46
8026957/AE00/V1-0/2021-08| SICK
O P E R A T I N G I N S T R U C T I O N S | DUSTHUNTER SB30
Subject to change without notice
4
START-UP AND PARAMETER SETTINGS
4.2.10
Calibration for dust concentration measurement
For exact dust concentration measurement, the relation between the primary measured
variable scattered light intensity and the actual dust concentration in the duct must be
established. To do this, the dust concentration must be determined based through a
gravimetric comparison measurement according to DIN EN 13284-1 and set in relation to
the 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”.
▸
Enter Level 1 password (
see “Password for SOPAS ET menus”, page 40
▸
Estimate the measuring range required for the dust concentration in operational state
and enter the upper and lower end values.
▸
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
“Scattered light intensity” 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
SI:
Measured scattered light intensity
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.
NOTE:
Carrying out a gravimetric comparison measurement demands special knowledge that
cannot be described in detail here.
c
K2 I
out
2
K1 I
out
K0
+
+
=
(1)
I
out
LZ SL
20mA LZ
–
MBE
-----------------------------
+
=
(2)
NOTE:
In this case, the regression coefficients set in the sender/receiver unit and the
measuring range set in the MCU (option) may not be changed anymore. On the
LC-Display of the MCU (option), the dust concentration is shown in mg/m³ as
uncalibrated value.