Measuring Principle - Endress+Hauser PROFIBUS Gammapilot M FMG60 Operating Instructions Manual

Appendix
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11.4

Measuring principle

The radiometric measuring principle is based on the fact that gamma radiation is attenuated when
it penetrates a material. Radiometric measurement can be applied for different measuring tasks:
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11.4.1 Level limit detection (1)
A gamma radiation source and a Gammapilot M are mounted on opposite sides of the vessel at the
height of the desired level limit. The Gammapilot M converts the received radiation intensity into
a percentage. "0%" means that the radiation path is completely free, i.e. the level is below the limit.
"100%" means that the radiation path is completely covered, i.e. the level is above the limit.
11.4.2 Continuous level measurement (2)
A gamma radiation source and a Gammapilot M are mounted on opposite sides of the vessel. The
Gammapilot M calculates the level (percentage) from the radiation intensity. For adaption to the
measuring range detectors of different lenghts are available. Also, multiple detectors can be
interconnected (cascading).
11.4.3 Measurement of interface layers (3)
A gamma radiation source and a Gammapilot M are mounted on opposite sides of the vessel in a
height such that both liquids are irradiated. The radiation source may also be mounted inside the
vessel. The Gammapilot M calculates the position of the interface layer from the intensity of the
received radiation. Its value is between 0% (lowest possible position) and 100% (highest possible
position).
11.4.4 Density or concentration measurement (4)
A gamma radiation source and a Gammapilot M are mounted on opposite sides of a measuring tube.
The Gammapilot M calculates the density or concentration of the medium from the intensity of the
received radiation. The unit can be freely selected.
If an additional temperature sensor (5) is connected, the Gammapilot M accounts for the thermal
expansion of the medium. That means, it does not output the measured density directly. Instead it
calculates the density which the medium would have at a certain standard temperature defined by
the user.
Gammapilot M
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Gammapilot M
Gammapilot M
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Gammapilot M FMG 60 - PROFIBUS PA
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Gammapilot M
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