VEGA MINITRAC 31 4 … 20 mA_HART - four-wire - Manual (Page 9)

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3 Product description
MINITRAC 31 • 4 … 20 mA/HART - four-wire
40447-EN-131119
1 2
3
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Fig. 2: MINITRAC 31 - Application possibilities
1 Level measurement - Residue detection
2 Point level detection
3 Density measurement
4 Mass flow measurement
Further application possibilities are also the use as X-ray alarm or real
value correction.
If X-ray alarm is selected, the instrument detects radiation from exter-
nal sources. Possible external radiation sources can be, for example,
a weld joint test in a neighbouring facility or other radiation-based
instruments.
When the instrument operates as real value correction it transmits the
real value to correct another radiation-based sensor. The measure-
ment can thus be adapted perfectly to the situation in the vessel.
In radiation-based measurement, a Caesium-137 or Cobalt-60 iso-
tope emits focussed gamma rays that are attenuated when penetrat-
ing the tube wall and the medium. The NaI detector on the opposite
side, on a pipeline for example, receives the radiation. The intensity
of the radiation is dependent on the density of the measured media.
The measuring principle has proven to be very reliable in conjunction
with extreme process conditions because it measures contactlessly
Functional principle