Detcon DM-534C - Manual (Page 16)

DM-534C Oxygen Sensor Assembly
DM-534C O2 Sensor Instruction Manual Rev.1.4 Page 12 of 18
NOTE 1: If the circuitry is unable to adjust the span to the proper setting the sensor will
enter into the calibration fault mode which will cause the display to alternate between the
sensor’s current status reading and the calibration fault screen which appears as: “CAL
FAULT” (see section 3.7.3)..
8.2 Additional Notes
1. Upon entering the calibration menu, the 4-20 mA signal drops to 2 mA and is held at this level until
you return to normal operation.
2. If during calibration the sensor circuitry is unable to attain the proper adjustment for span, the sensor
will enter into the calibration fault mode and cause the display to alternate between the sensor’s
current status reading and the calibration fault screen which appears as: “CAL FAULT” If this occurs
you may attempt to recalibrate by entering the calibration menu as described in section 3.7.1a. If the
sensor fails again, defer to technical trouble shooting.
8.3 Calibration Frequency
In most applications, monthly to quarterly calibration intervals will assure reliable detection. However,
industrial environments differ. Upon initial installation and commissioning, close frequency tests should be
performed, weekly to monthly. Test results should be recorded and reviewed to determine a suitable
calibration interval.
8.4 Calibration Gas Level
Calibration consists of entering the calibration function and following the menu-displayed instructions. The
default calibration gas level is 20.9% O2. The sensor however can be programmed to other calibration gas
levels as long as they fall within the range of 15.0% to 25.0%. If this is the case, during span calibration the
display will ask for the application of span gas in the same concentration as the calibration gas level setting.
Follow the instructions below for span calibration at settings other than 20.9%.
a) Verify the current calibration gas level setting as indicated by the programming status menu. To do
this, follow the instructions in section 8.0 and make note of the setting found in listing number 2. The
item appears as “CalLevel @ xx.x%”
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 30
seconds until the display reads “VIEW PROG STATUS”, and 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, and Set Cal Level.
d) From the programming menu scroll to the calibration level listing. The menu item appears as: “ SET
CAL LEVEL”
e) Enter the menu by holding the programming magnet stationary over “PGM 1” for 3 seconds until the
display reads “CalLevel @ xx.x%”, and 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.
f) Exit back to normal operation by holding the programming magnet over “PGM 2” for 3 seconds, or
automatically return to normal operation in 30 seconds.