VEGA VEGAFLEX 86 4 … 20 mA_HART two-wire User Manual
Page 88
88
11 Supplement
VEGAFLEX 86 • 4 … 20 mA/HART two-wire
41844-EN-130612
Temperature drift - Current output
±0.03 %/10 K relating to the 16 mA span max. ±0.3 %
Deviation on the current output through
analogue/digital conversion
< ±15 µA
Additional deviation through electromag-
netic interference acc. to EN 61326
< ±150 µA
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
10 bar
(145 psig)
50 bar
(725 psig)
100 bar
(1450 psig)
200 bar
(2900 psig)
400 bar
(5800 psig)
Air
20 °C/68 °F
0.22 %
1.2 %
2.4 %
4.9 %
9.5 %
200 °C/392 °F 0.13 %
0.74 %
1.5 %
3.0 %
6.0 %
400 °C/752 °F 0.08 %
0.52 %
1.1 %
2.1 %
4.2 %
Hydrogen
20 °C/68 °F
0.10 %
0.61 %
1.2 %
2.5 %
4.9 %
200 °C/392 °F 0.05 %
0.37 %
0.76 %
1.6 %
3.1 %
400 °C/752 °F 0.03 %
0.25 %
0.53 %
1.1 %
2.2 %
Steam (satu-
rated steam)
100 °C/212 °F -
-
-
-
-
180 °C/356 °F 2.1 %
-
-
-
-
264 °C/507 °F 1.44 %
9.2 %
-
-
-
366 °C/691 °F 1.01 %
5.7 %
13.2 %
76.0 %
-
Characteristics and performance data
Measuring cycle time
< 500 ms
Step response time
8)
≤ 3 s
Max. filling/emptying speed
1 m/min
Ambient conditions
Ambient, storage and transport tempera-
ture
-40 … +80 °C (-40 … +176 °F)
Process conditions
For the process conditions, please also note the specifications on the type label. The lowest value
always applies.
The measurement error from the process conditions is in the specified pressure and temperature
range of below 1 %.
Vessel pressure relating to the flange
nominal stage
see supplementary instructions manual "Flanges ac-
cording to DIN-EN-ASME-JIS"
8)
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).