip point.
When an alarm condition arises, the 146 responds in four ways. In this example, the latching
state is enabled, but the relay is initially unlatched.
1. The alarm audio tone starts. This can be quieted with the [
QUIET
/
CANCEL
] key.
2. A diamond is displayed on the left side of the front panel window, and corresponds to
one of the four red alarm letters beside it on the front panel. A diamond indicates an
alarm condition, and not the status of the alarm relays.
3. The alarm relay condition switches. That is, if a relay contact was open, it becomes
closed.
4. If the latching state for the alarm is enabled, a
LATCHED
legend appears on the left side
of the front panel window. The latched legend indicates the state of the alarm relay after
an alarm condition, not the state of the alarm condition itself. If the latching state for the
alarm is disabled, no
LATCHED
legend appears.
Note
An alarm audio tone goes off if a gauge becomes disconnected. This is
not a trip point alarm condition, and no relays are altered. To remedy the
situation, reconnect the sensor and press the [
QUIET
/
CANCEL
] key.
Here are two scenarios to further illustrate what happens in an alarm condition, and what happens
when a sensor (on an active channel) is disconnected.
Scenario 1: A Trip Point Alarm Condition
In this situation, all the relays are unlatched, and no alarm conditions are present. The alarm
latching state is enabled.
1. The pressure reading on a channel goes above the alarm trip point for that channel.
A. The alarm audio tone goes off.
B. A diamond appears in the front panel window, corresponding to a red alarm
letter on the front panel.
C. An alarm relay switches contacts (and becomes latched because of the latching
state).
D. A
LATCHED
legend appears in the front panel window.
2. Quiet the alarm audio tone by pressing the [
QUIET
/
CANCEL
] key.
A. The alarm audio tone is quieted, but the relay remains latched.
B. An alarm audio tone will go off again during the next alarm condition, regardless
of the relay latching state.
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