VEGA VEGAFLEX 86 4 … 20 mA_HART - four-wire Coax probe - Manual (Page 17)

17
4 Mounting
VEGAFLEX 86 • 4 … 20 mA/HART - four-wire
42285-EN-130314
listed in chapter "Technical data". Keep in mind for the adjustment that
the default setting for the measuring range refers to water.
The process fitting must be sealed if there is gauge or low pressure in
the vessel. Before use, check if the seal material is resistant against
the measured product and the process temperature.
The max. permissible pressure is specified in chapter "Technical
data" or on the type label of the sensor.
Instruments for a temperature range up to 280 °C or up to 450 °C
have a distance piece between process fitting and electronics hous-
ing. Ths distance piece is used for thermal decoupling of the electron-
ics against high process temperatures.
Information:
The distance piece must only be incorporated up to max. 50 mm (2 in)
in the vessel isolation. Only then, a reliable temperature decoupling is
guaranteed.
1
2
Fig. 8: Mounting of the instrument on insulated vessels.
1 Temperature insulation
2 Ambient temperature on the housing
Vapours, superimposed gases, high pressures and temperature dif-
ferences can change the spreading speed of radar impulses.
There are two possibilities to correct these deviations.
Corrective value in the process control system
In the technical data under "Influence of superimposed gas and pres-
sure on accuracy" you can find a table with deviation values in some
typical gases or in steam.
In the control system (DCS) you can correct the measurement results
of the VEGAFLEX 86 with these values.
Pressure
Mounting in the vessel
insulation
Steam boiler applications