First Time Operation; Operational Functions; Dcc Function - Michell Instruments Optidew User Manual

Optidew User's Manual
protection from liquid droplets and can even stop flow to the analyser completely when a
large slug of liquid is encountered, saving the sensor from potentially irreparable damage.

4.3.2. First Time Operation

Before using the instrument, please read through the Installation, Operation and Maintenance
sections of this manual. This instruction assumes that all recommendations within these
sections have been followed, and that the control unit and sensors are physically installed
and all electrical connections complete.
• Ensure that all sample connections are in good condition, of appropriate materials and are
leak-tight
• Clean the mirror according to the instructions in section 6.1
• Control the flow rate to within 0.1 to 2Nl/min (1l/min optimal)
• Power on the instrument
NOTE: if the dew point sensor has been swapped, refer to section 5.2

4.4. Operational Functions

4.4.1. DCC Function

Dynamic Contamination Control (DCC) is a system designed to compensate for the loss of
measurement accuracy which results from mirror surface contamination.
During the DCC process the mirror is heated to a default temperature of 20°C above the dew
point to remove the condensation which has formed during measurement.
The surface finish of this mirror, with the contamination which remains, is used by the optics as
a reference point for further measurements. This removes the effect of contamination on
accuracy.
After switch-on, the mirror is assumed to be clean, therefore the instrument will only run a
DCC for 2 minutes to quickly establish a clean mirror reference point. By default, every
subsequent DCC is 4 minutes in duration and will automatically occur every 4 hours.
At certain times it may be desirable to disable the DCC function in order to prevent it from
interrupting a measurement cycle, e.g. during a calibration run. This is achieved by setting 'Mode'
to 'Manual' in the DCC menu. See section 3.2 for further details.
A manual DCC can be initiated or cancelled by touching the DCC button on the Main Screen. The
DCC button is context sensitive, i.e. if DCC is on, the Main Screen shows DCC OFF as being
selectable. Similarly, if DCC is off, DCC ON is shown.
It is possible to change the parameters relating to the DCC cycle on the DCC Setup Screen, refer
to Section 3.2.
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