LaMotte TDS 5 Meter User Manual

Page 10

TDS 5 METER

TDS Calibration

The meter is capable of up to a three-point calibration. Only one
calibration is needed for the entire range of the meter but better accuracy
will be achieved if each range is calibrated. If a range is not calibrated, the
meter will automatically calibrate to the range closest to the sample being
tested.

Calibrate the meter at least once a week if solutions with a conductivity of
less than 50 ppm are being measured in order to get +/- 2% full scale
accuracy. If solutions are being measured with conductivity in the mid
range, and the probe is washed in deionized water and stored dry, the meter
need only be calibrated once a month. Calibrate the meter at least once a
week if measurements are taken at extreme temperatures.

Select a TDS standard with a concentration near the sample to be
measured. If this is not possible, choose a value that is approximately 2/3 of
the full scale value of the measurement range. For example, in the 100 to
999 ppm range, the meter should be calibrated with a 989 ppm solution.

NOTE: The meter will not accept calibration values less than 20 ppm. All new
calibrations will automatically override existing calibrations.

Press the ON/OFF

key to turn the

meter on and to

enter the TDS

mode.

Pour approximately 3 cm of a

conductivity standard into two

separate containers.

Conductivity

Standard

3 cm

Gently stir the first

container of the

standard with the

probe. This

container will be

used as the rinse

solution to remove

contaminants.

Immerse the

probe in the

second

container of the

standard.

CAL

MODE

HOLD
ENTER

ON
OFF

Measuring the TDS of Soil

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