VEGA FIBERTRAC 31 4 … 20 mA_HART - four-wire With SIL qualification - Manual (Page 53)

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7 Set up with the display and adjustment module
FIBERTRAC 31 • 4 … 20 mA/HART - four-wire
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the adjustment of the sensor with full status (covered) and with empty
status (uncovered).
Hence, you will get a very reliable switching point.
With single point adjustment, you have to define the difference
between the min. and max. adjustment points (Delta I) yourself during
the following setup.
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 FIBERTRAC
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 FIBERTRAC 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
FIBERTRAC 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.
Setup/Adjustment
uncovered (single point
adjustment)
Setup/Delta I (single
point adjustment)