Technical data

3.1.2 Terminology for flow measurement
Flow measurement terminology
Terminology for ultrasonic flow metersTable 3-1:
Terminology Definition
Sequence A complete cycle of firing all enabled transducers in a single round of trans-
ducer operation (For example, when all eight transducers of the Model 3814
Liquid Ultrasonic Flow Meter have been fired in a single round of operation, it
signifies the completion of one sequence.
Stacking The process of modifying a sequence so that each individual transducer is fired
“x” times (where x equals the stack size) before the next transducer in the se-
quence is fired.
Stack size The multiple number of times each transducer is fired before the next trans-
ducer within the sequence is fired
When stacking is absent or disabled, the stack size is actually 1, because each
enabled transducer is fired once during the sequence. When stacking is ap-
plied or enabled, it is applied increments of 2, 4, 8, and 16 and are the only
stack size choices, so that each enabled transducer is fired 2, 4, 8, or 16 times
before the next transducer in the sequence is fired.)
Emission rate The time elapsed before the next transducer in a sequence is fired, regardless
of stack size (minimum emission rate is 2 milliseconds with the Filter ON or
OFF). We recommend the default Filter setting, which is the OFF position.
Stack emission
rate
The time elapsed before a single transducer is re-fired when stacking is ena-
bled (minimum stack emission rate is 2 milliseconds with the Filter OFF.)
Chords inactive or
active
The exclusion or inclusion of a chord-forming pair of transducers in the se-
quence of transducer operation
Update time The time elapsed, in seconds, between each processing, or recalculation of da-
ta that is collected from sequences of transducer firings
Batch period, or
batch cycle
Synonymous with Update time, as defined above.
Sample Refers to one point on the waveform as in samples per cycle. The data that is
collected from one Sequence of transducer operation (This term is displayed
in the Daniel MeterLink Signal Analyzer screen, and is nearly synonymous with
Sequence, as defined above. That is, Samples/update, as displayed in the Dan-
iel MeterLink Signal Analyzer Wizard, could be interpreted as Sequences/up-
date.) This shows the average number of new samples collected during an up-
date period.
3.1.3 Signal processing
Signal processing for transit time measurement
The signal at the receiving transducer is amplified, digitized and processed digitally to
provide accurate transit time measurement.
Flow measurement
Operations 15