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8012428/YWL2/3-0/2016-08| SICKO P E R A T I N G I N S T R U C T I O N S | DUSTHUNTER T
Subject to change without notice
2 PRODUCT DESCRIPTION
Zero value measurement
The sender diode is switched off for zero point control so that no signal is received. This
means possible drifts or zero point deviations are detected reliably in the overall system
(e.g., due to an electronic defect). A warning signal is generated when the “zero value” is
outside the specified range.
Control value measurement (Span test)
Sender beam intensity changes between 70 and 100% during control value determination.
The light intensity received is compared against the standard value (70%). The measuring
system generates an error signal for deviations greater than ±2%. The error message is
cleared again when the next function check runs successfully. The control value is deter-
mined with high precision through statistical evaluation of a high number of intensity
changes.
Contamination measurement (not on DUSTHUNTER T50)
The glass panes positioned in the sender beam during normal measurement are swiveled
away during contamination determination. The measured value determined and the value
defined during scaling are used to calculate a correction factor see “Scaling the measuring
system for transmission measurement”, page 67. This fully compensates any contami-
nation that occurs.
Contamination is determined on one side on the DUSTHUNTER T100 (pivoted shutter only
on the sender/receiver unit) and on both sides on the DUSTHUNTER T200 (pivoted shutter
also on the reflector).
Fig. 4: Contamination measurement principle (on both sides)
An analog value between live zero and 20 mA proportional to contamination is output
during the check cycle for contamination values < 30%, (DUSTHUNTER T100) or 40%
(DUSTHUNTER T200); when this value is exceeded, the “Failure” status is output (for the
fault current set on the analog output for this case; see “Factory settings”, page 74, see
“Setting the analog outputs parameters”, page 76).
Sender/receiver unit
Reflector
Pivoted shutter
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