EUTECH INSTRUMENTS CD 650, Инструкция по эксплуатации

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Note: A controlled temperature water bath is ideal for this procedure
4. About TDS
4.1 Calculating TDS Conversion Factor
You can calibrate your meter using TDS calibration standard solutions. The
calibration standard only needs to give the TDS value at a standard temperature
such as 25 °C. To determine the conductivity-to-TDS conversion factor use the
following formula:
Factor = Actual TDS ÷ Actual Conductivity @ 25 °C
Definitions:
Actual TDS:
Value from the solution bottle label or as a standard you make using
high purity water and precisely weighed salts.
Actual Conductivity: Value measured using a properly calibrated
Conductivity/Temperature meter.
Both the Actual TDS and the Actual Conductivity values must be in the same
magnitude of units. For example, if the TDS value is in ppm the conductivity value
must be in µS; if the TDS value is in ppt the conductivity value must be in mS.
Check your factor by multiplying the conductivity reading by the factor in the above
formula. The result should be in TDS value.
4.2 Calculating Temperature Coefficients
To determine the temperature coefficient of your sample solution use this formula:
Where:
tc = Temperature coefficient 25 = 25 °C
C
T1
= Conductivity at Temp 1 C
T2
= Conductivity at Temp 2
T
1
= Temp 1 T
2
= Temp 2
1. Immerse the probe into a sample of your solution and adjust the
temperature coefficient to 0%
2. Wait for 5 minutes. Note T
1
and C
T1
(conductivity at T
1
).
3. Condition the sample solution and probe to a temperature ( T
2
) that is about
5 °C to 10 °C different from T
1
, and note the conductivity reading C
T2
.
- END OF TDS SECTION -
Note: Record your results for future reference. Ideally T
1
and T
2
should bracket
your measurement temperature, and should not different by more than 5 °C.