VEGA VEGAFLEX 81 Modbus and Levelmaster protocol Coax probe - Manual (Page 50)

50
7 Setting up sensor and Modbus interface with PACTware
VEGAFLEX 81 • Modbus and Levelmaster protocol
42283-EN-130314
Interface measurement: If you select "Interface", the instrument needs
more information, such as the distance to the interface, the dielectric
constant of the upper medium or whether or not there is a superim-
posed gas phase.
Demonstration mode: This mode is suitable for test and demonstra-
tion purposes. In this mode, the sensor ignores all logic parameters
and reacts immediately to all measured value changes within the
measuring range.
Application - Level measurement
The level measurement refers to the product surface which is the limit
to the gas phase.
•
Liquids
– Solvents, oils, LPG - dielectric constant < 3
– Chemical mixtures - dielectric constant 3 … 10
– Water-based - dielectric constant > 10
•
Bulk solids
– Dusts, wood chips - dielectric constant < 1.5
– Granules, dusts, powders - dielectric constant 1.5 … 3
– Cereals, flour - dielectric constant > 3
Application - Interface measurement
The interface measurement refers to the phase limit between two
liquids. The total level is also available as a measured value.
•
Superimposed gas phase present
– Check if there is a superimposed gas phase in the vessel. This
is always the case if the total level never touches the process
fitting.
•
Properties
– Here you can enter the dielectric constant of the upper medium
– As an alternative you can enter the distance to the interface
Adjustment for the level measurement
If you have selected level measurement in the previous menu, then
you can enter the values for the min. and max. adjustment. The value
to be entered refers to the distance from the sealing surface of the
process fitting (sensor reference plane) to the surface of the product.
Adjustment for the level and interface measurement
If you have selected interface measurement in the previous menu,
then you can enter the values for the min. and max. adjustment of
level and interface or accept the values of the level measurement. The
entered value refers to the distance from the sealing surface of the
process fitting (sensor reference plane) to the total level or interface.
Linearization is required if the measured value should be outputted
in proportion to the volume and not the level. The linearization acts
identically on the level and the interface measurement. You can find
further linearization types in the extended adjustment.
If you have a non-linear vessel, you can select here the respective
linearization curve.
Step 3 of 7
Adjustment
Step 4 of 7
Linearization