Nova-Tech pH-Dissolved Oxygen Meter - Manual (Page 8)

Dissolved Oxygen calibration in percent saturation
You can calibrate this meter quickly and easily in air. The exact calibration value
depends on barometric pressure. The meter is set to a factory default of 760 mm Hg,
which results in a calibration value of 100% saturation in air.
NOTE: If the barometric pressure setting has been changed from 760 mm Hg, the
calibration value in air will automatically adjust to a value other than 100%.
The adjusted value will be correct for the new barometric pressure setting.
• See page 39 to change the pressure setting.
• See Appendix 2 on page 67 for a chart of adjusted % saturation values.
15 14
To calibrate 100 % saturation:
1. Rinse the probe well with deionized
rinse water or rinse solution. For best
accuracy, wrap the end of the probe
in a damp cloth. Do not touch the
membrane.
2. Press the MODE key to select the
% saturation mode.
See figure
3. Press the CAL key. The CAL indicator
will appear above the primary display.
The primary display shows the current
value of the measurement and the
secondary display will show 100.0
(see NOTE above).
See figure
4. Hold the probe in the air (or in damp
cloth). Wait for the reading to stabilize.
If the Ready indicator feature is enabled,
it will appear when the reading is stable
(see page 43 for Ready indicator setup).
5. Press the ENTER key. The meter auto-
matically calibrates to 100.0% air satura-
tion and returns to Measurement mode.
See figure
ATC
READY
MEAS
%
C
READY
CAL
%
ATC
READY
MEAS
%
C
4.5
A
A
B
C
B
C
Notes
The reading in the primary display in step 3 must read at 50% or above for the
calibration to work correctly. Whenever an error occurs during calibration, the
ERR indicator appears in the lower left hand corner of the display.
You can offset your % DO calibration: see page 40 for directions.
Preparing the meter for DO calibration
Before calibrating your meter, make sure to rinse
the DO probe well with de-ionized water or rinse
solution.
NOTE: Do not let membrane surface of the DO
probe touch any other surface. The DO
probe guard (the piece with holes fitted
over the end of the probe) protects the
membrane; make sure this is always
attached to the probe while it is in use.
You can calibrate for dissolved oxygen in either
% saturation or mg/l (ppm). All new DO
calibrations automatically override existing
DO calibration data.
Before Dissolved Oxygen calibration
Before starting DO calibration, make sure you are in
the correct measurement mode. When you switch
on the meter, the meter starts up in the units last
used (either pH, mg/l, ppm, % saturation). For
example, if you shut the meter off in “mg/l” units,
the meter will read “mg/l” units when you switch
the meter on.
NOTE: Most users will calibrate to 100% saturation
even when working in mg/l. When calibrat-
ing the meter in mg/l mode, you can make
fine adjustments, typically to a midrange
value between 10 and 100%. If you are
calibrating to a midrange value, you need
to set the 100% saturation value first.
4.4
DO Probe guard
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