General Information
Read this section before proceeding with
Sections 2,3,4,5 and 6
Before calibrating, or making a measurement on any mode, it is
important to note the
+
The cell constant is correct
•
The temperature coefficient is correct
+
Any unnecessary calibration data is cleared.
+
Calibration data is indicated by the presence of the word
CAL on the display. To inspect the data, press the Chk key.
Calibration points are shown in sequence. To clear the data,
remain in CHK mode and press and hold down the Enter
key for 5 seconds.
+
The cell constant is not considered to be calibration data
but a physical constant. The value
will not
be erased by the
Clear procedure.
+
The temperature coefficient
will
be eased by the clear proce
dure so always make a note of it and re-enter if necessary.
+
All measurements are automatically temperature compen
sated to a base temperature of25
°
C.
+
To make un-compensated measurements then the tempera
ture coefficient should be set to zero.
9
Section 2
Conductivity
Please refer to page 9 before proceeding.
The following can only be carried out if the instrument has not
been calibrated in Concentration Mode.
Most conductivity cells are linear over a wide range. Since the cell
constant has already been set (see p 7), measure conductivity as
follows:
0
Connect cell and select conductivity mode
El
Place cell in sample
0
Wait for a stable reading and record result noting the units.
For very accurate results any non-linearity arising from polarisation
effects, may be calibrated out as follows:
0
Prepare up to four calibration solutions, each with a known
conductivity
El
Connect cell and select conductivity mode
0
Place cell in first standard and wait for a stable reading.
Using the jJ, is keys, adjust the reading to the correct value
(CAL flag will flash). Press Enter. (CAL flag will stop
flashing).
0
Repeat 0 for each standard.
0
Place cell in sample and record value noting units.
The calibration points may be inspected at any time as follows:
CD
@
@
©
Press Clear
First a number identifier is displayed and then the standard
value.
This is repeated for each standard.
Return to the function you require by pressing the Mode
key.
10
