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Figure #7 – Detcon DM-634 User Manual

Page 14

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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

“CalGas @ ## %”, 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)

From the calibration menu

“2-SPAN” (section 3.7.1-a) proceed into the span adjust function by holding the

programming magnet stationary over “PGM 2” for 3 seconds then withdraw the programming magnet. If no

change of Span level is desired, wait 30 seconds for menu to return to normal operation. At this point the dis-

play will ask for the application of the target gas and concentration. The display reads

“APPLY xx.x %” The

xx.x here will indicate the actual concentration requested.

g)

Apply the calibration test gas at a f low rate of 500 milliliters per minute. If the calibration gas level is set at

20.9% and ambient air is verif ied to be 20.9% (normal atmospheric concentration of O2) then do nothing at

this point. The sensor will auto calibrate to ambient air O2 concentration. After 3 minutes the sensor will auto

span to the correct reading and the display will change to

“REMOVE GAS” then the display will return to

the normal operating mode.

NOTE 1: If the circuitry is unable to adjust the span to the proper setting the sensor will enter into the calibra-

tion fault mode which will cause the display to alternate between the sensor’s current status reading and the cal-

ibration fault screen which appears as:

“CAL FAULT” (see section 3.7.3).

3.7.3

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 which will activate fault alarm functions (see section 3.10) 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
3.7.1-a. If the sensor fails again, defer to technical trouble shooting.

Detcon Model DM-634 Oxygen Sensor PG.14

detcon inc.

Program Switch #2

FLT

ALM

1

CAL

MicroSafe™ O2 Gas Sensor

HOUSTON, TEXAS

PGM

2

PGM

1

ALM

2

MODEL

DM-634

CONTRAST

Alarm & Cal LEDs

Program Switch #1

Menu Driven Display

Plug-in Microprocessor Control Circuit

Display Contrast Adjust

Figure #7