FA-92286 / PLC ladder logic scan cycles / Open access

Two-hand press keeps running after one hand is removed · case 01

The press stroke continues with only one button held.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The single-button branch does not drop the run output.

VERIFIED REPAIR

Drop the run output whenever either button is released.

Unsuccessful approach: Dropping run only when a first-press time was recorded misses presses started simultaneously.

Case contract

Two-hand press control sampled per scan; samples is a list of [t_ms, left, right]. The press may start only when both buttons become pressed within window ms of the first one being pressed (inclusive), starting from a state where both were released. Releasing either button stops the press, and both buttons must then be released before a new start is allowed (anti-tie-down). Return the run output per scan.

Why this case matters

Ladder programs are executed as repeated scans; each defect here changes what a rung, timer, counter or data-table instruction reports on a particular scan, which is how commissioning and field faults are actually observed.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(window, samples):
    first_press = None
    armed = True
    run = False
    out = []
    for t, left, right in samples:
        left = bool(left)
        right = bool(right)
        if not left and not right:
            armed = True
            first_press = None
            run = False
        elif left and right:
            if not run:
                begin = t if first_press is None else first_press
                if armed and t - begin <= window:
                    run = True
                armed = False
        else:
            if first_press is None:
                first_press = t
        out.append(run)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: scenario 1',
   [200,
    [[0, False, False],
     [100, True, True],
     [400, True, True],
     [500, True, True],
     [650, True, True],
     [850, True, True],
     [1050, True, False],
     [1100, False, False],
     [1300, True, True],
     [1600, True, True]]],
   [False, True, True, True, True, True, False, False, True, True]],
  ['regression: scenario 2',
   [200,
    [[0, True, True],
     [50, True, False],
     [200, True, True],
     [250, False, False],
     [300, False, True],
     [400, False, False],
     [450, False, False],
     [550, False, True]]],
   [True, False, False, False, False, False, False, False]],
  ['regression: scenario 3',
   [200,
    [[0, True, False],
     [150, True, True],
     [200, True, True],
     [400, False, False],
     [500, True, True],
     [700, True, True],
     [850, True, False],
     [1000, True, False],
     [1100, False, False],
     [1400, True, False],
     [1450, False, True],
     [1600, True, True],
     [1700, True, True]]],
   [False, True, True, False, True, True, False, False, False, False, False, True, True]]],
 [['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: scenario 1',
   [250,
    [[0, True, True],
     [50, True, True],
     [200, False, True],
     [300, True, True],
     [600, True, True],
     [750, False, True],
     [850, False, False],
     [1000, False, True],
     [1100, True, True]]],
   [True, True, False, False, False, False, False, False, True]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['regression: scenario 2',
   [250,
    [[0, True, True],
     [50, False, True],
     [200, False, False],
     [250, True, False],
     [400, True, True],
     [500, True, True],
     [650, False, False],
     [700, True, True],
     [850, False, False],
     [1000, False, True],
     [1150, False, True],
     [1250, False, True],
     [1550, False, False]]],
   [True, False, False, False, True, True, False, True, False, False, False, False, False]],
  ['regression: scenario 3',
   [500,
    [[0, True, False],
     [300, False, False],
     [400, False, True],
     [500, False, True],
     [800, True, True],
     [950, False, False],
     [1050, False, False],
     [1350, False, False],
     [1450, False, True],
     [1600, False, True],
     [1650, True, True],
     [1800, False, True],
     [1850, False, True]]],
   [False, False, False, False, True, False, False, False, False, False, True, False, False]]],
 [['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['regression: scenario 5',
   [500,
    [[0, True, False],
     [150, False, False],
     [350, True, False],
     [500, False, False],
     [800, True, True],
     [950, False, False],
     [1000, True, True],
     [1200, True, False],
     [1250, False, True],
     [1300, False, True],
     [1450, True, True],
     [1650, True, False],
     [1950, False, False],
     [2250, False, True]]],
   [False, False, False, False, True, False, True, False, False, False, False, False, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['control: scenario 1',
   [200,
    [[0, False, True],
     [100, False, False],
     [250, False, False],
     [300, True, False],
     [400, True, False],
     [450, False, True],
     [550, True, False],
     [700, True, False],
     [800, False, True]]],
   [False, False, False, False, False, False, False, False, False]],
  ['regression: scenario 2',
   [250,
    [[0, False, False],
     [150, False, False],
     [350, False, False],
     [400, True, True],
     [600, True, False],
     [750, False, True],
     [1050, True, True],
     [1150, True, True],
     [1350, True, False],
     [1400, False, False],
     [1550, True, False]]],
   [False, False, False, True, False, False, False, False, False, False, False]]],
 [['regression: scenario 3',
   [200,
    [[0, False, False],
     [300, False, False],
     [350, False, True],
     [650, True, False],
     [700, False, False],
     [1000, False, True],
     [1050, False, False],
     [1150, False, True],
     [1300, True, True],
     [1600, False, True],
     [1700, False, True],
     [1900, False, False],
     [2200, True, True],
     [2250, False, True]]],
   [False, False, False, False, False, False, False, False, True, False, False, False, True, False]],
  ['regression: scenario 8',
   [250,
    [[0, False, True],
     [50, False, False],
     [200, True, True],
     [350, False, False],
     [450, True, True],
     [500, False, True],
     [650, False, True],
     [800, False, False],
     [900, False, False],
     [1000, True, True],
     [1150, False, True],
     [1450, False, True],
     [1500, True, True]]],
   [False, False, True, False, True, False, False, False, False, True, False, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: scenario 1',
   [250,
    [[0, False, True],
     [200, False, False],
     [250, True, False],
     [550, True, False],
     [650, True, True],
     [700, True, False],
     [900, True, True],
     [1100, True, False],
     [1200, False, True],
     [1300, True, False],
     [1450, False, True],
     [1650, False, False],
     [1800, True, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, True]]],
 [['regression: scenario 3',
   [200,
    [[0, False, False],
     [300, False, False],
     [400, True, False],
     [600, True, True],
     [750, True, True],
     [800, True, True],
     [850, True, False],
     [1000, True, True],
     [1150, False, False],
     [1450, False, False]]],
   [False, False, False, True, True, True, False, False, False, False]],
  ['regression: scenario 9',
   [250,
    [[0, True, False],
     [300, True, True],
     [500, False, False],
     [700, False, False],
     [1000, False, True],
     [1150, True, True],
     [1450, True, True],
     [1600, False, True],
     [1900, False, False],
     [2050, True, True],
     [2200, True, False],
     [2350, True, False]]],
   [False, False, False, False, False, True, True, False, False, True, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: scenario 1',
   [500,
    [[0, True, False],
     [150, True, False],
     [250, True, False],
     [300, False, False],
     [350, False, True],
     [650, False, True],
     [850, False, False],
     [1150, False, False],
     [1350, True, False],
     [1650, True, False],
     [1800, True, False],
     [1850, True, False],
     [1900, False, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, False]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: normal cycle	`[False, True, True, True, False, True]`	`[False, True, True, False, False, True]`	Failed
regression: simultaneous press then release one	`[True, True, True]`	`[True, False, False]`	Failed
control: late second hand	`[False, False, False, False, True]`	`[False, False, False, False, True]`	Passed
control: exact window	`[False, True, False]`	`[False, True, False]`	Passed
regression: tie down one button	`[False, True, True, True, True, True]`	`[False, True, False, False, False, False]`	Failed
regression: scenario 1	`[False, True, True, True, True, True, True, False, True, True]`	`[False, True, True, True, True, True, False, False, True, True]`	Failed
regression: scenario 2	`[True, True, True, False, False, False, False, False]`	`[True, False, False, False, False, False, False, False]`	Failed
regression: scenario 3	`[False, True, True, False, True, True, True, True, False, False, False, True, True]`	`[False, True, True, False, True, True, False, False, False, False, False, True, True]`	Failed

SHA-256 / a3e472127f75da82293bc1fd941ea041cc879366ab676dcdd0a2a10f60d37eb6

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(window, samples):
    first_press = None
    armed = True
    run = False
    out = []
    for t, left, right in samples:
        left = bool(left)
        right = bool(right)
        if not left and not right:
            armed = True
            first_press = None
            run = False
        elif left and right:
            if not run:
                begin = t if first_press is None else first_press
                if armed and t - begin <= window:
                    run = True
                armed = False
        else:
            run = run and first_press is None
            if first_press is None:
                first_press = t
        out.append(run)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: scenario 1',
   [200,
    [[0, False, False],
     [100, True, True],
     [400, True, True],
     [500, True, True],
     [650, True, True],
     [850, True, True],
     [1050, True, False],
     [1100, False, False],
     [1300, True, True],
     [1600, True, True]]],
   [False, True, True, True, True, True, False, False, True, True]],
  ['regression: scenario 2',
   [200,
    [[0, True, True],
     [50, True, False],
     [200, True, True],
     [250, False, False],
     [300, False, True],
     [400, False, False],
     [450, False, False],
     [550, False, True]]],
   [True, False, False, False, False, False, False, False]],
  ['regression: scenario 3',
   [200,
    [[0, True, False],
     [150, True, True],
     [200, True, True],
     [400, False, False],
     [500, True, True],
     [700, True, True],
     [850, True, False],
     [1000, True, False],
     [1100, False, False],
     [1400, True, False],
     [1450, False, True],
     [1600, True, True],
     [1700, True, True]]],
   [False, True, True, False, True, True, False, False, False, False, False, True, True]]],
 [['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: scenario 1',
   [250,
    [[0, True, True],
     [50, True, True],
     [200, False, True],
     [300, True, True],
     [600, True, True],
     [750, False, True],
     [850, False, False],
     [1000, False, True],
     [1100, True, True]]],
   [True, True, False, False, False, False, False, False, True]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['regression: scenario 2',
   [250,
    [[0, True, True],
     [50, False, True],
     [200, False, False],
     [250, True, False],
     [400, True, True],
     [500, True, True],
     [650, False, False],
     [700, True, True],
     [850, False, False],
     [1000, False, True],
     [1150, False, True],
     [1250, False, True],
     [1550, False, False]]],
   [True, False, False, False, True, True, False, True, False, False, False, False, False]],
  ['regression: scenario 3',
   [500,
    [[0, True, False],
     [300, False, False],
     [400, False, True],
     [500, False, True],
     [800, True, True],
     [950, False, False],
     [1050, False, False],
     [1350, False, False],
     [1450, False, True],
     [1600, False, True],
     [1650, True, True],
     [1800, False, True],
     [1850, False, True]]],
   [False, False, False, False, True, False, False, False, False, False, True, False, False]]],
 [['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['regression: scenario 5',
   [500,
    [[0, True, False],
     [150, False, False],
     [350, True, False],
     [500, False, False],
     [800, True, True],
     [950, False, False],
     [1000, True, True],
     [1200, True, False],
     [1250, False, True],
     [1300, False, True],
     [1450, True, True],
     [1650, True, False],
     [1950, False, False],
     [2250, False, True]]],
   [False, False, False, False, True, False, True, False, False, False, False, False, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['control: scenario 1',
   [200,
    [[0, False, True],
     [100, False, False],
     [250, False, False],
     [300, True, False],
     [400, True, False],
     [450, False, True],
     [550, True, False],
     [700, True, False],
     [800, False, True]]],
   [False, False, False, False, False, False, False, False, False]],
  ['regression: scenario 2',
   [250,
    [[0, False, False],
     [150, False, False],
     [350, False, False],
     [400, True, True],
     [600, True, False],
     [750, False, True],
     [1050, True, True],
     [1150, True, True],
     [1350, True, False],
     [1400, False, False],
     [1550, True, False]]],
   [False, False, False, True, False, False, False, False, False, False, False]]],
 [['regression: scenario 3',
   [200,
    [[0, False, False],
     [300, False, False],
     [350, False, True],
     [650, True, False],
     [700, False, False],
     [1000, False, True],
     [1050, False, False],
     [1150, False, True],
     [1300, True, True],
     [1600, False, True],
     [1700, False, True],
     [1900, False, False],
     [2200, True, True],
     [2250, False, True]]],
   [False, False, False, False, False, False, False, False, True, False, False, False, True, False]],
  ['regression: scenario 8',
   [250,
    [[0, False, True],
     [50, False, False],
     [200, True, True],
     [350, False, False],
     [450, True, True],
     [500, False, True],
     [650, False, True],
     [800, False, False],
     [900, False, False],
     [1000, True, True],
     [1150, False, True],
     [1450, False, True],
     [1500, True, True]]],
   [False, False, True, False, True, False, False, False, False, True, False, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: scenario 1',
   [250,
    [[0, False, True],
     [200, False, False],
     [250, True, False],
     [550, True, False],
     [650, True, True],
     [700, True, False],
     [900, True, True],
     [1100, True, False],
     [1200, False, True],
     [1300, True, False],
     [1450, False, True],
     [1650, False, False],
     [1800, True, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, True]]],
 [['regression: scenario 3',
   [200,
    [[0, False, False],
     [300, False, False],
     [400, True, False],
     [600, True, True],
     [750, True, True],
     [800, True, True],
     [850, True, False],
     [1000, True, True],
     [1150, False, False],
     [1450, False, False]]],
   [False, False, False, True, True, True, False, False, False, False]],
  ['regression: scenario 9',
   [250,
    [[0, True, False],
     [300, True, True],
     [500, False, False],
     [700, False, False],
     [1000, False, True],
     [1150, True, True],
     [1450, True, True],
     [1600, False, True],
     [1900, False, False],
     [2050, True, True],
     [2200, True, False],
     [2350, True, False]]],
   [False, False, False, False, False, True, True, False, False, True, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: scenario 1',
   [500,
    [[0, True, False],
     [150, True, False],
     [250, True, False],
     [300, False, False],
     [350, False, True],
     [650, False, True],
     [850, False, False],
     [1150, False, False],
     [1350, True, False],
     [1650, True, False],
     [1800, True, False],
     [1850, True, False],
     [1900, False, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, False]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: normal cycle	`[False, True, True, False, False, True]`	`[False, True, True, False, False, True]`	Passed
regression: simultaneous press then release one	`[True, True, True]`	`[True, False, False]`	Failed
control: late second hand	`[False, False, False, False, True]`	`[False, False, False, False, True]`	Passed
control: exact window	`[False, True, False]`	`[False, True, False]`	Passed
regression: tie down one button	`[False, True, False, False, False, False]`	`[False, True, False, False, False, False]`	Passed
regression: scenario 1	`[False, True, True, True, True, True, True, False, True, True]`	`[False, True, True, True, True, True, False, False, True, True]`	Failed
regression: scenario 2	`[True, True, True, False, False, False, False, False]`	`[True, False, False, False, False, False, False, False]`	Failed
regression: scenario 3	`[False, True, True, False, True, True, True, False, False, False, False, True, True]`	`[False, True, True, False, True, True, False, False, False, False, False, True, True]`	Failed

SHA-256 / 23727c2add1fe8b971dfd277379179afb140f93bf679fe764eb1aa9842b6ed82

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(window, samples):
    first_press = None
    armed = True
    run = False
    out = []
    for t, left, right in samples:
        left = bool(left)
        right = bool(right)
        if not left and not right:
            armed = True
            first_press = None
            run = False
        elif left and right:
            if not run:
                begin = t if first_press is None else first_press
                if armed and t - begin <= window:
                    run = True
                armed = False
        else:
            run = False
            if first_press is None:
                first_press = t
        out.append(run)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: scenario 1',
   [200,
    [[0, False, False],
     [100, True, True],
     [400, True, True],
     [500, True, True],
     [650, True, True],
     [850, True, True],
     [1050, True, False],
     [1100, False, False],
     [1300, True, True],
     [1600, True, True]]],
   [False, True, True, True, True, True, False, False, True, True]],
  ['regression: scenario 2',
   [200,
    [[0, True, True],
     [50, True, False],
     [200, True, True],
     [250, False, False],
     [300, False, True],
     [400, False, False],
     [450, False, False],
     [550, False, True]]],
   [True, False, False, False, False, False, False, False]],
  ['regression: scenario 3',
   [200,
    [[0, True, False],
     [150, True, True],
     [200, True, True],
     [400, False, False],
     [500, True, True],
     [700, True, True],
     [850, True, False],
     [1000, True, False],
     [1100, False, False],
     [1400, True, False],
     [1450, False, True],
     [1600, True, True],
     [1700, True, True]]],
   [False, True, True, False, True, True, False, False, False, False, False, True, True]]],
 [['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: scenario 1',
   [250,
    [[0, True, True],
     [50, True, True],
     [200, False, True],
     [300, True, True],
     [600, True, True],
     [750, False, True],
     [850, False, False],
     [1000, False, True],
     [1100, True, True]]],
   [True, True, False, False, False, False, False, False, True]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['regression: scenario 2',
   [250,
    [[0, True, True],
     [50, False, True],
     [200, False, False],
     [250, True, False],
     [400, True, True],
     [500, True, True],
     [650, False, False],
     [700, True, True],
     [850, False, False],
     [1000, False, True],
     [1150, False, True],
     [1250, False, True],
     [1550, False, False]]],
   [True, False, False, False, True, True, False, True, False, False, False, False, False]],
  ['regression: scenario 3',
   [500,
    [[0, True, False],
     [300, False, False],
     [400, False, True],
     [500, False, True],
     [800, True, True],
     [950, False, False],
     [1050, False, False],
     [1350, False, False],
     [1450, False, True],
     [1600, False, True],
     [1650, True, True],
     [1800, False, True],
     [1850, False, True]]],
   [False, False, False, False, True, False, False, False, False, False, True, False, False]]],
 [['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['regression: scenario 5',
   [500,
    [[0, True, False],
     [150, False, False],
     [350, True, False],
     [500, False, False],
     [800, True, True],
     [950, False, False],
     [1000, True, True],
     [1200, True, False],
     [1250, False, True],
     [1300, False, True],
     [1450, True, True],
     [1650, True, False],
     [1950, False, False],
     [2250, False, True]]],
   [False, False, False, False, True, False, True, False, False, False, False, False, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['control: scenario 1',
   [200,
    [[0, False, True],
     [100, False, False],
     [250, False, False],
     [300, True, False],
     [400, True, False],
     [450, False, True],
     [550, True, False],
     [700, True, False],
     [800, False, True]]],
   [False, False, False, False, False, False, False, False, False]],
  ['regression: scenario 2',
   [250,
    [[0, False, False],
     [150, False, False],
     [350, False, False],
     [400, True, True],
     [600, True, False],
     [750, False, True],
     [1050, True, True],
     [1150, True, True],
     [1350, True, False],
     [1400, False, False],
     [1550, True, False]]],
   [False, False, False, True, False, False, False, False, False, False, False]]],
 [['regression: scenario 3',
   [200,
    [[0, False, False],
     [300, False, False],
     [350, False, True],
     [650, True, False],
     [700, False, False],
     [1000, False, True],
     [1050, False, False],
     [1150, False, True],
     [1300, True, True],
     [1600, False, True],
     [1700, False, True],
     [1900, False, False],
     [2200, True, True],
     [2250, False, True]]],
   [False, False, False, False, False, False, False, False, True, False, False, False, True, False]],
  ['regression: scenario 8',
   [250,
    [[0, False, True],
     [50, False, False],
     [200, True, True],
     [350, False, False],
     [450, True, True],
     [500, False, True],
     [650, False, True],
     [800, False, False],
     [900, False, False],
     [1000, True, True],
     [1150, False, True],
     [1450, False, True],
     [1500, True, True]]],
   [False, False, True, False, True, False, False, False, False, True, False, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: scenario 1',
   [250,
    [[0, False, True],
     [200, False, False],
     [250, True, False],
     [550, True, False],
     [650, True, True],
     [700, True, False],
     [900, True, True],
     [1100, True, False],
     [1200, False, True],
     [1300, True, False],
     [1450, False, True],
     [1650, False, False],
     [1800, True, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, True]]],
 [['regression: scenario 3',
   [200,
    [[0, False, False],
     [300, False, False],
     [400, True, False],
     [600, True, True],
     [750, True, True],
     [800, True, True],
     [850, True, False],
     [1000, True, True],
     [1150, False, False],
     [1450, False, False]]],
   [False, False, False, True, True, True, False, False, False, False]],
  ['regression: scenario 9',
   [250,
    [[0, True, False],
     [300, True, True],
     [500, False, False],
     [700, False, False],
     [1000, False, True],
     [1150, True, True],
     [1450, True, True],
     [1600, False, True],
     [1900, False, False],
     [2050, True, True],
     [2200, True, False],
     [2350, True, False]]],
   [False, False, False, False, False, True, True, False, False, True, False, False]],
  ['regression: normal cycle',
   [500,
    [[0, True, False],
     [300, True, True],
     [400, True, True],
     [500, False, True],
     [600, False, False],
     [700, True, True]]],
   [False, True, True, False, False, True]],
  ['control: late second hand',
   [200, [[0, True, False], [300, True, True], [400, False, False], [500, True, False], [600, True, True]]],
   [False, False, False, False, True]],
  ['control: exact window',
   [200, [[0, False, True], [200, True, True], [300, False, False]]],
   [False, True, False]],
  ['regression: tie down one button',
   [200,
    [[0, True, False],
     [100, True, True],
     [200, True, False],
     [300, True, True],
     [400, True, False],
     [450, True, True]]],
   [False, True, False, False, False, False]],
  ['regression: simultaneous press then release one',
   [200, [[0, True, True], [100, True, False], [200, True, True]]],
   [True, False, False]],
  ['control: scenario 1',
   [500,
    [[0, True, False],
     [150, True, False],
     [250, True, False],
     [300, False, False],
     [350, False, True],
     [650, False, True],
     [850, False, False],
     [1150, False, False],
     [1350, True, False],
     [1650, True, False],
     [1800, True, False],
     [1850, True, False],
     [1900, False, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, False]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: normal cycle	`[False, True, True, False, False, True]`	`[False, True, True, False, False, True]`	Passed
regression: simultaneous press then release one	`[True, False, False]`	`[True, False, False]`	Passed
control: late second hand	`[False, False, False, False, True]`	`[False, False, False, False, True]`	Passed
control: exact window	`[False, True, False]`	`[False, True, False]`	Passed
regression: tie down one button	`[False, True, False, False, False, False]`	`[False, True, False, False, False, False]`	Passed
regression: scenario 1	`[False, True, True, True, True, True, False, False, True, True]`	`[False, True, True, True, True, True, False, False, True, True]`	Passed
regression: scenario 2	`[True, False, False, False, False, False, False, False]`	`[True, False, False, False, False, False, False, False]`	Passed
regression: scenario 3	`[False, True, True, False, True, True, False, False, False, False, False, True, True]`	`[False, True, True, False, True, True, False, False, False, False, False, True, True]`	Passed

SHA-256 / 8fdd4086b1d84e8cc737d0c0a03f9ba3cfd6c2f7280755ea68a02ffbae09f103

Verification & scope

A deterministic bounded teaching model of one PLC instruction or rung pattern evaluated scan by scan. The stated contract is a stipulated toy convention, not a claim of conformance to any vendor controller or IEC 61131-3 runtime. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:51:44.337352+00:00.

Case digest / 64eaa34b3111ae6b5349c506930c9414c7dd220092d74bf46e7e467546ba3ff1