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Technical data
Reference operating
conditions
Maximum measured error
62
10.1.6
Performance characteristics
• Fluid temperature: +28 °C ± 2 K
• Ambient temperature: +22 °C ± 2 K
• Warm-up period: 30 minutes
Installation:
• Inlet run >10 × DN
• Outlet run > 5 × DN
• Sensor and transmitter grounded.
• The measuring sensors are mounted correctly.
Measured error
The measured error depends on a number of factors. A distinction is made between the measured
error of the device (Prosonic Flow 91 = 0.5 % of the measured value) and an additional installation-
specific measured error (typically 1.5 % of the measured value) that is independent of the device.
The installation-specific measured error depends on the installation conditions on site, such as the
nominal diameter, wall thickness, real pipe geometry, fluid etc. The sum of the two measured errors
is the measured error at the measuring point.
%
3.5
2.0
0.5
0
2
4
6
Fig. 37:
Example of the measured error in a pipe with a nominal diameter DN > 200
a
Measured error of the device (0.5 % o.r. ± 0,02 % o.f.s.
b
Measured error due to installation conditions (typically 1.5 % o.r.)
c
Measured error at the measuring point: 0.5 % o.r. ± 0,02 % o.f.s. + 1.5 % o.r. = 2 % o.r. ± 0,02 % o.f.s.
Measured error at the measuring point
The measured error at the measuring point is made up of the measured error of the device
(0.5 % o.r.) and the measured error resulting from the installation conditions on site. Given a flow
velocity > 0.3 m/s and a Reynolds number > 10000, the following are typical error limits:
Nominal
Device error limits
diameter
DN 50 to 200 ±0.5 % o.r. ± 0.05 % o.f.s.
> DN 200
±0.5 % o.r. ± 0.05 % o.f.s.
o.r. = of reading
o.f.s. = of full scale value (15 m/s)
c
b
a
8
10
12
m/s
Installation-specific
+
error limits (typical)
+
±1.5 % o.r.
+
±1.5 % o.r.
Proline Prosonic Flow 91
Error limits at the measuring point
→
(typical)
→
±2 % o.r. ± 0.05 % o.f.s.
→
±2 % o.r. ± 0.02 % o.f.s.
Endress+Hauser
A0011347
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