Cell Check
For Instruments with Software Version
2.10 & Later.
In these versions, a
Cell Check
feature has been added to further
increase the performance of your instrument. This is especially important
when in
R E S
mode reading High Resistivity or Ultrapure waters. This
feature, utilizing technological improvements, knows when the
Conductivity Cell cup is dirty and calls it to your attention. You may then
choose to clean the Conductivity Cell cup or ignore it by pressing the
CAL key. Follow the steps below to perform a
Cell Check
.
1.
Press
key to power up the unit.
2.
Verify that the cell cup is empty
of any solution and "
- - - -
" is
displayed by the Ultrameter. If
a reading other than "
- - - -
" is
displayed, clean the cell cup
and repeat steps 1 & 2. See
"Cleaning Sensors".
3.
Press the
key until
"
CELL ch
" appears. Fig. 2.
4.
Press the
key. If the cell
is clean, “
Good
” will
momentarily be displayed. Fig. 3.
5.
If the
Cell Check
has failed
the display will show
“
C E L L
cLn
”, Fig. 4, alternating
with a number such as “
5 3
”,
Fig. 5, indicating a relative
amount of contamination or dirt
in the Conductivity Cell. To
insure the highest quality
readings, the Conductivity Cell
cup should be cleaned before
measuring High Resistivity
solutions. Rinse the cup with
DI water several times to clean,
and Shake instrument well to
remove excess water.
Repeat steps 1-4.
2
Figure 2
Figure 4
Figure 5
Figure 3
CAL
MCLR
MR
R E S
I.
ENHANCED HIGH RESISTIVITY MEASUREMENTS
The resistivity calculations in the Ultrameter have been improved for
measuring waters greater than 10 Megohms. When the Ultrameter is in
one of the solution modes (i.e. KCl, NaCl or 442) and the resistivity
reading is greater than 10 Megohms, the Ultrameter performs automatic
temperature compensation for high purity water. As such, the maximum
possible value that should be displayed for water is 18.2. It may be
possible to display readings higher than 18.2 if the instrument is not
calibrated or if solutions
other than water
are being measured. To
insure proper use of the instrument in this mode, readings greater than
20 Megohms will display "
- - - -
" indicating an over-range condition. To
obtain resistivity readings for solutions
other than water
, the User
mode should be selected. In User mode the Ultrameter will display
resistivity measurements up to 30 Megohms.
An
Offset Zero Calibration
feature was added to software version
2.03, and must be performed by the user, see below. On all later versions
this function is performed at time of manufacture.
A
Cell Check
feature was added to these later versions. See page 2.
Offset Zero Calibration
For Instruments with Software Version
2 . 0 3
When performing measurements of waters above 10 Megohms, the
accuracy of the Ultrameter may be improved by performing an offset zero
calibration. Follow the steps below to perform an offset zero calibration.
1.
Press
key to power up the unit.
2.
Verify that the cell cup is empty of any solution and "
- - - -
" is
displayed by the Ultrameter. If a reading other than "
- - - -
" is
displayed, clean the cell cup and repeat steps 1 & 2. See
"Cleaning Sensors".
3.
Press the
key until
"
C A L 0
" appears. Fig. 1.
4.
Press the
key. The
instrument should momentarily
display a number of counts, and return to Resistivity mode.
5.
If the calibration has failed the display will show "
Err
". If an error
occurs during this step, the cell cup is probably contaminated.
Rinse the cup with DI water several times to clean and Repeat
steps 1-4.
R E S
CAL
MCLR
MR
Figure 1
1
