Technical data

Calculation updates performed by the meter, for deriving volume and velocity, are based
on batches of data samples collected from sequences of transducer firings. The batch
update period is dependent upon the user specified batch update period
(SpecBatchUpdtPeriod) and the stack size (StackSize) as shown in Table 4-1. The Standard
batch update period is the default. The actual batch update period is readable via
theBatchUpdatePeriod data point.
Actual meter update periodTable 3-2:
SpecBatch-
UpddtPeriod Stacksize
1 (None) 2 4 8 16
Rapid (250
ms)
0.25 sec N/A N/A N/A N/A
Standard
(1000 ms)
1 sec 1 sec 1.5
sec
3
sec
5 sec
3.2 Smoothing
Smoothing output
The Daniel Liquid Ultrasonic Flow Meter introduces a method for smoothing the output
(particularly the frequency output) by averaging times collected from past batch periods
with new times 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).
3.3 Acquisition mode
Signal acquisition
The Daniel 3810 Series Liquid Ultrasonic Flow 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.
Flow measurement
Operations 17