envea STACK 602, Руководство пользователя

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STACK 602 9 Maintenance
ENVEA UK Ltd
(PC-000848-MA Issue 5, December 2021)
vii
8.3 Dynamic Opacity (Dust) Self-Tests
8.3.1 About DynamicOpacity
®
Self-Tests
The numerical values displayed on the ‘Dust’ (Dynamic Opacity) QA/Self Tests
page (see
Figure 23
below) are all measures of raw scintillation counts. Raw
scintillation is the amount of light signal variation seen at the Receiver due to the
dust flow.
Dynamic Opacity is calculated as follows:
Dynamic opacity = scintillation (SC diagnostic channel) / received
intensity (I diagnostic channel) x 100,000
Example: if
SC=200
and
I=800,000
, then
Dynamic Opacity = 200/800,000 x 100,000 = 25.
8.3.2 Viewing Dynamic Opacity Self-Tests
1. Open the QA/Self-Tests menu screen, then select Device | Stack n Dust
to display the self-test results for a sensor (
Figure 23
).
Figure 23: Dynamic Opacity sensor test results (alternating).
1a. Light Normal : displays the current level of scintillation at the Receiver.
This should be the same as the light level set up initially on the Set-Up
screen. A typical value is between 10 and 1,000 (see section
0
on page
42
).
1b. Comms Check : verifies the control unit is reading dynamic opacity
values correctly from the sensor.
1c. Dynamic Opacity Light Off (ZERO) check : this check turns the
Transmitter brightness down to zero and checks the scintillation also
drops close to zero.
Example: referring to
Figure 23
above, the result shows a Light Normal
scintillation count of 463 just before the test which is reduced to 9 during
the test.
1d. Dynamic Opacity Light 50% (SPAN) check : the aim of this test is to
simulate a dynamic opacity reading electronically by oscillating the
Transmitter brightness between 100% and 50% (its original setup level)