Mirror Cleaning; Figure 31 Mirror Contamination Warning - Michell Instruments Optidew User Manual

Optidew User's Manual
5 MAINTENANCE
5.1

Mirror Cleaning

Throughout the life of the instrument, periodic cleaning of the mirror surface and optics
window may be required. The frequency of this depends upon operating conditions and
the potential in the application for contaminants to be deposited on the mirror.
The Optidew will notify the user on the state of mirror contamination. The instrument will
initially give a warning in the sensor status display (or as a Magenta/flashing Magenta
indication on the transmitter version) when contamination is detected, but will continue
to operate. Cleaning the mirror, then running a DCC is necessary when this warning is
displayed.
If the contamination reaches levels which will drastically affect performance, a fault
alarm will trip, causing the instrument to switch to standby mode until action is taken.
For remote indication of an optics warning, the process alarm contact can be set to trip
whenever the optics warning is active. See sections 3.2 and 4.6 for further information.
The cleaning procedure is as follows:
1. Set the instrument to Standby
2. If mounted in a sample block, disconnect the sensor cable and remove
the sensor from the block.
3. Clean the mirror surface and optics window fi rstly with a cotton bud/Q-
Tip soaked in distilled water, then with one of the following solvents:
methanol, ethanol, or isopropyl alcohol. To avoid damage to the mirror
surface do not press too fi rmly on the cotton bud/Q-Tip when cleaning.
Allow the cleaning solvent to fully evaporate.
4. Press the 'Calibrate Optics' button in the 'Alarms' screen
Michell Instruments
Mirror contamination warning
Figure 31
MAINTENANCE
41