13
3.3 Dissolved Oxygen Calibration Notes
1.
The relationship of % Saturation and ppM depends on a number of variables, so
always
calibrate in the mode required
. Do not try to infer Oxygen content from one mode to another.
2.
A zero calibration should be performed at least monthly. In applications where there is a low
level of dissolved oxygen, a zero calibration may have to be done weekly.
3.
An air calibration should be performed at least weekly. Of course, more frequent calibration
will result in greater confidence in results.
4.
All calibration information is retained in memory when the
90-FLMV
is switched off. This
information can be recalled or printed later using the GLP function (see section 10).
3.4 Dissolved Oxygen Calibration Messages
1.
If a Zero calibration has been successfully performed, the
90-FLMV
will display the following
message and the Zero value of the sensor…
0.0%Sat 25.0
o
c
Calibration OK, Zero=0.5%
2.
If a Zero calibration has failed, the
90-FLMV
will display the following message and the failed
Zero value of the sensor. The unit will return to normal display mode with a “
∗∗∗∗
” in place of
the decimal point in the Dissolved Oxygen reading.
15.0%Sat 25.0
o
c
Calibration Failed, Zero=15.0%
3.
If an Air/Span calibration has been successfully performed, the
90-FLMV
will display the
following message and the Span value of the sensor…
100.0%Sat 25.0
o
c
Calibration OK, Span=100.0%
4.
If an Air/Span calibration has failed, the
90-FLMV
will display the following message and the
failed Span value of the sensor. The decimal point will be replaced by a “
∗∗∗∗
” when the unit
returns to normal display mode.
205.0%Sat 25.0
o
c
Calibration Failed, Span=205.0%
5.
The allowable Span range for a Dissolved Oxygen sensor is 65.0 to 200.0 %. If calibration fails
due to the Span value being outside these limits, then please consult the Troubleshooting guide
(section 18.2) for possible remedies.
