VEGA VEGAPULS SR 68 4 … 20 mA_HART - four-wire - Manual (Page 67)

67
11 Supplement
VEGAPULS SR 68 • 4 … 20 mA/HART - four-wire
38295-EN-130624
HART output values
Ʋ PV (Primary Value) Distance to the level
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 Biggest false signal, 20 dB smaller than the useful signal
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. 48: Deviation under reference conditions
1 Reference plane
2 Antenna edge
3 Recommended measuring range
Repeatability ≤ ±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 digital measured value
Temperature drift - Digital output
±3 mm/10 K relating to the max. measuring range or
max. 10 mm
Additional deviation through electromag-
netic interference acc. to EN 61326
< ±50 mm
Specifications apply also to the current output