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DUSTHUNTER T · Operating Instructions · 8012428 V2.2 · © SICK AG
Start-up and Parameter Settings
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4.4.7
Calibrating for dust concentration measurement
For exact dust concentration measurement, the relation between the primary measured
variable transmission and the resulting calculated measured variable extinction and the
actual dust concentration in the duct must be established. To do this, the dust
concentration must be determined based on a gravimetric measurement according to DIN
EN 13284-1 and set in relation to the extinction values measured at the same time by the
measuring system.
Steps to be carried out
Select device file "MCU", set the measuring system to "Maintenance" mode and enter
the Level 1 password (
).
Select the "Configuration / IO Configuration / Output Parameters DUSTHUNTER" direc-
tory (
) and assign the "Extinction" measured variable to an analog output.
Estimate the measuring range required for the dust concentration in operational state
and enter this in the "Analog Output 1
(2/3)
Scaling" field assigned to the selected ana-
log output for output of the extinction.
Deactivate "Maintenance" mode.
Carry out the gravimetric comparison measurement according to DIN EN 13284-1.
Determine regression coefficients from the mA values of the analog output for "Extinc-
tion" and the actual dust concentrations measured gravimetrically.
c:
Dust concentration in mg/m³
K2, K1, K0:
Regression coefficients of the function c = f (I
out
)
I
out
:
Current output value in mA
Ext: Measured
extinction
LZ:
Live Zero
MBE:
Defined upper range limit value (value entered for 20 mA;
normally 2.5 x fixed limit value)
Enter the regression coefficients
There are two options:
– Direct input of K2, K1, K0 in a measured value computer.
NOTICE:
The steps described here serve to avoid input errors. Carrying out comparison
measurements demands special knowledge that cannot be described in detail
here.
NOTICE:
In this case, the regression coefficients set in the sender/receiver unit
and the measuring range set in the MCU may not be changed anymore.
On the optional LC Display (when used), the dust concentration is
displayed as uncalibrated value in mg/m³.
c
K2 I
out
2
K1 I
out
K0
+
+
=
(1)
I
out
LZ Ext
20mA LZ
–
MBE
-----------------------------
+
=
(2)