UT_ROTATION — Shaft / belt speed monitor (proximity sensor)

Watches a proximity sensor on a shaft, pulley or target wheel. It detects a stall
(sensor stuck on or off), underspeed (belt slip, overload) and overspeed, and
measures the speed: shaft speed in rpm or rev/s, or belt / chain line speed in
m/min or m/s. Wire Healthy to the motor's Interlock to stop on a stall.
Replaces rotationMonitor (Better Eggs).

Pins

	Pin	Type	Default	What to wire
in	`Running`	BOOL	FALSE	Machine running (`UT_MOTOR.Running`)
in	`Sensor`	BOOL	FALSE	Proximity sensor
in	`Reset`	BOOL	FALSE	Rising edge: reset a latched fault
out	`Healthy`	BOOL		No fault → motor `Interlock`
out	`Rotating`	BOOL		Pulses being seen (one within `stallTime`)
out	`Speed`	REAL		In `speedUnit` (rpm by default)
out	`Fault`	BOOL
inout	`Data`	UT_ROTATION_DATA

Record `UT_ROTATION_DATA`

Field	Type	Default	Meaning
`pulsesPerRev`	INT	1	Targets on the wheel, for rpm and rev/s (0 or negative counts as 1)
`speedUnit`	UT_SPEED_UNIT	UT_SPD_RPM	Unit of `Speed`, `speed`, `minSpeed` and `maxSpeed`: `UT_SPD_RPM` (0, rpm), `UT_SPD_RPS` (revolutions per second = Hz of the shaft), `UT_SPD_M_MIN` (line speed, m/min), `UT_SPD_M_S` (line speed, m/s)
`distPerPulse`	REAL	0.0	Line speed only: belt or chain travel per pulse, in m (e.g. a 0.3 m drum circumference with 2 targets = 0.15). Must be above 0 for m/min and m/s
`startDelay`	TIME	T#5s	After a start, stall and underspeed are ignored this long
`stallTime`	TIME	T#3s	No pulse this long while running = stalled
`minSpeed` / `maxSpeed`	REAL	0.0 / 0.0	Under / over speed limits, in `speedUnit` (0 = off)
`speedDelay`	TIME	T#5s	Under / over speed must last this long
`filterTime`	TIME	T#1s	Speed is measured over at least this long
`coastDown`	TIME	T#10s	After a stop, pulses are expected this long
`retryWindow`	TIME	T#1h	RETRY counts trips within this window
`stall`	UT_PROTECTION	TRIP · MANUAL	b0: a stalled conveyor usually needs a look
`underspeed`	UT_PROTECTION	WARN · AUTO	b1: belt slip
`overspeed`	UT_PROTECTION	OFF	b2
`sensor`	UT_PROTECTION	WARN · AUTO	b3: pulses while stopped, after `coastDown`
(invalid setting)		warning	b4: `wrnConfig`, see below
`cmdReset`	BOOL		HMI reset (acts once, on its rising edge; cleared by the block)
`speed`, `rotating`, `period`	REAL, BOOL, TIME		Status (`speed` in `speedUnit`; `period`: time between the last two pulses)
`wrnTooFast`	BOOL		Pulses at the scan-rate limit (held 5 s)
`wrnConfig`	BOOL		`speedUnit` unknown, or a line speed with `distPerPulse` not above 0 (or not a number)
`fault`, `warning`, `faultCode`	BOOL, BOOL, DWORD		See conventions
`timeLeft`	TIME		The countdown the status shows: the start delay, or a recover / retry wait
`statusCode`	UT_STATUS		What it is doing, or what is wrong (codes below)
`faultId`	UT_FAULT		The fault, warning or setting the status is about (`UT_F_NONE` when none)
`statusText`	STRING(30)		`statusCode` and `faultId` in words, e.g. `Latched: stalled`

Status codes

statusCode is a UT_STATUS and faultId a UT_FAULT (an HMI reads their numbers); statusText is the two in words.

`statusCode`	`faultId`	`statusText`	When
`UT_ST_STOPPED`		`Stopped`	Not running, no pulses
`UT_ST_RUNNING`		`Running`	Running, past the start delay, no fault
`UT_ST_STILL_TURNING`		`Stopped: still turning`	Not running, pulses still seen (coasting down)
`UT_ST_CHECKS_DELAY`		`Starting: checks delayed`	Running, inside `startDelay` (`timeLeft` counts it down)
`UT_ST_WARNING`	`UT_F_PULSES_FAST`	`Warning: pulses too fast`	`wrnTooFast`
`UT_ST_WARNING`	the protection	`Warning: stalled`	A protection set to WARN: `UT_F_STALLED` (stalled), `UT_F_UNDERSPEED`, `UT_F_OVERSPEED`, `UT_F_PULSES_STOPPED` (turning when off)
`UT_ST_WARN_SETTING`	`UT_F_SPEED_UNIT` / `UT_F_DIST_PER_PULSE`	`Setting: speed unit`	`wrnConfig`
`UT_ST_FAULT`	the protection	`Fault: stalled`	A trip, AUTO reset (`timeLeft`: the recover still to go)
`UT_ST_FAULT_RETRY`	the protection	`Retrying: stalled`	A trip, RETRY with retries left (`timeLeft`: the wait)
`UT_ST_FAULT_LOCKED`	the protection	`Locked: stalled`	A trip, RETRY, retries used up: reset needed
`UT_ST_FAULT_RESET`	the protection	`Latched: stalled`	A trip, MANUAL: reset needed

A trip comes first, then a warning, a bad setting, pulses too fast, starting,
running, coasting, stopped.

How it works

The pulse rate f (pulses per second) is measured from pulse to pulse over at
least filterTime, so a slow shaft is accurate. While no pulse comes it falls
(1 / time since the last pulse), so a stopping shaft is seen slowing; after
stallTime it is 0. The speed, and the limits, are in speedUnit:

`speedUnit`	Speed
`UT_SPD_RPM` (default)	rpm = 60 × f / `pulsesPerRev`
`UT_SPD_RPS`	rev/s (Hz) = f / `pulsesPerRev`
`UT_SPD_M_MIN`	m/min = 60 × f × `distPerPulse`
`UT_SPD_M_S`	m/s = f × `distPerPulse`

This divides by pulsesPerRev; the original multiplied.

Example, a conveyor that should run at 45 m/min, with one target on a tail
drum of 0.4 m circumference: speedUnit := UT_SPD_M_MIN, distPerPulse := 0.4, minSpeed := 35.0 (belt slip below 35 m/min). The same drum in rpm:
minSpeed := 87.5 (35 / 0.4).
The maximum measurable rate is set by the scan rate: 1 / (2 × scan time)
pulses per second (60 / (2 × scan time × pulsesPerRev) rpm). The block warns
(wrnTooFast) at it.
Invalid settings. An unknown speedUnit, or a line speed with
distPerPulse 0, negative or not a number, sets wrnConfig, warning and
fault bit 4 (status Setting: speed unit or
Setting: distance per pulse): the speed reads 0 and the under / over
speed checks are off until it is fixed. The stall and sensor checks still act.
A stall is seen with the sensor stuck ON or stuck OFF (no rising edge either way).
Each protection is a UT_PROTECTION: change its response and reset as you like.
Reset by the Reset pin or cmdReset, each on its rising edge: one held on (a
Modbus coil left on) resets once; a reset while the shaft is still stalled is
refused.

OpenPLC

UT_ROTATION — Shaft / belt speed monitor (proximity sensor)

Pins

Record UT_ROTATION_DATA

Status codes

How it works

Record `UT_ROTATION_DATA`