56
14 Supplement
VEGAPULS 31 • Two-wire 4 … 20 mA/HART
57820-EN-191014
Deviation (according to DIN EN 60770-1)
Process reference conditions according to DIN EN 61298-1
Ʋ Temperature
+18 … +30 °C (+64 … +86 °F)
Ʋ Relative humidity
45 … 75 %
Ʋ Air pressure
860 … 1060 mbar/86 … 106 kPa (12.5 … 15.4 psig)
Installation reference conditions
Ʋ Distance to installations
> 200 mm (7.874 in)
Ʋ Reflector
Flat plate reflector
Ʋ False reflections
Biggest false signal, 20 dB smaller than the useful signal
Deviation with liquids
≤ 2 mm (meas. distance > 0.25 m/0.8202 ft)
Non-repeatability
7)
≤ 2 mm
Deviation with bulk solids
The values depend to a great extent on the application.
Binding specifications are thus not possible.
0,25 m (0.8202 ft)
10 mm (0.3937 in)
- 10 mm (- 0.3937 in)
2 mm (0.079 in)
- 2 mm (- 0.079 in)
0
1 2
3
Fig. 32: Deviation under reference conditions
1 Antenna edge, reference plane
2 Recommended measuring range
Variables influencing measurement accuracy
Specifications apply to the digital measured value
Temperature drift - Digital output
< 3 mm/10 K, max. 10 mm
Specifications apply also to the current output
Temperature drift - Current output
< 0.03 %/10 K or max. 0.3 % relating to the 16.7 mA
span
Deviation in the current output due to
digital/analogue conversion
< 15 µA
Additional deviation through electromagnetic interference
Ʋ According to NAMUR NE 21
< 80 µA
Ʋ According to EN 61326-1
None
Ʋ According to IACS E10 (shipbuilding)/
IEC 60945
< 250 µA
7)
Already included in the meas. deviation
