Volume Calculation; Water Temperature Calculation - Accusonic 8510+ series Reference Manual

3-6 Accusonic Model 8510+ Series Flowmeter
memory. The "learn" routine is implemented by setting the section parameter Learn Path Ratios to 1, and
then setting the flowmeter to run. At the end of 1000 readings, the Learn Path Ratios parameter will
automatically reset to zero. During the learning run, the letter "L" is displayed adjacent to the section Flow
value. The learning run may be curtailed at any time by manually setting the Learn Path Ratios parameter
to 0. Repeating the learning process will erase an old table and create a new one.
In the Path Substitution routine, the contributions towards the total pipe flow from the failed paths is
replaced by a figure generated from the flow contribution from the remaining good paths, weighted as
appropriate by the historic flow contribution ratios for all the paths. Mathematically, the routine can be
represented as:
Flow = Current Flow from Good Paths  Historic Flow / Historic Flow from current good paths.
The Current Flow from Good Paths is = Pipe Area 
paths is set to zero.
Historic Flow is the long time-averaged flow recorded by Learn Path Ratios during flowmeter
commissioning.
Historic Flow from current good paths is = Pipe Area 
components which apply to the paths which are currently failed.

Volume Calculation

Volume is the totalized flow and is computed as:
Volume = Flow in the displayed units  Time elapsed in seconds / Volume Scaling
If the flow is positive, the count will rise to a maximum of 99 999 999, and then reset to zero and start
again.
The Volume figure will be incremented or decremented depending on whether the flow is positive or
negative.
If the count is small, the Volume figure will be displayed as a number with up to 4 decimal places.
The volume counts transmitted by relay closures to an external counter are designed to maintain agreement
between the displayed Volume (in the flowmeter) and the count as registered by the counter.
When the flow is positive, a count is usually transmitted by the relay whenever the Volume increases by
one complete unit. However, if there is a period during which the flow is negative, the Volume figure
displayed in the flowmeter will decrement, but there will be no counts transmitted by the relay. If the flow
should then return positive, no further counts will be transmitted until the Volume figure exceeds the value
which it attained prior to the negative flow period.
In the event of the flowmeter being taken out of the Measure Mode or powered down for a period not
exceeding one hour, the Volume count will be made up for the missing period. The count made up will be
given by: Make-up Count = Flow existing at time of Flowmeter recovery  Down time in Seconds /
Volume Scaling.

Water Temperature Calculation

Water temperature for a section is computed from the average speed of sound in water, as determined from
the measurements made by all the good working paths in the section.
The result is in F if the System Parameter English / Metric is set to "English", and in C if it is set to
"Metric".

V .W in which the velocity from any failed
n n

Historic V .W excluding those historic flow
n n