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186 Acquisition mode
Section 6: Meter operation Reference, Installation, and Operations Manual
June 2013 3-9000-743 Rev S
Smoothing
The Daniel Mark III Ultrasonic Gas Flow Meter meter introduces a method for smoothing the
output (particularly the frequency output) by averaging samples (i.e., waveforms) collected
from past batch periods with new samples for the current batch period.
Smoothing can be applied in the following increments: 0 (i.e., smoothing is disabled), 20, 40,
60, or 80%.
For example, setting Smoothing to 20% means that of the samples used for the current update,
20% will be from previously collected samples and 80% will be from the newly collected
samples. Thus, if 8 new samples are collected, then those 8 samples along with the last 2
previous samples would be used together for the current update period calculations.
Meters are configured by default for Smoothing of 0% (only new samples are used for the
current update period).
6.1.4 Acquisition mode
The Mark III meter has two modes of normal operation: Acquisition and Measurement. The
Acquisition mode is used to acquire the ultrasonic signals. This mode is entered upon powering
up the meter. Once the ultrasonic signals are acquired, the Measurement mode is entered and
the flow velocity is measured. The meter remains in the Measurement mode as long as at least
one chord is operational. If all chords fail while in the Measurement mode, then the Acquisition
mode is re-entered.
The meter operation mode is indicated by the IsAcqMode data point. When TRUE, the meter is
in the Acquisition mode; when FALSE, the meter is in the Measurement mode.
The Acquisition mode uses the chords' “L” dimensions (Laird as appropriate to the meter type)
and the specified minimum and maximum sound velocities (SSMin and SSMax) to determine
the signal search range.