Technical data

A measure of the signal“quality” is the signal-to-noise ratio (SNR). The higher the SNR, the
better the signal. In general there are two types of noise: “white” noise and “colored”
noise. White noise is noise that occurs across the frequency spectrum and is asynchronous
to the transmitted signal. Colored noise is concentrated around a particular frequency and
can be synchronous with the transmitted signal. The meter provides two methods for
improving the received signal waveform SNR by reducing the noise energy: Stacking and
Filtering.
3.1.4 Stacking
Transducer firing method
Stacking is a method of firing a transducer multiple times and averaging the received
signals on a point-by-point basis. Stacking is effective on asynchronous noise such as is
typically seen with valve noise. This method is not useful for removing synchronous noise
and should not be used when there is a great deal of signal “jitter”. Meters are configured
by default with a stack size of 2. Care should be taken when turning off stacking and it is
recommended to consult with Daniel Customer Service if you are unsure of how stacking a
signal can affect the meter's operation. Refer to Technical Support under the Help menu of
Daniel MeterLink
™
for contact information.
The number of consecutive times to fire each transducer is specified via the StackSize data
point. Available stack sizes are 1 (None), 2, 4, 8, and 16. A stack size of 1 selects no
stacking (i.e., stacking disabled). Stacking is only available when the standard update rate
is selected.
3.1.5 Filtering
Frequency bandpass filter
Filtering applies a bandpass filter that removes noise that is above and below the
transducer frequency. Filtering is effective on noise outside of the frequency passband of
the filter (e.g., filtering works on any noise outside of the passband of the filter). Filtering is
enabled and disabled via the Filter data point (TRUE=enable filtering, FALSE=disable
filtering).
Meters are configured by default with filtering disabled. The minimum emission rate for
the gas meter is 1 milliseconds with the filter ON or OFF. We recommend the default Filter
setting, which is the OFF position.
Care should be taken when enabling and disabling filtering and it is recommended to
consult with Daniel Customer Service if you are unsure of how this change can affect the
meter's operation. Refer to Technical Support under the Help menu of Daniel MeterLink for
contact information.
3.1.6 Batch cycle processing
Batch update period
Flow measurement
16 Daniel 3810 Series Operations Manual