Thermo Fisher Scientific CyberScan PC 510 - Manual (Page 53)

Instruction Manual PC 510
49
17 ADDENDUM 4: CALCULATING TEMPERATURE COEFFICIENTS
To determine the temperature coefficient of your sample solution use this formula:
C
T2
– C
T1
tc = 100 x
C
T1
(T
2
– 25) – C
T2
(T
1
- 25)
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 probe into a sample of your solution and adjust the temperature coefficient to 0%
(that is, no compensation) by performing the following:
A. From measurement mode, press the SETUP key to enter Setup mode.
B. Press the or key until the lower display reads P8.0.
C. Press the ENTER key twice. The lower display reads tCO and the upper display shows the
temperature coefficient value.
D. Press the key until the upper display shows 0.0.
E. Press ENTER key to confirm the value.
F. Press CAL/MEAS key twice to return to measurement mode
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
.
NOTE: Record your results for future reference. Ideally T
1
and T
2
should bracket your
measurement temperature, and should not be different by more than 5
°C.
4. Calculate the temperature coefficient of your solution according to the formula shown above.
5. Enter the temperature coefficient you calculated into the meter.
A. From measurement mode, press the SETUP key to enter Setup mode.
B. Press the key until the lower display reads P8.0.
C. Press the ENTER key twice. The lower display reads tCO and the upper display shows the
temperature coefficient value (should be 0, as per step 1 above).
D. Press the key until the upper display shows your calculated temperature coefficient.
E. Press ENTER key to confirm the value.
F. Press CAL/MEAS key twice to return to measurement mode.
The calculated temperature coefficient will not be applied to all the meter readings.