Page 13
Stratos-Micra • INSTALLER’S HANDBOOK • Iss. 1
6
3.27 Reference level –
Referencing
tab
The value set with this function is the percentage reference signal subtracted from the
detector’s signal, if a reference device has been allocated. The default value is 0.
3.28 Reference back-off –
Referencing
tab
This value is the delay time between a build up of pollution being seen by the reference
(if used) and the pollution being seen by the detector. The default value is 15.
3.29 Flow rate –
Flow monitoring
tab
This function is for display purposes only, and shows a value corresponding to the cur-
rent airflow through the detector.
3.30 Flow high limit –
Flow monitoring
tab
This value is the level above which airflow needs to increase to trigger a fault indication
(which may indicate a loose or damaged inlet pipe).
Flow low limit
and
Flow high limit
parameters are automatically set up on
initial power-up at the end of FastLearn. They can be manually adjusted after that if
required.
3.31 Flow low limit –
Flow monitoring
tab
This value is the level below which airflow needs to be reduced to trigger a fault read-
ing (which may indicate a blocked pipe).
Flow low limit
and
Flow high limit
parameters are automatically set up on
initial power-up at the end of FastLearn. They can be manually adjusted after that if
required.
3.32 Flow fault delay –
Flow monitoring
tab
This feature requires the Remote Control Software version 3.2 or later, available to
download free on www.airsensetechnology.com
The default flow fault thresholds on the Stratos-Micra are set to meet the stringent
airflow monitoring requirements of EN54-20, with a default flow fault delay of 30 sec-
onds. This may lead to unwanted flow faults being generated when local conditions
cause short-term variations in airflow. To help alleviate such issues, the flow fault delay
is programmable from 30 to 240 seconds. The flow level needs to be above the high
flow threshold or below the low flow threshold throughout the delay period for a fault
to be generated.
NB: When setting the value of this function, it is important to take into account
that the control unit (e.g. fire panel) may not react immediately to a trouble sig-
nal being generated by the detector, and this will add to the total fault response
time of the system.
The function value must be chosen so that the total time between the detector
entering a fault condition and a fault signal being generated by the panel meets
the requirements of local or national fire regulations. The maximum allowable
response time for EN54-20 compliance is 300 seconds, and that for NFPA 72 com-
pliance is 200 seconds.
As an example: in the latter case, if the flow fault delay were set to 180 seconds
(within the limit), but the fire panel did not generate a fault indication for another
25 seconds, the total response time of 205 seconds means the system would not
comply with the regulations.