D-FL 200 / Rev. 6
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Industrie Elektronik GmbH & Co KG
6. Measuring Sequence
6.1. Self-Check
The evaluation unit performs a self-check upon power-up. The display will indicate “Self-Check”
throughout the duration of the test and the relay contact "Maintenance“ is in operation.
6.2. Calibration Cycle
After the self-check a calibration cycle is performed for 4 minutes. The calibration
cycle consists of a ‘zero test’ and ‘span test’. This cycle is performed according to the
time interval programmed in program mode2 (standard every 24h). The state output
contact “Maintenance” is contacted during this period.
Unaffected of this two calibration tests an automatic check cycle is performed. This
automatic check cycle inspects the right operation of the electronic parts. It takes
place beside the permanent measuring cycle.
6.2.1. Zero Test
After the sensor check, a zero test is performed for two minutes. Each sensor
transmits two brief impulses, which are received by the opposite sensor. This
sequence is repeated in both directions. The zero point is checked using the
evaluation formulas noted above.
6.2.2. Span Test
During the span test, staggered signals are transmitted and received. Using the
evaluation formulas, the reference point can be checked.
6.3. Monitoring
The system automatically begins monitoring after the calibration cycle. The state
output contact “Maintenance” changes from the position “ON” to “OFF”.
7. Registration of Measured Values
The D-FL 200-10 is equipped with two mA outputs. The standard volumetric flow is given to output 1,
and the gas velocity is given to output 2.
For continuous registration of measured values, strip chart recorders (0-20 mA) with a printing width of
at least 100 mm (4 inch) can be used (quality class 1.0, according to VDE 0410. The zero point (live
zero) lies at 20% (4 mA) of scale.
A computerized emissions evaluator may also process the measured values issued.
The integration time (continuous mean value generation) of the measured value can be set in the D-FL
200-10 in one-second steps between 1 and 180 seconds.
