20 Note: This document is based on the recommendatio ns of BS5839 Part 1: 2002. I t is intended only as a guide to the ap plication of fire detection systems.
Reference must be made to relevant national and local stan dards.
DRIFT COMPENSATION AND SMOOT HING
Drift Compensation and Smoothing eliminate nuisance
alarms and provide a consis tent progressive alarm sensitivity
threshold throughout the pe riod between servic e intervals.
In many instances this will result in an improved eco nomic
performance through saving s in the cost of maint enance by
extending the detector clea ning interval.
Intelligent sensors incorpor ate enhanced digital si gnal
processing, eliminating spurious peaks.
5251REM, 5251EM AND 5251HTEM HEAT SENSORS
The 5251 range of static element and “rate o f rise”
temperature sensors provide solut ions for a wide range of
applications.
The 5251EM and 5251HTEM are fixed temperature analo gue
addressable sensors employing low mass t hermistors and
microprocessor technology for fa st response and linear
temperature sensing. Their linear respo nse allows these
sensors to be used to signal temperature s over the range of
58°C (Class A1S) to 78°C (Class BS ).
The 5251REM uses the same thermistor and microp rocessor
technology to provide an alarm when the rat e of rise
in temperature exceeds 10°C/minute (t ypical) or if the
temperature exceeds a threshold of 58°C ( Response Class
A1R).
5251REM is approved to EN54-5: 20 00 Class A1R
5251EM is approved to EN54-5: 200 0 Class A1S
5251HTEM is approved to EN54-5: 2 000 Class BS
Specifications
Height: 51mm in B501 Base
Weight: 102g excluding base
System Sensor Intelligent Product Range
Processed versus Unprocessed Signals
Time: hours
Processed
Unprocessed
PW4 µs
Effects of Drift Compensation
Time: years
Sensor value
Low fault threshold
Analogue sensor value
Maintenance levels
Adjusted thresholds