VEGA VEGAFLEX 82 4 … 20 mA_HART four-wire - Manual (Page 11)

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3 Product description
VEGAFLEX 82 • 4 … 20 mA/HART - four-wire
41830-EN-130314
The instrument can be supplied in two different electronics versions.
Each electronics version can be identified via the product code on the
type label as well as on the electronics.
•
Standard electronics with operating voltage 90 … 253 V AC;
50/60 Hz: Typ FX80B.-
•
Standard electronics with supply voltage 9.6 … 48 V DC;
20 … 42 V AC: Type FX80I.-
The scope of delivery encompasses:
•
Sensor
•
Documentation
– this operating instructions manual
– Test certificate measuring accuracy (optional)
– Operating instructions manual "Display and adjustment mod-
ule" (optional)
– Supplementary instructions "GSM/GPRS radio module"
(optional)
– Supplementary instructions manual "Heating for display and
adjustment module" (optional)
– Supplementary instructions manual "Plug connector for con-
tinuously measuring sensors" (optional)
– Ex-specific "Safety instructions" (with Ex versions)
– if necessary, further certificates
3.2 Principle of operation
The VEGAFLEX 82 is a level sensor with cable or rod probe for con-
tinuous level measurement, suitable for applications in bulk solids.
High frequency microwave pulses are guided along a steel cable or
a rod. Upon reaching the product surface, the microwave pulses are
reflected. The running time is evaluated by the instrument and output-
ted as level.
Probe end tracking
To increase sensitivity, the probe is equipped with probe end tracking.
In products with a low dielectric constant, this function is very helpful.
This is the case, for example, in plastic granules, packing chips or in
fluidized vessels.
Between a dielectric constant of 1.5 and 3, the function switches on, if
required. As soon as the level echo can no longer be detected, probe
end tracking is automatically activated. The measurement is contin-
ued with the last calculated dielectric constant.
The accuracy thus depends on the stability of the dielectric constant.
If you measure a medium with a dielectric constant below 1.5, probe
end tracking is always active. In this case, you have to enter the
dielectric constant of the medium. A stable dielectric constant is very
important here.
Versions
Scope of delivery
Application area
Functional principle -
level measurement