VEGA VEGAPULS 65 (≥ 2.0.0 - ≤ 3.8) 4 … 20 mA_HART four-wire - Manual (Page 46)

1,0 m (3.28 ft) 30 m (98.43 ft)
20 mm (0.788 in)
10 mm (0.394 in)
- 10 mm (- 0.394 in)
- 20 mm (- 0.788 in)
0
Fig. 22: Deviation VEGAPULS 65
Influence of the ambient temperature to the sensor electronics 7)
A verage temperature coefficient of the zero
signal (temperature error)
0.03 %/10 K
Influence of the superimposed gas and pressure to the accuracy
T he spreading speed of the radar impulses in gas or vapour above the product is reduced by high
pressures. This effect depends on the superimposed gas or vapour and increases with low
temperatures. The following chart shows the deviation caused by some typical gases or vapours.
T
he stated values refer to the distance. Positive values mean that the measured distance is too
high, negative values that the measured distance is too small.
Gas phase Temperature 1 bar/14.5 psig 10 bar/145 psig 50 bar/725 psig
A ir/Nitrogen 20 °C/68 °F 0.00 % 0.22 % 1.2 %
A ir/Nitrogen 200 °C/392 °F 0.00 % 0.13 % 0.74 %
H ydrogen 20 °C/68 °F -0.01 % 0.10 % 0.61 %
H ydrogen 200 °C/392 °F -0.02 % 0.05 % 0.37 %
W ater (saturated
steam)
100 °C/212 °F 0.20 % - -
W ater (saturated
steam)
180 °C/356 °F - 2.1 % -
Ambient conditions
A mbient, storage and transport temperature -40 … +70 °C (-40 … +158 °F)
Process conditions
F or the vessel pressure, you also have to note the specifications on the type label. Always the
lowest value is applicable.
7) R elating to the nominal measuring range, in the temperature range
-40 … +80 °C .
46 VEGAPULS 65 • 4 … 20 mA/HART four-wire
10 S upplement
28442
-EN
-090305