3. Press the <DISABLE> key. The alphanumeric display shows the following message.
I
Press <ENTER> to DISABLE
I/O:
IOXX
I
NOTE: XX = the point to be disabled.
4. Press the <ENTER> key. The alphanumeric display shows the action taken.
I
ACTION TAKEN
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NOTE: The system indicates a trouble condition each time a point is disabled. Press the <TBL ACK> key
as required.
5. Repeat steps 2 through 4 above to disable additional points.
IMPORTANT
REPAIR/REPLACE THE FAILED CIRCUIT/DEVICE AS SOON AS POSSIBLE. ONCE REPAIRED, THE
DISABLED POINT SHOULD BE ENABLED AS SOON AS POSSIBLE. (See Section 9, How To Enable A
Disabled Point.)
TROUBLE INDICATIONS FOR TrueAlarm” SENSORS
INTRODUCTION
The devices that are used for the TrueAlarm’” operation are considered sensors instead of detectors, because these
devices do not determine alarm conditions. The TrueAlarmTM smoke sensor is a measuring device that sends data
regarding smoke density to the 4020 control panel. The TrueAlarmTM heat sensor operates in a similar fashion, but
sends temperature data instead of smoke density data. The 4020 uses this data to determine whether a trouble has
occurred. This basic operational difference is the key to TrueAlarm’” operation.
The TrueAlarm” sensor has two automatic trouble indications:
l
Dirty, and
. Excessively Dirty.
A “Smoke Detector Dirty” trouble condition is reported any time the average value on an individual sensor reaches
a set threshold value. At this time, the 4020 is still compensating for environmental factors and is holding the set
sensitivity level.
A”Smoke Detector Excessively Dirty” trouble condition is reported anytime the average value of an individual sensor
reaches a higher than threshold level. At this point, the 4020 can no longer compensate for environmental factors,
and the sensitivity level will begin to drift. Although an “excessively dirty” trouble is reported, the sensor will continue
to operate and will report an alarm condition if one is detected.
In addition to the two automatic trouble conditions, the 4020 software includes a pre-programmed digital pseudo
point (P132, Sensor Almost Dirty Log Enable) that can be turned ON at the front panel to allow a TrueAlarm” sensor
that is within 10 analog units of being a “dirty” sensor to report as if it were one. This is useful when maintenance is
being scheduled for dirty sensors, as it provides a means of seeing if other sensors are approaching a dirty state.
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