VEGA MINITRAC 31 4 … 20 mA_HART - four-wire - Manual (Page 32)

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6 Set up with the display and adjustment module
MINITRAC 31 • 4 … 20 mA/HART - four-wire
40447-EN-131119
Select "Determine count rate" to enter the first point.
The determination of the actual count rate lasts 2 minutes. After the
count rate has been determined, you can accept the value (ct/s).
Enter now the corresponding level (m).
By doing so, you assign a respective level to the actual count rate.
Accept the value pair with "OK".
Depending if you have started with full or empty vessel, you have to
continue emptying or filling the vessel.
Also carry out such a linearization with several different filling heights
if you have a linear vessel.
A maximum of 32 linearisation points is possible.
In this menu item you can adjust the damping of the sensor. With
it you can suppress fluctuations in the measured value indication,
caused e.g. by an agitated product surface. This time can be between
1 and 1200 seconds. Keep in mind that the reaction time also in-
creases and the instrument reacts to quick level changes with a delay.
Generally a time of approximately 60 seconds is sufficient to smooth
the measured value indication.
Radiation from external sources can influence the measuring result of
the sensor.
Possible external radiation sources can be, for example, a weld joint
test on a neighbouring facility or other radiation-based instruments.
An X-ray alarm is triggered if the impulses (ct/s) are more than 25 %
above the max. value from the linearization table.
This fault message is only outputted for the period of the increased
X-ray radiation. Then the fault message is automatically reset.
In this menu item you can determine the behaviour of the sensor
when external radiation sources appear.
In this menu item you can activate the relay output and determine its
function as well as the switching points.
When the output of the process values is set, you can choose be-
tween overfill and dry run protection.
The relay outputs of the sensor react accordingly.
You can choose "no" reference value. In this case, the relay output
operates as fail safe relay.
Caution:
Independent of the selected reference value, the relay will deenergize
in case of failure.
Setup - Damping
Setup - External radiation
alarm
Setup - Relay