Maintenance; Calibration; Sensor / Battery Replacement - Michell Instruments Easidew Portable HP User Manual

MAINTENANCE

5 MAINTENANCE
Routine maintenance of the Easidew Portable is confined to regular re-calibration of the
internal, removable Easidew sensor and replacement of the filter cartridge.
5.1

Calibration

The calibration of the internal sensor is traceable to national standards. For this reason
it should only be calibrated in an accredited, e.g. UK United Kingdom Accreditation
Service (UKAS) or US National Institute of Standards and Technology (NIST) standards
laboratory. If these facilities do not exist it is recommended that the sensor is returned
to the manufacturer, Michell Instruments, or an approved agent. A calibration certificate
bearing a seven-point calibration is issued with each sensor.
In most applications, annual re-calibration ensures that the stated accuracy of the
Easidew sensor is maintained.
5.2

Sensor / Battery Replacement

To remove the sensor, or battery pack:
1. Ensure instrument is switched off and that the battery charger, current
output and any sampling components are also disconnected.
2. Remove and retain the 10 cross-head screws from the top plate.
3. Lift the small battery pack cover in the top right corner of the instrument.
A small flat bladed screwdriver may be required to gently pry the edges
of the cover if it has become stuck to the waterproof seal underneath.
Removing this cover first will make it easier to lift the entire top panel out
of the instrument.
4. Lift the top plate of the instrument out of the case. Disconnect the battery
pack before removing the top plate completely to prevent it from straining
on the attached cable. If only replacing the battery pack, do not follow
the next two steps.
5. Undo the screw from the centre of the sensor connecting plug and pull
off the connector.
6. Unscrew the sensor from the block.
Fitting the replacement is simply a reversal of the above procedure. When fitting a new
sensor it may be necessary to change the alignment of the GDSN connector (see next
page).
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Easidew Portable HP User's Manual
97120 Issue 2.3, October 2019