Maintenance; Mirror Cleaning; Figure 32 Sensor Cleaning - Michell Instruments Optidew User Manual

Optidew User's Manual

6. MAINTENANCE

6.1. 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 5 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 firstly 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 firmly 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. For the Optidew 501 Transmitter
without display refer to Section 3.3.1, Optics Calibration

Figure 32 Sensor Cleaning

44
WARNING: Do not attempt to remove the
sensor potting from the mirror during cleaning
(as shown in Figure 27 right hand side picture)
97551 Issue 4.1, October 2019