Detcon FP-524HT - Manual (Page 12)

face plate. DO NOT remove the glass lens cover to calibrate or change programming parameters. Two switches
labeled “PGM 1” and “PGM 2” allow for complete calibration and programming without removing the enclosure
cover, thereby eliminating the need for area de-classif ication or the use of hot permits.
A magnetic programming tool (see f igure 5) is used to operate the switches. Switch action is def ined as momentary
contact, 3 second hold, and 30 second hold. In momentary contact use, the programming magnet is waved over a
switch location. In 3 second hold, the programming magnet is held in place over a switch location for 3 or more
seconds. In 30 second hold, the programming magnet is held in place over a switch location for 30 or more sec-
onds. Three and thirty second hold is used to enter or exit calibration and program menus while momentary con-
tact is used to make adjustments. The location of “PGM 1” and “PGM 2” are shown in f igure 6.
NOTE: If, after entering the calibration or program menus, there is no interaction with the menu items for more
than 30 seconds, the sensor will return to its normal operating condition.
3.7 T
ARGET
G
AS AND
C
ALIBRATION
G
AS
S
ELECTION
Because of the catalytic detector elements almost universal response to lower explosive limits of combustible gas,
the FP-524HT sensor can be conf igured to specif ically detect any of the combustible gases listed in table 1. This
specif ic gas is referred to as the “target gas”. In addition, the sensor can be conf igured so that it can be calibrated
with any of the listed gases, regardless of which target gas is selected. This gas is referred to as the “calibration gas”.
These two features allow a signif icant degree of f lexibility in the detection and calibration process.
Unless otherwise specif ied at time of order, Model FP-524HT combustible gas sensors are conf igured to detect
methane gas in the range 0-100% LEL and are calibrated with 50% LEL methane in air. In this conf iguration,
methane is chosen as both the target gas and the calibration gas.
CAUTION:
Verif ication of specif ic target gas and calibration gas settings is required before commissioning.
To verify target gas and calibration gas settings, or to reconf igure the target gas or calibration gas, follow the
instructions below.
3.7.1 The “K” Factor
Most detectable gases, as listed in table 1, produce a similar output, however the signal amplitudes will differ. This
difference in amplitude is ref lected by a numeric f igure known as a “K factor”. The K factors are referenced to
methane which has a K factor of 1.00. It should be noted that these factors are theoretical and should only be used
as a guide to the response expected from other gases.
Model FP-524HT Combustible Gas Sensor PG.12
Magnetic Programming Tool
Figure #5
detcon inc.
Program Switch #2
FLT CAL
MicroSafe™ LEL Gas Sensor
HOUSTON, TEXAS
PGM 2
PGM 1
MODEL FP-524C
CONTRAST
Fault & Cal LEDs
Program Switch #1
Menu Driven Display
Plug-in Microprocessor Control Circuit
Display Contrast Adjust
Figure #6