Nova-Tech DO 6+ - Manual (Page 14)

Instruction Manual DO 6+
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3. CALIBRATION
3.1 General Information
The DO 6+ has three measurement modes; DO as % saturation, DO as mg/L
(or ppm) concentration, and temperature.
Dissolved oxygen levels vary with temperature, barometric pressure, and
salinity, so calibration must be performed with consideration of these factors. It
is necessary to set the proper temperature, barometric pressure and
salinity values prior to performing any DO calibration or measurement.
See Section 3.2 — Temperature Calibration
See Section 5.2 — Automatic Temperature Compensation.
See Section 5.9 — Pressure & Salinity Adjustment.
The DO 6+ will accept two % saturation calibration points; 100% using
saturated air or air-saturated water, and 0% using zero oxygen solution. When
100% calibration is performed, the corresponding concentration is adjusted
simultaneously. Therefore, it is not necessary to calibrate the concentration
mode. If calibrating for 0% oxygen, note that the meter will take several minutes
to reach 0% saturation value and constant stirring is not required.
The following table lists calibration values in % saturation calibration mode with
two different barometric pressures. Note that the saturation value (92.1%) has
decreased due to the lower barometric pressure entered.
% Saturation (per
factory default value)
Calibration Value
(760mmHg)
Calibration Value
(700mmHg)
less than 10% 0% 0%
10.1% to 49.9% Err.1 (error 1) Err.1 (error 1)
50% to 200% 100% 92.1%
If calibration is attempted from 10.1% to 49.9%, the “Err.1” message is shown—
calibration is rejected and the display will return to measurement mode.