UT_STATS — Minimum, maximum and average per period

Keeps min / max / time-weighted average of a value for the current period and the
previous one, for reports, dashboards and IoT uploads.

Pins

	Pin	Type	Default	What to wire
in	`In`	REAL	0.0	Value
in	`Enable`	BOOL	TRUE	Only collect while TRUE (e.g. only while running)
in	`Rollover`	BOOL	FALSE	Rising edge: close the period (e.g. hourly/daily pulse from `UT_SCHEDULE`)
out	`Minimum` / `Maximum` / `Average`	REAL		Current period (0 while it has no samples)
inout	`Data`	UT_STATS_DATA

Field	Type	Default	Meaning
`ignoreBelow` / `ignoreAbove`	REAL	0.0 / 0.0	Values below / above are left out (each 0 = off)
`cmdResetStats`	BOOL		HMI: clear the current and the previous period (acts once, cleared; saved at once)
`minimum`, `maximum`, `average`	REAL		Current period, as the pins
`minimumAt`, `maximumAt`	TIME		Time into the period when the minimum / maximum happened
`samples`	UDINT		Samples counted. 0 = empty period (the values then read 0)
`duration`	TIME		Time collected (`Enable` TRUE)
`prevMinimum`, `prevMaximum`, `prevAverage`, `prevDuration`			The previous period
`prevSamples`	UDINT		0 = the previous period was empty

Time-weighted: the value read each scan stands for the time since the
previous scan, so a value that held for an hour weighs an hour, at any scan rate.
Only samples taken while Enable is TRUE, that are numbers (not NaN or
infinity) and are not left out by ignoreBelow / ignoreAbove count.
Rollover (rising edge) moves the current period to prev* and starts a new one.
A Rollover and a cmdResetStats in the same scan clear everything.
Power cut: nothing is kept. Both periods start empty.
The sum is accurate over long periods (compensated summation), even on boards
where LREAL is 32-bit.

FlowStats(In := Flow.Value, Enable := PumpRunning, Rollover := Clock.DayPulse, Data := FlowStatsCfg);