Nova-Tech 2700 Series Benchtop Meters - Manual (Page 38)

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16. Dissolved Oxygen Calibration
The DO 2700 utilizes a self-stirring polargraphic electrode with a built-in
temperature sensor. The electrode is designed for use in BOD bottles.
Power the meter on 5-15 minutes before calibration or taking a
measurement as this will allow adequate time for the electrode to warm
up. Longer warm up times are recommended when the membrane cap
and/or electrolyte in replaced—this permits the probe to use up all
oxygen retained inside the cap.
The DO 2700 has two modes; % saturation and concentration (mg/L or
ppm). In % saturation mode, the DO 2700 will accept either a one
(100%) or two point (100% & 0%) calibration. For a one point
calibration, 100% air calibration is recommended. For best accuracy
below 2.0 ppm, use zero oxygen solution to calibrate 0%. 0% calibration followed
by 100% calibration is not recommended—always perform 100% calibration first.
Always rinse the probe with clean water before and after each calibration/sample
measurement. When performing air calibration, gently shake remaining water
droplets from the probe’s membrane.
100 % Calibration
1) Power meter on with DO electrode attached for 5-15 minute warm
up.
2) Rinse the probe well with clean water then place into a BOD bottle
partially filled with water (100 mL or so).
3) Press MODE if needed for % measurement mode.
4) Press CAL. The primary reading is the current
measured value. Note: the stirrer is not
required for air calibration. For air-saturated
water calibration however, switch the stirrer
motor on (the switch is located at the top of the
electrode) during calibration and measurement.
5) Allow the reading to stabilize and lock on
100%. Press ENTER to confirm the calibration.
6) Press ESC to return to measurement mode, or continue with 0% calibration in
step 7 if desired.