EUTECH INSTRUMENTS CD 650, Instruction Manual

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3. Calibration Mode For All Meters
3.1 About Calibration
The 600 series meters are factory calibrated and allows you to measure
pH/mV/ion/conductivity/resistivity/TDS/salinity/DO(%)/DO(mg/L) respective to
the model(s) you have purchased. Calibrate to all measurement ranges to
ensure the highest accuracy in any given measurement range. This should be
done before you make measurements for the first time and also each time a
new electrode is attached to the meter or when you suspect that the
meter/electrode is out of calibration.
3.2 About Conductivity/ Resistivity/ TDS/ Salinity Calibration
Before measuring conductivity, resistivity, TDS or salinity, you will need to
calibrate the meter with known conductivity, resistivity, TDS or salinity values.
The meter is capable of performing either automatic or manual calibration.
In the automatic calibration mode, the meter automatically detects and verifies
the appropriate known calibration standards solutions being calibrated before
accepting these particular calibration standards as one of its calibration values
in a specific measurement range. This automatic calibration mode frees you
from cumbersome calibration procedure.
The meter can perform a single- or multi-point calibration. You will need to set
your meter to single- or multi-point calibration in the Setup mode for
conductivity, resistivity, TDS or salinity.
Refer to the setup section for the particular mode you will be measuring. Instead
of calibrating for TDS directly using TDS calibration standard solutions, you can
have TDS calibration by using the conductivity calibration method and enter the
appropriate TDS conversion factor into the meter.
For more information regarding TDS Conversion Factor determination, please
go to the ‘Appendix’ of this manual.
3.3 Preparing the Meter for Calibration
Before starting calibration, make sure the meter is in the appropriate
measurement mode.
For pH
Connect the pH probe to the BNC connector of the meter.
Be sure to remove the protective electrode storage bottle or rubber cap of the
electrode before calibration or measurement. If the electrode has been stored
dry, wet the electrode in clean water for 10 minutes before calibrating or taking
readings to saturate the pH electrode surface and minimize drift.
Wash your electrode in clean water after use, and store in electrode storage
solution. If storage solution is not available, use pH 4.01 or 7.00 buffer solution.
Do not reuse buffer solutions after calibration. Contaminants in the solution can
affect the calibration, and eventually the accuracy of the measurements.