VEGA POINTRAC 31 Foundation Fieldbus - Manual (Page 25)

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6 Set up with the display and adjustment module
POINTRAC 31 • Foundation Fieldbus
41779-EN-131119
This menu item appears only if you have selected "Single point
adjustment" as adjustment mode (Setup/Adjustment mode).
In this menu item you determine the point at which the POINTRAC 31
should switch in uncovered status.
Empty the vessel until the sensor is uncovered.
For this enter the requested pulse rate manually or let the rate be
determined by POINTRAC 31. Automatic determination of the pulse
rate should be given preference.
The pulse rate is entered in ct/s. This is the number of counts per
second, i.e. the measured gamma radiation reaching the sensor.
Prerequisites:
•
Radiation is switched on - Source container is set to "ON"
•
There is no medium between source container and sensor
You can enter the value for "Adjustment uncovered" (ct/s) manually.
You can have the value for "Adjustment uncovered" determined by
POINTRAC 31.
This menu item appears only if you have selected "Single point
adjustment" as adjustment mode (Setup/Adjustment mode).
In this menu item you can adjust at which percentage value of the
max. pulse rate the sensor should switch over.
Since in most cases the radiation is almost completely absorbed
when the sensor is covered, the pulse rate when the sensor is cov-
ered is very low.
The change between the two statuses is sufficiently clear.
Hence a percentage value of 90 % for the Delta I value is recom-
mended.
You select lower values for sensitive detection of material cones or
buildup which cause only partial absorption of the radiation.
Setup - Adjustment
uncovered (single point
adjustment)
Setup - Delta I (single
point adjustment)