64
65
13. Appendix 2: Calculating Temperature Coefficients
To determine the temperature coefficient of your sample solution use this formula:
CT2 - CT1
TC
= 100 x _________________________
CT1(T2 - 25) - CT2(T1 - 25)
TC
= Temperature coefficient
CT1 =Conductivity at Temp. 1
CT2 = Conductivity at Temp. 2
T1 = Temp. 1
T2 = Temp. 2
25
= 25°C
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, Enter Advanced set-up mode. Push the ENTER key.
Press the
▲
key to scroll to security code “22”. Push the ENTER key again.
B. Press the
▲
and
▼
keys to scroll until the upper display shows tc.
C. Press the ENTER key until the lower display shows P.tc and the upper display
shows the temperature coefficient.
D. Press the
▼
key until the upper display shows 0.0.
E. Press ENTER key to confirm the value.
F. Press the
▲
and
▼
keys together to return to measurement mode.
2.
Wait for 5 minutes. Note T1 and CT1 (conductivity at T1).
3.
Condition the sample solution and probe to a temperature (T2) that is about 5°C
to 10°C different from T1, and note the conductivity reading CT2.
NOTE:
Record your results for future reference. Ideally T1 and T2 should bracket
your measurement temperature, and should not differ 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, Enter Advanced set-up mode. Push the ENTER key.
Press the
▲
key to scroll to security code “22”. Push the ENTER key again.
B. Press the
▲
and
▼
keys to scroll until the upper display shows tc.
C. Press the ENTER key until the lower display shows P.tc and the upper display
shows the temperature coefficient.
D. Press the
▲
key until the upper display shows your calculated temperature
coefficient.
E. Press ENTER key to confirm the value.
F. Press the
▲
and
▼
keys together to return to measurement mode.
The calculated temperature coefficient will now be applied to all the meter readings.
14. Appendix 3: Jumper positions
Note that there is a fuse internal to the controller. Before opening the unit, ENSURE
that the power cable is physically separated from the mains supply. Replace the
fuse with the recommended part specified by the manufacturer.
Jumper Positions - Internal to the controller
JP 1
Selects the input voltage 220 VAC. To switch to 110 VAC, use tweezers or
needle nose pliers to remove jumper from JP1 pins to JP2 pins.
JP 2
Selects the input voltage 110 VAC. To switch to 220 VAC, use tweezers or
needle nose pliers to remove jumper from JP2 pins to JP1 pins.
Pt 100/ Selects between Pt100 and Pt1000. To switch between Pt 100 and Pt 1000,
Pt 1000 de-solder and remove jumper from left-center position, move and re-solder
to right center position.
View from the top
Rear
FUSE
JP1
Front
220 VAC
110 VAC
JP2
Pt100 Pt1000
