74
11 Supplement
VEGAPULS SR 68 • 4 … 20 mA/HART - two-wire
38294-EN-160707
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, max. 10 mm
Additional deviation through electromag-
netic interference 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 %
Deviation on the current output through analogue/digital conversion
Ʋ
Non-Ex and Ex-ia version
< ±15 µA
Ʋ
Ex-d-ia version
< ±40 µA
Deviation in the current output due to
strong, high-frequency electromagnetic
fields acc. to EN 61326
< ±150 µA
Characteristics and performance data
Measuring frequency
K-band (26 GHz technology)
Measuring cycle time approx.
700 ms
Step response time
3)
≤ 3 s
Beam angle
4)
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°
Emitted HF power (depending on the parameter adjustment)
5)
Ʋ
Average spectral transmission power
density
-14 dBm/MHz EIRP
Ʋ
Max. spectral transmission power
density
+43 dBm/50 MHz EIRP
Ʋ
Max. power density at a distance of
1 m
< 1 µW/cm²
Ambient conditions
Ambient, storage and transport tempera-
ture
-40 … +80 °C (-40 … +176 °F)
3)
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).
4)
Outside the specified beam angle, the energy level of the radar signal is 50% (-3 dB) less.
5)
EIRP: Equivalent Isotropic Radiated Power.