Detcon FP-624C - Manual (Page 13)

3.6.1 Remote Mount Bridge Voltage Setup
If the sensor has been installed using the remote mounting conf iguration as described in section 3.5.6, the sensor
bridge voltage must be adjusted after initial power up. If this is not the case skip this section and proceed to Initial
Operational Tests. Otherwise follow the steps below to set the sensor bridge voltage.
Material Requirements
* Detcon PN 3270 MicroSafe™ Programming Magnet
* Digital volt/ohm meter.
3.6.2 Programming Magnet Operating Instructions
Operator interface to MicroSafe™ gas detection products is via magnetic switches located behind the transmitter
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 alarm level 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 6) 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 7.
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.
3.6.1 Continued - Set Sensor Bridge Voltage Procedure
a) Declassify the area around the sensor.
b) Remove the junction box cover from the remote sensor enclosure (see f igure 5A).
c) Using the digital volt/ohm meter, measure the bridge voltage at the remote sensor connector board from the
“White” terminal to the “Blue” terminal as shown in figure 5A. Target voltage is 2.7 ±0.2 volts.
d) At the transmitter, enter the programming menu by holding the programming magnet stationary over “PGM 2”
for 30 seconds until the display reads “VIEW PROG STATUS”, then withdraw the magnet.
e) Next, scroll to the “SET BRIDGE VOLTS” listing and then hold the programming magnet over “PGM 1”
for 3 seconds. The menu item appears as “BRIDGE VOLTS U/D”.
f) Use the programming magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the
bridge voltage.
g) Exit to the programming menu by holding the programming magnet over “PGM1” for 3 seconds, or automati-
cally return to the programming menu in 30 seconds.
Model FP-624C Combustible Gas Sensor PG.13
Magnetic Programming Tool
Figure #6
detcon inc.
Program Switch #2
FLT
ALM
1 CAL
MicroSafe™ LEL Gas Sensor
HOUSTON, TEXAS
PGM 2
PGM 1
ALM
2
MODEL FP-624C
CONTRAST
Alarm & Cal LEDs
Program Switch #1
Menu Driven Display
Plug-in Microprocessor Control Circuit
Display Contrast Adjust
Figure #7