VEGA VEGAFLEX 81 4 … 20 mA_HART two-wire - Manual (Page 18)

18
4 Mounting
VEGAFLEX 81 • 4 … 20 mA/HART two-wire
41824-EN-130612
vessels, the distance to the vessel wall should be at least 500 mm
(19.7 in).
During operation, the probe must not touch any installations or the
vessel wall. If necessary, fasten the probe end.
In vessels with conical bottom it can be advantageous to mount the
sensor in the center of the vessel, as measurement is then possible
nearly down to the lowest point of the bottom. Keep in mind that
measurement all the way down to the tip of the probe may not be pos-
sible. The exact value of the min. distance (lower dead band) is stated
in chapter "Technical data".
Fig. 7: Vessel with conical bottom
Plastic vessel/Glass vessel
The guided microwave principle requires a metal surface on the pro-
cess fitting. Therefore use in plastic vessels etc. an instrument version
with flange (from DN 50) or place a metal sheet (ø > 200 mm/8 in)
beneath the process fitting when screwing it in.
Make sure that the plate has direct contact with the process fitting.
When installing rod or cable probes in vessels without metal walls,
e.g. in plastic vessels, the measured value can be influenced by
strong electromagnetic fields (emitted interference according to
EN 61326: class A). In this case, use a probe with coaxial version.
Type of vessel