Section V. Alarms
V. Alarms
A.
Definition
Alarms are annunciated anytime something occurs that requires immediate operator attention. This could be
a sensor reading outside of its normal operating range, or a switch changing from its normal position. The
PMS II will first detect the situation, then monitor it for a pre-determined period of time to see if it is
momentary, and alarm if it persists.
B.
Unacknowledged Alarms
Unacknowledged alarms are annunciated in four ways; (1) The monitor will automatically display an alarm
summary page with the parameter in alarm being displayed in bright (double intensity) characters and
flashing, (2) the bar or switch block on the normal page display is made bright (double-intensity) and starts to
flash, (3) the key for the page on which the alarm is located starts flashing red, and (4) the keyboard audible
alarm and the main system alarm relay are turned on. An unacknowledged alarm display (double-intensity
and flashing) will remain until the alarm is acknowledged, even if the point returns to normal in the
meantime. This ensures the cause for the alarm will be observed.
C.
Acknowledged Alarms
An Acknowledged Alarm is indicated by a display which is double-intensity, but not flashing. The operator'
can acknowledge an unacknowledged alarm displayed on the screen by pressing the ACK (acknowledge)
key. This will cause all the unacknowledged alarm displays on the page to stop flashing (become
acknowledged alarm displays) and turn off the main system alarm relay and the audible alarms on all the
Operator's Stations. Should there be other alarms on other pages (as indicated by other flashing keys), the
operator should press the flashing key to cause the alarming indication to be displayed, notice which displays
are flashing, and press the ACK (acknowledge) key. Acknowledged alarms will remain double-intensity until
the condition that caused them returns to normal. The PMS II guards against repeated alarms from a sensor
reading near a setpoint by requiring that readings return well within the normal range before cancelling the
alarm. For this reason, it is sometimes possible to see bars near a setpoint which are within the normal
range, yet still double-intensity.
D.
Silenced Alarms
Operator's Stations may be configured with a SILENCE key in place of an ACK key. These stations are to be
installed in the workstations of personnel meant to be informed of alarms, but not responsible for
acknowledging or correcting them. When an unacknowledged alarm is annunciated, the audible alarms of all
stations and the main alarm relay are turned on. The operator may silence his individual station audible
alarm by pressing the SILENCE key. The main system alarm relay, the audible alarms at
PMS II Operator's Instructions
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