Principle Of Operation; Measuring Principle; Adjustment; Displays And Alarms - Deckma Hamburg OMD-2008 Instruction Manual

3 Principle of operation

3.1 Measuring Principle

An optical sensor array measures a combination of light scattered and absorbed
by oil droplets in the sample stream. The sensor signals are processed by a
microprocessor to produce linearized output.
If an alarm (works set point 15 ppm, or 10 ppm or 5 ppm respectively) occurs, the
two oil alarm relays are activated after the adjusted time delay.
The microprocessor continuously monitors the condition of the sensor
components and associated electronics to ensure that calibration accuracy is
maintained over time and extremes of environmental conditions.

3.2 Adjustment

The unit is delivered with a works calibration according the IMO-requirements.
The alarm points are set to 15 ppm (or 10 ppm, or 5 ppm for certain versions).
The "Zero" point is also works calibrated and can be re-adjusted on site by using
the programming mode and clean water. See Section 10.4 "Settings-Offset".
Calibration of the instrument is not permitted. According to IMO Regulations a
calibration check has to be done by the manufacturer or persons authorized by
the manufacturer. The recommended way to ensure a properly calibrated
Measuring Cell on board is to exchange the Measuring Cell.

3.3 Displays and Alarms

In the unit there are two independent oil alarm circuits available. Both can be set
separately from 1 to 15 ppm. From the manufacturing both alarms are set to
15 ppm (according IMO). The set points can be changed according to the
requirements on site, for example to 10 ppm or 5 ppm. An alarm point setting
above 15 ppm is not possible. Instrument versions with limited alarm setpoint
range (10ppm, or 5ppm) are available. This alarm setpoint limit can not be
changed.
Adjustment of the alarm setpoints can be done in the programming mode as
described in Section 10.4. In this mode also the individual adjustment of the time
delays for the alarms can be done.
Both alarm circuits are also related to an alarm LED on the front panel.
Issue: 25.09.2015 preliminaryInstruction Manual OMD-2008 (All Versions)
DECKMA HAMBURG GmbH
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