Detcon TP-624C - Manual (Page 13)

Note 1: All alarms will be disabled for 1 minute after power up. In the event of power failure, the alarm disable
period will begin again once power has been restored.
Note 2: If the display contrast needs adjustment, refer to section 3.12.
Note 3: If the sensor has been installed using the remote mounting conf iguration as described in section 3.5.6, the
sensor heater voltage must be adjusted after initial power up. If this is the case, f irst adjust the heater voltage as
described in section 3.6.2, then proceed with the initial operation tests below (section 3.6.1).
Note 4: The 4~20mA signal will be held at 4mA for the f irst two minutes after power up.
3.6.1 Initial Operational Tests
After a warm up period has been allowed for, the sensor should be checked to verify sensitivity to H2S gas.
Material Requirements
* Detcon PN 6038 Threaded Calibration Adapter
* Span Gas 25 ppm H2S in air at a controlled f low rate between 200 and 500 ml/min (or 10 ppm for 0-20 ppm
range - see section 3.6.4 for more information on ranges). NOTE: Do not use H2S and nitrogen gas mixtures.
* Detcon PN 985-241100-321 In-Line Humidifying Tube
a) Attach the Perma-Pure tubing inline with the tubing between the Cal Gas Cylinder and the sensor. The humid-
ifying tube will introduce the ambient relative humidity into the Cal Gas as it passes through the tube.
b) Attach the calibration adapter to the threaded sensor housing. Apply a the test gas at a controlled f low rate of
200 to 500 ml/m (200cc/min is the recommended f low). Observe that the LCD display increases to a level of
10-25 ppm or higher (or 5-10 ppm for 0-20 ppm range).
c) Remove the test gas and observe that the LCD display decreases to “0 PPM H2S” .
d) If alarms are activated during the test, and have been programmed for latching operation, reset them according to
the instructions in section 3.9.2.
Initial operational tests are complete. Detcon H2S gas sensors are pre-calibrated prior to shipment and will, in most
cases, not require signif icant adjustment on start up. However, it is recommended that a complete calibration test
and adjustment be performed 16 to 24 hours after power-up. Refer to calibration instructions in later text.
3.6.2 Remote Mount Heater Voltage Setup
If the sensor has been installed using the remote mounting conf iguration as described in section 3.5.6, the sensor
heater voltage must be adjusted after initial power up. Replacement of the sensor will also require readjusting the
heater voltage. Follow the steps below to set the sensor heater voltage.
Material Requirements
* Detcon PN 3270 MicroSafe™ Programming Magnet
* Digital volt/ohm meter.
Note: Refer to section 3.6.3 for programming magnet operating instructions.
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 “Black” terminal as shown in figure 5A. Target voltage is 5.25 volts.
d) At the transmitter, enter the programming menu by holding the programming magnet stationary over “PGM 2”
for 15 seconds until the display reads “VIEW PROG STATUS” , then withdraw the magnet.
e) Next, scroll to the “SET HEATER VOLTS” listing and then hold the programming magnet over “PGM 1”
for 3 seconds. The menu item appears as “HEATER @ #.## VDC”.
f) Use the programming magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the volt-
age. Set this voltage so that the voltage measured at the remote sensor connector board is 5.25 VDC. This is the
correct voltage for an ambient temperature of 25°C at the remote sensor connector board. If ambient tempera-
ture is not 25°C reference the table in section 3.6.5 for the proper voltage setting.
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.
h) Exit back to normal operation by holding the programming magnet over “PGM 2” for 3 seconds, or automati-
cally return to normal operation in 30 seconds.
Detcon Model TP-624C Hydrogen Sulfide Sensor PG.13