VEGA VEGAPULS 67 (≥ 2.0.0 - ≥ 4.0.0) 4 … 20 mA_HART - four-wire User Manual

Page 23

4 Mounting

VEGAPULS 67 • 4 … 20 mA/HART - four-wire

36532-EN-121011

Fig. 21: Agitators

For level measurements in concrete silos, the sensors are often

mounted in protective boxes. These boxes can be for example metal-

lic, closed subsurface enclosures.
Minimal amounts of stray radiation from the sensor can be reflected

and strengthened by the walls of the subsurface enclosures. In the

case of sensors with plastic housings, this can lead to coupling

disturbances. This is avoided by using sensor housings of aluminium

or stainless steel as well as electromagnetic absorber material in

subsurface enclosures.

Fig. 22: Mounting of the instrument in an subsurface enclosure
1 Subsurface enclosure

2 Concrete bottom

The silo walls of multiple chamber silos are often made of profile

walls, like e.g. profile sheeting, to ensure the required stability. If the

radar sensor is mounted very close to a heavily structured vessel wall,

substantial interfering reflections can be generated. Hence the sensor

should be mounted at a large distance from the separating wall.
The optimum mounting position is on the outer wall of the silo with the

sensor oriented towards the outlet in the silo center.

Installation in subsurface

enclosures

Mounting in multiple

chamber silo