ONICON F-2600 - Manual (Page 16)

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F-2600 & F-2700 Vortex Flow Meter Manual 02/15 - 0808-7 / 19204 Page 16
As shown in Figure 3, F-2600 & F-2700 meters exhibit a constant Strouhal number across
a large range of Reynolds numbers, indicating a consistent linear output over a wide
range of flows and fluid types. Below this linear range, the intelligent electronics in the
meter automatically corrects for the variation in the Strouhal number with the Reynolds
number. The meter’s smart electronics corrects for this non-linearity via its simultaneous
measurements of the process fluid temperature and pressure. This data is then used to
calculate the Reynolds number in real time. The meter automatically corrects down to a
Reynolds number of 5,000.
Figure 3. Reynolds Number Range for the meter
1.2.5 Temperature Measurement
This flow meter uses a 1000 ohm platinum resistance temperature detector (PRTD) to
measure fluid temperature.
1.2.6 Pressure Measurement
Both versions of the meter incorporate a solid-state pressure transducer isolated by a 316
SS diaphragm. The transducer itself is micro-machined silicon, fabricated using integrated
circuit processing technology. A nine-point pressure/temperature calibration is performed
on every sensor. Digital compensation allows these transducers to operate within a 0.3%
of full scale accuracy band within the entire ambient temperature range of -40°F to 140°F
(-40°C to 60°C). Thermal isolation of the pressure transducer ensures the same accuracy
across the allowable process fluid temperature range of -330°F to 750°F (-200°C to 400°C).