Siemens SITRANS FUS1010 NEMA-4X/ IP 65 Clamp-On Multi-Function Flowmeter Manual De Usuario
5-3
1010NFM-3J
Section 5
within specifications depends primarily on the receive signal’s signal-to-noise ratio and amplitude. The
information below may point to application conditions that could reduce system performance below its
normally high level.
information below may point to application conditions that could reduce system performance below its
normally high level.
5.3.5 ACCURACY
Although system accuracy is exceptional over a wide turndown ratio, at extremely low flow rates, a
small zero offset becomes a high percentage of actual flow. Obviously, the ultimate accuracy will be
obtained by performing an on-site flow calibration. A flow calibration can increase system accuracy to
between 0.3% to 0.5%, depending on application conditions.
small zero offset becomes a high percentage of actual flow. Obviously, the ultimate accuracy will be
obtained by performing an on-site flow calibration. A flow calibration can increase system accuracy to
between 0.3% to 0.5%, depending on application conditions.
Two common data-entry mistakes may reduce performance. If you enter an incorrect liquid viscosity
value, you could compromise the intrinsic flow profile compensation curve. Incorrectly identifying the
transducers will reduce accuracy. Measured sonic velocity (Vs) errors will usually reveal this problem
and by simply returning to the appropriate menu cells, entering the correct values, and then repeating
the transducer installation it will resolve it.
value, you could compromise the intrinsic flow profile compensation curve. Incorrectly identifying the
transducers will reduce accuracy. Measured sonic velocity (Vs) errors will usually reveal this problem
and by simply returning to the appropriate menu cells, entering the correct values, and then repeating
the transducer installation it will resolve it.
5.3.6 REPEATABILITY
Some applications require repeatability rather than absolute accuracy. System 1010 features excellent
repeatability specifications since its digital “no moving parts” design avoids the adverse effects of
hysteresis and other wear mechanisms typical of mechanical devices.
repeatability specifications since its digital “no moving parts” design avoids the adverse effects of
hysteresis and other wear mechanisms typical of mechanical devices.
5.3.7 DATA STABILITY
Two main factors influence the system’s data stability: Data Scatter and Drift.
Data Scatter
Data scatter is a rapid variation in flow readings (within a span of about 0.1 to 5 seconds). Minimal data
scatter (approximately 0.01 to 0.03 ft/sec) is a natural by-product of digital computation that extracts
the extremely small difference in the up vs. down sonic transit time. Minimal data scatter will not influ-
ence the integrated flow total over periods as short as several minutes. Naturally, it will be a greater
percentage of the reading when the meter measures extremely low flow rates. Poor liquid sonic con-
ductivity may attenuate sonic signal to a level that increases data scatter. You should check the signal
level (Valc %) item on the Diagnostic Menu. Usually, this is indicated by a low Valc % value (less than
30).
scatter (approximately 0.01 to 0.03 ft/sec) is a natural by-product of digital computation that extracts
the extremely small difference in the up vs. down sonic transit time. Minimal data scatter will not influ-
ence the integrated flow total over periods as short as several minutes. Naturally, it will be a greater
percentage of the reading when the meter measures extremely low flow rates. Poor liquid sonic con-
ductivity may attenuate sonic signal to a level that increases data scatter. You should check the signal
level (Valc %) item on the Diagnostic Menu. Usually, this is indicated by a low Valc % value (less than
30).
System 1010 does not exhibit inertia since it has no moving parts. In addition, it takes readings ten
times per second. Therefore, it can detect and track very brief flow fluctuations that are beyond the
response capability of some conventional meters. This performance level is required for detecting very
fast and short flow transients or for a fast-response servo control loop application. However, you can
use the damping and slewing controls to smooth the output response if you want the system to ignore
rapid flow fluctuations or data scatter.
times per second. Therefore, it can detect and track very brief flow fluctuations that are beyond the
response capability of some conventional meters. This performance level is required for detecting very
fast and short flow transients or for a fast-response servo control loop application. However, you can
use the damping and slewing controls to smooth the output response if you want the system to ignore
rapid flow fluctuations or data scatter.
Data Drift
Drift is a defined as a long-term cyclical flow deviation resulting from the variation of liquid temperature
or liquid sonic velocity. Drift may be more noticeable when combined with a poor signal-to-noise ratio.
System 1010 is carefully designed to minimize the effects of drift. There are no drift-prone analog
phase-locked loop devices in the primary detection circuits. In addition, we use only the most stable
plastics or steel to construct our transducers.
or liquid sonic velocity. Drift may be more noticeable when combined with a poor signal-to-noise ratio.
System 1010 is carefully designed to minimize the effects of drift. There are no drift-prone analog
phase-locked loop devices in the primary detection circuits. In addition, we use only the most stable
plastics or steel to construct our transducers.