The “Select Filter” menu is used for adjusting the f ilter mode , of which, there are three modes. The correct and
default setting is “2”. This is a factory authorized adjustment.
3.7 C
ALIBRATION
NOTE: Before calibration, verify the range setting as described in section 3.6.4.
Material Requirements
*
Detcon PN 3270 MicroSafe™ Programming Magnet
*
Detcon PN 6038 Threaded Calibration Adapter
*
Span gas containing the H2S gas in air. Nitrogen mixtures are not acceptable. H2S gas concentration is recom-
mended at 25 ppm (which is the factory default for ranges 0-50 ppm and 0-100 ppm) or 10 ppm (which is the
factory default for the range 0-20 ppm) at a controlled f low rate of 200 to 500 ml/min. Other concentrations
can be used as long as they fall within allowable levels. See section 3.7.2 for details.
*
Detcon PN 985-241100-321 In-Line Humidifying Tube.
NOTE: Span gas bottles contain 0% humidity and this ultra-low humidity condition will cause inaccurate readings
when used to calibrate a sensor. To prevent this error, Detcon prescribes the use of an In-Line Humidifying Tube,
which adds the relative humidity to the span gas. The humidifying tube is not necessary when using a gas generat-
ing calibration device that consists of pumped ambient air and an H2S generating source.
3.7.2 Calibration Procedure - Span
CAUTION:
Verif ication of the correct calibration gas level setting and calibration span gas concentration is
required before “span” calibration. These two numbers must be equal.
Calibration consists of entering the calibration function and following the menu-displayed instructions. The display
will ask for the application of span gas in a specif ic concentration. This concentration is equal to the calibration gas
level setting. The factory default setting for span gas concentration is 10 ppm for the range 0-20 ppm and 25 ppm
for the ranges 0-50 ppm and 0-100 ppm. If a span gas containing the prescribed default concentration is not avail-
able, other concentrations may be used as long as they fall within 10% and 50% of full-scale range. However, any
alternate span gas concentration value must be programmed via the calibration gas level menu before proceeding
with span calibration. Follow the instructions below for span calibration.
a)
Verify the current calibration gas level setting as indicated by the programming status menu. To do this, follow
the instructions in section 3.8 and make note of the setting found in listing number 2. The item appears as
“CalLevel @ xxPPM”.
b)
If the calibration gas level setting is equal to your calibration span gas concentration, proceed to item “f”. If
not, adjust the calibration gas level setting so that it is equal to your calibration span gas concentration, as
instructed in items “c” through “e”.
c)
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. At this point you can scroll
through the programming menu by momentarily waving the programming magnet over “PGM 1” or “PGM 2”.
The menu options are: View Program Status, Set Cal Level, Set Heater Level, Set Range, and Linearize Sensor.
d)
From the programming menu scroll to the calibration level listing. The menu item appears as:
“SET CAL
LEVEL”.
Enter the menu by holding the programming magnet stationary over “PGM 1” for 3 seconds until
the display reads
“CalLevel @ ##PPM”
, then withdraw the magnet. Use the programming magnet to make
an adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the reading is equal to
the desired calibration span gas concentration. Exit to the programming menu by holding the programming
magnet over “PGM1” for 3 seconds.
e)
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.
f)
Enter the calibration span menu by holding the programming magnet stationary over “PGM 1” for 3 seconds
The display will read
“1-SPAN 2-EXIT”
Hold PGM 1 for 3 seconds to proceed with a span or hold PGM 2
for 3 seconds to exit back to normal operation mode. After choosing span you may, within 1 minute, abort the
span procedure by a 3 second hold on PGM 2.
Detcon Model TP-524C Hydrogen Sulfide Sensor
PG.13
