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Reference Manual
00809-0100-4832, Rev AA
October 2004
Rosemount 3095FC
3-36
• Totalize - The difference between the current value and last hour's
current value is used for point values polled or received as
accumulated values. The Totalization technique assumes that the
value being archived is zeroed out by something else at Contract
Hour and that no rollover of the value occurs. Totalization occurs
at the Minute Historical Log and is summed up for the Hourly and
Daily Historical Logs. A minute after Contract Hour, the current
value is archived. All other minutes are the difference between the
current value and the previous minute's archived value.
• Select Average Type -The Select Average Type parameter is set
to Average, this list appears at the bottom of the screen. Choose
one of the following options to determine how the average value is
calculated.
• Flow Dependant Linear - This is the default method for
calculating the average for the flow input. It is the simplest and
most commonly used method. This method discards samples
for periods when there is no measurable flow and performs a
straightforward (linear) average of the remaining samples to
compute the minute and hour values. The value specified in
the Low Flow Cutoff of the Meter setup determines the values.
When no flow occurs, all values are sampled.
• Flow Dependant Formulaic - Like the Flow-Dependent Linear
method, this method discards samples for periods when there
is no flow. However, in calculating the average, this method
typically takes the square root of each sample before
averaging the samples together and then squares the result.
This formulaic method produces a slightly lower value than the
linear method.
• Flow Weighted Linear - This method does not discard any
samples. Instead, it “weights” each sample by multiplying it by
a flow value (square root of the DP measured during the
sample period), and then performs a linear average by dividing
the sum of the flow-weighted sample by the sum of the flow
values. This results in minute and hourly values that are more
reflective of short periods of high flow.
• Flow Weighted Formulaic - This method combines the
flow-weighting action with the formulaic averaging technique,
both of which were described previously.
9. Select Accumulation Time Basis - When the Selected Archive Type is
Accumulate, this list appears at the bottom of the screen. Choose one
of the following options to determine how the accumulated values are
computed:
• Per Sec - Values summed to compute the second value.
• Per Min - Values summed to compute the minute value.
• Per Hour - Values summed to compute the hourly value.
• Per Day - Values summed to compute the daily value.