Thermo Fisher Scientific CyberScan CON 11/CON 110 - Manual (Page 78)

Instruction Manual CON 11/110
74
18 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
NOTE: A controlled temperature water bath is ideal for this procedure
1. Immerse the electrode into a sample of your solution and adjust the temperature
coefficient to 0% (that is, no compensation) by performing the following:
2. From measurement mode, press the SETUP key to enter Setup menu.
3. Press the MI/S or MR/T key until the lower display reads P7.0.
4. Press the HOLD/ENTER key to display the temperature coefficient value.
5. Press the MR/T key until the upper display shows 0.0.
6. Press HOLD/ENTER key to confirm the value.
7. Press CAL/MEAS key to return to measurement mode.
8. Wait for 5 minutes. Note T
1
and C
T1
(conductivity at T
1
).
9. Condition the sample solution and electrode to a temperature (T
2
) that is about 5
°C to 10 °C different from T
1
, and note the conductivity reading C
T2
.
NOTE:
Record your results for future reference. Ideally T
1
and T
2
should bracket your
measurement temperature, and should not differ by more than 5 °C.
10. Calculate the temperature coefficient of your solution using the formula shown
above.
11. Enter the temperature coefficient you calculated into the meter by following the
following steps.
12. From measurement mode, press the SETUP key to enter Setup mode.
13. Press the MR/T key until the lower display reads P7.0.
14. Press the HOLD/ENTER key to show the temperature coefficient value (should be
0, as per step 1 above).
15. Press the MI/S key until the upper display shows your calculated temperature
coefficient.
16. Press HOLD/ENTER key to confirm the value.
17. Press CAL/MEAS key twice to return to measurement mode.
The calculated temperature coefficient will not be applied to all the meter readings.