CODEL
OPS. 141
25
Issue : A
Revision : 1
Date : 14/06/18
Doc i/d :
0118/6
050028
4. Operation
4.1. Introduction
After the instrument has been commissioned, it will measure the transmissivity
between the transmitter and receiver, and produce an output proportional to
either the opacity, dust, Ringelmann or extinction level. An integral 32-character
display also shows the calculated levels.
The instrument allows the operator to interrogate the micro-processor to
observe the system parameters, and to change them if required.
A menu based program is used and access is gained by four keys mounted on
the lid of the signal processor.
4.1.1. Measurement
To calculate the opacity, an LED light source is positioned on side of the duct,
and a detector at the other. The light from the LED is modulated (to avoid
interference from ambient light) and the level from the detector is a measure of
the opacity in the duct. In addition, a detector within the transmitter constantly
monitors the intensity
to provide a reference.
4.1.2. Calibration
During the commissioning procedure a calibration is conducted, which sets the
system gain to produce a zero or known opacity. An automatic zero facility
allows the instrument to compensate for a slow build-up
of optical contamination.
4.2. Operating Modes
The instrument has six modes of operation which are identified by a number in
the top left-hand corner of the display :
1.
Operating Mode
- display average opacity, extinction, dust
density or Ringelmann level.
2.
Parameter Mode
- display operating parameters.
3.
Normalisation Data
- display normalisation data.
4.
Diagnostic Mode
- investigate instrument operation.
