VEGA VEGAPULS 62 (≥ 2.0.0 - ≥ 4.0.0) Foundation Fieldbus User Manual
Page 66
66
11 Supplement
VEGAPULS 62 • Foundation Fieldbus
36506-EN-121011
Additional deviation through strong, high
frequency electromagnetic fields acc. to
EN 61326
< ±50 mm
Influence of the superimposed gas and pressure to the accuracy
The propagation speed of the radar impulses in gas or vapour above the medium is reduced by
high pressure. This effect depends on the superimposed gas or vapour and is especially large at
low temperatures.
The following table shows the resulting deviation for some typical gases and vapours. The specified
values refer to the distance. Positive values mean that the measured distance is too large, negative
values that the measured distance is too small.
Gas phase
Temperature
Pressure
1 bar
(14.5 psig)
10 bar
(145 psig)
50 bar
(725 psig)
100 bar
(1450 psig)
200 bar
(2900 psig)
Air
20 °C/68 °F
0.00 %
0.22 %
1.2 %
2.4 %
4.9 %
200 °C/392 °F -0.01 %
0.13 %
0.74 %
1.5 %
3.0 %
400 °C/752 °F -0.02 %
0.08 %
0.52 %
1.1 %
2.1 %
Hydrogen
20 °C/68 °F
-0.01 %
0.10 %
0.61 %
1.2 %
2.5 %
200 °C/392 °F -0.02 %
0.05 %
0.37 %
0.76 %
1.6 %
400 °C/752 °F -0.02 %
0.03 %
0.25 %
0.53 %
1.1 %
Steam (satu-
rated steam)
100 °C/212 °F 0.26 %
-
-
-
-
180 °C/356 °F 0.17 %
2.1 %
-
-
-
264 °C/507 °F 0.12 %
1.44 %
9.2 %
-
-
366 °C/691 °F 0.07 %
1.01 %
5.7 %
13.2 %
76.0 %
Characteristics and performance data
Measuring frequency
K-band (26 GHz technology)
Measuring cycle time
Ʋ Standard electronics approx.
450 ms
Ʋ Electronics with increased sensitivity
approx.
700 ms
Step response time
1)
≤ 3 s
Tracking speed of the measuring window
max.
1 m/min
Beam angle
2)
Ʋ Horn antenna ø 40 mm (1.575 in)
20°
Ʋ Horn antenna ø 48 mm (1.89 in)
15°
Ʋ Horn antenna ø 75 mm (2.953 in)
10°
Ʋ Horn antenna ø 95 mm (3.74 in)
8°
Ʋ Parabolic antenna
3°
1)
Time span after a sudden measuring distance change by max. 0.5 m in liquid applications, max 2 m with bulk
solids applications, until the output signal has taken for the first time 90 % of the final value (IEC 61298-2).
2)
Outside the specified beam angle, the energy of the radar signal has a level which is reduced by 50 % (-3 dB)