VEGA VEGAFLEX 81 4 … 20 mA_HART - four-wire Coax probe - Manual (Page 10)

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3 Product description
VEGAFLEX 81 • 4 … 20 mA/HART - four-wire
42280-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 81 is a level sensor with coax probe for continuous
level or interface measurement, suitable for applications in liquids.
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.
d
h
1
Fig. 4: Level measurement
1 Sensor reference plane (seal surface of the process fitting)
d Distance to the interface (HART value 1)
h Height - Level
Versions
Scope of delivery
Application area
Functional principle -
level measurement