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Flow-X─ Function Reference
Flow-X General functions - fxPeriodTWA
fxPeriodTWA
Description
The function calculates a time-weighted average (TWA) for a particular period. At the end of a period
the current average is stored in the previous value and the current value is reset to 0.
The function weights the input value with the time (in fact the actual calculation cycle time) and
updates the average accordingly.
Inputs and outputs
Function
inputs
Remark
EU
SW tag
Range
Default
Name
Name used for tag prefix and
retentive storage.
Input value
Value to be averaged
Same
as
linked
cell
-1e11..1e11
Enabled
0: Disabled
1: Enabled
EN
Period type
Type of period:
1: Second
2: Minute
3: Hour
4: Day
5: Week
6: Month
7: Quarter
8: Year
TYP
Period count
Number of periods (e.g. 5 minutes,
8 hours)
CNT
1..1e11
Period start
Absolute start date and time of the
period. This will be used as the
reference point to calculate the
next period rollover from.
The value may be defined in the
past or the future. The next rollover
period will be calculated
accordingly (so forwards or
backwards in time).
START
<DATETIME>
Function
outputs
Remark
EU
SW tag
Alarm
Fallback
Current average
Average calculated over
the current period
Same as input ‘Input
value’
CUR
0
Previous
average
Average of the previous
period
Same as input ‘Input
value’
PRV
0
Pre-previous
average
Average of the pre-
previous period (i.e. the
period before the
previous period)
Same as input ‘Input
value’
PPRV
0
Summary of Contents for flow-x
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