DM-634C Oxygen Sensor Assembly
DM-634C O2 Sensor Instruction Manual Rev. .066
Page 13 of 25
3.6
Start Up
Upon completion of all mechanical mounting and termination of all field wiring, apply system power and
observe the following normal conditions:
a)
“Fault” LED is off.
b)
A temporary upscale reading may occur as the sensor powers up. This upscale reading will clear to
about 20.9% within a few minutes of turn-on, assuming there is no oxygen deficient condition in the
area of the sensor.
Note:
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.
Initial Operational Tests
After a warm up period has been allowed for, the sensor should be checked to verify reliable sensitivity
to O2 gas.
Material Requirements
*
Detcon P/N 6132 Threaded Calibration Adapter
*
Test gas containing 100% nitrogen at a controlled flow rate of 500 ml/min.
a)
Attach the calibration adapter to the threaded sensor housing. Apply the test gas at a controlled flow
rate of 500 ml/m. Observe that the LCD display decreases to a level of 3% or less.
b)
Remove the test gas and observe that the LCD display increases back to 20.9% ±2% of scale (0.5%
O2).
c)
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 O2 gas sensors are pre-calibrated prior to shipment and will, in
most cases, not require significant adjustment on start up. However, it is recommended that a complete
calibration test and adjustment be performed within 24 hours of installation. Refer to calibration instructions in
later text.
3.7
Calibration
Material Requirements
* Detcon PN 327-000000-000 MicroSafe™ Programming Magnet
* Detcon PN 613-120000-000 Threaded Calibration Adapter
* Test gas containing 100% nitrogen at a controlled flow rate of 500ml/min.
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-classification or the use of hot
permits. A magnetic programming tool (see Figure 11) is used to operate the switches. Switch action is defined
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 seconds. Three and thirty second hold is used to enter or exit calibration and program
menus while momentary contact is used to make adjustments. The location of “PGM 1” and “PGM 2” are
shown in Figure 12.
