Detcon FP-524HT - Manual (Page 6)

3.2 A PPLICATION
Model FP-524HT MicroSafe™ sensors are designed to detect and monitor combustible gas in ambient air in the range
of 0-100% LEL. Minimum sensitivity and scale resolution is 1%. Operating temperature range for transmitter electronics
is -40° to +175° F; -40° to +75°C . Operating temperature range for Sensor Head of this HT version is 40° to +302° F; -40°
to +150°C. It is expected that anyone purchasing this unit will be remote mounting the HT Sensor Head from transmitter and
placing sensor in a very high temperature location. While the sensor is capable of operating outside these temperatures,
performance specifications are verified within the limit.
3.2.1 Sensor Placement/Mounting
Sensor location should be reviewed by facility engineering and safety personnel. Area leak sources and perimeter mounting
are typically used to determine number and location of sensors. The sensors are generally located 4-6 feet above grade.
3.2.2 Response to Different Gases
An attractive feature of the catalytic detector elements is their almost universal response to lower explosive limits of
virtually any combustible gas. Most detectable gases produce a similar output, however the signal amplitudes differ.
The table in section 3.7 lists theoretical factors (K factors) for different gases which are a measure of their signal
amplitude as compared to methane which has a K factor of 1.00. Since these factors are theoretical, they will only
give a guide to the response expected from other gases. The Model FP-524HT sensor can be conf igured to detect
any of the listed gases. The gas selected for detection is referred to as the target gas. The sensor can also be conf ig-
ured to allow the user to calibrate with a listed gas other than the target gas. This selection is referred to as the cali-
bration gas. Unless otherwise specif ied, Model FP-524HT sensors are conf igured to detect methane and are calibrat-
ed with methane to a scale of 0-100% LEL. Refer to section 3.7 for details.
3.3 S PECIFICATIONS
Method of Detection
Catalytic detector diffusion/adsorption
Measurment Range
0-100% (lower explosive limit) LEL
Accuracy/Repeatability
± 3% LEL in 0-50% LEL Range
± 5% LEL in 51-100% LEL Range
Response/Clearing Time
T50 <10 seconds; T90 <30 seconds
Zero Drift
< 5% per year
Operating Temperature Range
-40° to +175° F; -40° to +75°C (Transmitter electronics)
-40° to +302° F; -40° to +150°C (Special HT Sensor Head)
Operating Humidity Range
0-99% non-condensing
Output
Linear 4-20 mA DC
Input Voltage
11.5-28 VDC
Power Consumption
1.9 watts @ 24V
Electrical Classification
Explosion Proof; Class I; Div. 1; Groups B, C, D
Sensor Warranty
2 year conditional
3.4 O PERATING S OFTWARE
Operating software is menu listed with operator interface via the two magnetic program switches located under the
face plate (reference f igure 6). The two switches are referred to as “PGM 1” and “PGM 2”. The menu list consists of
3 items which include sub-menus as indicated below. (Note: see the last page of this manual for a complete software
f low chart.)
Model FP-524HT Combustible Gas Sensor PG.6