Optional Optical Probes Calibration And Maintenance - palintest Macro 900 Operation Manual

Macro 900 Operation Manual V3

15. Optional Optical Probes Calibration and Maintenance

The MAP 2000/2100 is constructed with an aluminium sleeve surrounding the
delicate sensing probes. The Sleeve can be easily removed by unscrewing to
allow cleaning of the individual electrodes, however, the Probe sleeve forms
an integral, working part of the Probe's measurement system, and
MUST be fitted for correct operation.
All Palintest Optical Probes are incredibly sensitive. For example, the Turbidity
electrode is capable of measuring between 0 and 3000NTU with an internal
resolution of greater than 0.1NTU. This means that the electrode is able to
detect changes in turbidity that are less than 0.003% of the full range! The
other Optical Probes have a similar level of sensitivity.
It follows, therefore, that in order to provide stable, repeatable readings, the
environment in which the measurements are made must be completely stable
and repeatable.
For this reason, the MAP
2000/2100 is constructed
with a matt black aluminium
sleeve and end cap that
enclose the sensing
electrodes and provide a
closed, constant condition,
non-reflective measurement
chamber.
This is essential for the
correct calibration and
operation of all types of
Optical Probes.
A diagram of the MAP
2000/2100's measurement
chamber is shown here.
In order to obtain consistent results, the measurement chamber
created within the Macro Accessory Probe must remain physically
constant during both calibration and measurement.
If the optical electrode is calibrated under one set of conditions then used to
measure under another set of conditions, the readings will naturally be
erroneous, especially at low concentrations.
A perfect example of this is calibrating with the end cap removed then
measuring with the end cap fitted (or vice-versa). By changing the physical
characteristics of the measurement chamber, you also change the calibration
and response of the electrode.
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