VEGA VEGAPULS 68 (≥ 2.0.0 - ≥ 4.0.0) 4 … 20 mA_HART - two-wire - Manual (Page 67)

67
11 Supplement
VEGAPULS 68 • 4 … 20 mA/HART - two-wire
36535-EN-130205
Ʋ SV (Secondary Value) Level as percentage value
Ʋ TV (Third Value) Linearised percentage value
Ʋ QV (Fourth Value) Scaled measured value
Resolution, digital < 1 mm (0.039 in)
Accuracy (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 Min. distance to installations > 200 mm (7.874 in)
Ʋ Reflector Plane plate reflector
Ʋ False reflections Largest false echo 20 dB smaller than the useful echo
Deviation with liquids See following diagrams
1,0 m (3.28 ft)
10 mm (0.394 in)
2 mm (0.079 in)
- 2 mm (- 0.079 in)
- 10 mm (- 0.394 in)
0
1 2 3
Fig. 54: Deviation under reference conditions
1 Reference plane
2 Antenna edge
3 Recommended measuring range
Reproducibility ≤ ±1 mm
Deviation with bulk solids The values depend to a great extent on the application.
Binding specifications are thus not possible.
Deviation under EMC influence ≤ ±30 mm
Variables influencing measurement accuracy
Specifications apply to the HART signal and the current output
Temperature drift - Digital output
±3 mm/10 K relating to the max. measuring range or
max. 10 mm
Additional deviation through strong, high
frequency electromagnetic fields acc. to
EN 61326
< ±50 mm
Specifications apply also to the current output
Temperature drift - Current output
±0.03 %/10 K relating to the 16 mA span max. ±0.3 %