62
Reference Manual
00809-0100-4772, Rev FA
Transducer Block
March 2016
Transducer Block
4.4.5 Filtering
Flow rate value
Flow Rate Value is the actual measured flow rate in the line. On the bench, the value should
be zero. Check the units of the value to make sure they are configured correctly. The unit
configuration is contained in the AI block.
Shedding frequency
Shedding Frequency is a direct indication of the shedding “vortices” across the shedder bar.
Sensor signal strength
Sensor Signal Strength is a variable that indicates the flow signal strength. This value
indicates if there is enough flow signal strength for the meter to work properly. For accurate
flow measurement, ideally the value should be greater than 4.0. Values greater than 4.0 will
allow increased filtering for noisy applications. Values less than 4.0 may indicate
applications with very low densities and/or applications with excessive filtering.
Lowpass corner
The Lowpass Corner filter sets the low-pass corner frequency to minimize the effects of high
frequency noise. It is factory set based on line size and service type. Adjustments may be
required only if there are problems.
Low flow cutoff
The Low Flow Cutoff enables adjustment of the filter for noise at no flow. It is set at the
factory to handle most applications, but certain applications may require adjustment either
to expand measurability or to reduce noise. It also includes a dead band such that once flow
goes below the cutoff value, output does not return to the normal flow range until flow
goes above the dead band.
Filter trigger level
Filter Trigger Level is configured to reject noise within the flow range while allowing normal
amplitude variation of the vortex signal. Signals of amplitude lower than the Filter Trigger
Level setting are filtered out. The default factory setting of “4” is optimized to work best
with most applications.
Filter auto adjust
The Filter Auto Adjust is a function that can be used to optimize the range of the flowmeter
based on the density of the fluid. The electronics uses process density to calculate the
minimum measurable flow rate, while retaining at least a 4.0 signal strength value.
Required process density
The Required Process Density is calculated from the filter settings. It is the process density
that is required to obtain an adequate sensor signal.
To Next Page
Loading...
