General Tools and Instruments DCO1001 - Manual (Page 4)

CALIBRATION
To enter the calibration mode, turn off meter and press Ф +
simultaneously for 2 seconds. It will show blinking ppm on
the upper display and calibration value “0” at lower side.
Now the meter is running 0 ppm calibration as default.
0 ppm calibration.
The meter has a preset calibration value at 0 ppm. Put the
meter in the area free of CO and enter calibration mode. The
meter will calibrate automatically. The LCD is now display-
ing a blinking ppm value at upper side which will slowly runs
down to 0 or a minus value, completed. This takes about 10
minutes.
Note:
Don’t be alarmed if high PPM or minus value shows up when
entering calibration mode. It will go down and approach to 0
seconds. The erratic readings are caused by electromagnetic
interfere (EMI) in the environment, such as computers or cell
phones. It is suggested to remove the meter from the interfer-
ence otherwise the calibration may take much longer time or
never complete.
100ppm/500ppm calibration
For other standard calibrations press and hold to select the
calibration value. (0, 100, 500 ppm).
1. Place the meter into the sealed box filled with standard
gas
2. (e.g. 100ppm/500ppm) for 15 minutes. Then the calibra
tion will be done automatically.
3. Check if the reading meets calibration value. If it does,
the calibration is well completed. If not repeat the
procedure.
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2. F/C Switching
User can select °C or °F as the temperature mode by press
ing for temperature more than 1 sec. during Self-Test.
3. Alarm Setting
The meter is preset at the alarm value of 25 ppm to give
warnings of possible danger. Users can adjust the value for
different needs or standard by:
1. Turn off the meter.
2. Press and hold Ф until the value options show. There
will be 25, 30, 35, 45, 50, 70, 100, and 200ppm display
ing in cycles.
3. Release the button to select the preferred value.
4. The meter will return to Self- Test mode.
4. Measurements
The meter detects the existence of CO in the environment
and displays the reading in PPM. It also indicates the maxi
mum value (on the bottom LCD display) of all readings
since the meter has been on. Users may reset the maximum
value by pressing for two seconds in the measuring
mode.
5. Backlight
The meter features backlight function for using in dark
areas. Press to turn the backlight on and off.
6. Low Battery indicator
Shows on the LCD when battery voltage gets low.
Auto Power off
The meter turns itself off automatically after 15 minutes of
non-operation is disabled during calibration.