Vega POINTRAC 31 - 3.2 Principle of operation; 3.3 System limitations

9
3 Product description
POINTRAC 31 • 8/16 mA/HART - four-wire
43388-EN-180322
This operating instructions manual applies to the following instrument
versions:
•
Hardware from 1.0.6
•
Software from 2.0.0
Theinstrumentisavailableindierentelectronicsversions.Eachver-
sioncanbeidentiedviatheproductcodeonthetypelabel:
•
StandardelectronicstypePROTRACH.-XX
The scope of delivery encompasses:
•
Radiation-based sensor
•
Mounting accessories
•
Documentation
•
Bluetooth module (optional)
– This operating instructions manual
– Safety Manual (SIL)
– Ex-specic"Safety instructions" (with Ex versions)
– Ifnecessary,furthercerticates
3.2 Principle of operation
The instrument is suitable for applications in liquids and bulk solids in
vesselsunderdicultprocessconditions.Thereareapplicationpos-
sibilities in nearly all areas of industry.
The limit level is detected contactlessly through the vessel wall. Nei-
theraprocessttingnoravesselopeningisrequired.Theinstrument
isthusidealforretrotting.
In radiation-based measurement, a Caesium-137 or Cobalt-60 iso-
tope emits focussed gamma rays that are attenuated when penetrat-
ing the vessel wall and the medium. The PVT detector on the opposite
side of the tank receives the radiation. When the intensity of the
radiationdropsbelowadenedvalue,e.g.duetodamping,thenthe
POINTRAC 31 switches. The measuring principle has proven itself
well under extreme conditions because it measures contactlessly
from outside through the vessel wall. The measuring system ensures
maximum safety, reliability and plant availability independent of the
medium and its properties.
3.3 System limitations
Thereareseveralmeasuringprinciple-specicfactorswhichcaninu-
ence the measuring result. Keep these factors in mind in order to fully
utilize the capabilities of the instrument with respect to measurement
reliability and reproducibility.
The implemented radioactive isotope and its activity must be selected
according to the properties of the vessel and the medium. The neces-
sary radioactive activity must be calculated on the basis of the plant
data.
Scope of this operating
instructions manual
Electronics versions
Scope of deliv
ery
Application area
Functional principle
Activity of the source