techmannih/nema34-mounted-stepper-controller

engineering/protection-refinement.json

{
  "revision": "0.4.1-ECO protection refinement",
  "base_commit": "4836266cb3d771da798b0559fe3ae5de7c5905b6",
  "prior_pr_head": "0a8ce71065a9b2d5e641c038b02ca2fb99875a3f",
  "scope": "Integrate main and the reviewed PR #2 safety improvements; retain all main copper, placement, four holes, D20, brake feedback and readable labels.",
  "hardware_qualified": false,
  "motor_operation_authorized": false,
  "order_authorized": false,
  "parts": {
    "R25": {
      "before": "4.22k C49196690",
      "after": "4.99k C7293210",
      "initial_tolerance_fraction": 0.001,
      "tcr_ppm_per_c": 25
    },
    "R61": {
      "before": "16k C860148",
      "after": "16.2k C728583",
      "initial_tolerance_fraction": 0.001,
      "tcr_ppm_per_c": 25
    },
    "R66": {
      "before": "1.21k C705737",
      "after": "1.2k C136970",
      "initial_tolerance_fraction": 0.001,
      "tcr_ppm_per_c": 25
    }
  },
  "current_profile": {
    "global_scaler": 139,
    "irun": 6,
    "max_request_permille": 240,
    "nominal_rms_a": 0.8271367552997603,
    "all_three_qualification_flags": false,
    "runtime_brake_integrity_monitoring": true,
    "runtime_monitor_scope": "Fresh voltage continuity, <=100 ms sample age, <=100 ms braking observation gap, latched failure. Not brake-current measurement, an energy sink or full-current fault qualification."
  },
  "input_budget": {
    "formula_nominal_a": 3.6072144288577155,
    "table_interpolated_nominal_a": 3.625250501002004,
    "min_a": 3.251345740808972,
    "max_a": 4.001781787357958,
    "resistor_tolerance_with_temperature_fraction": 0.0034999999999999996,
    "device_error_allocation_fraction": 0.1,
    "upstream_input_allocation_a": 0.25,
    "total_input_screen_a": 4.251781787357958,
    "remaining_contract_margin_a": 0.7482182126420422,
    "manufacturer_guaranteed_at_selected_resistance": false
  },
  "nominal_motor_input_budget_w": 173.14629258517033,
  "thresholds": {
    "input_uvlo": {
      "min": 42.61912336633663,
      "nominal": 44.4,
      "max": 46.23272181818182
    },
    "input_ovp": {
      "min": 50.9325569583707,
      "nominal": 52.404,
      "max": 53.89272675135474
    },
    "brake_on_screen": {
      "min": 51.378846705081195,
      "nominal": 52.04050000000001,
      "max": 52.64373394120547
    },
    "brake_off_nominal": 51.393040000000006,
    "brake_off_screen": {
      "min": 50.73177802219108,
      "nominal": 51.393040000000006,
      "max": 52.14691389636242
    },
    "independent_reference_envelope_gap": -0.048568900330955955,
    "brake_on_to_cutoff_shared_reference_minimum_gap": 0.10754540065474764,
    "shared_reference_error_v": 0.003725,
    "each_comparator_error_screen_v": 0.00840797902362465,
    "coordination_note": "U13 and U14 share the same U12 output, verified in compiled connectivity. U12 error is common; comparator offset/CMRR/PSRR and resistor errors are independent. Independent absolute envelopes may overlap across different boards. Dynamic separation still requires measurement.",
    "brake_off_above_high_source_and_noise_allocation": 0.031778022191073785,
    "motor_cutoff_screen": {
      "min": 52.59516504087451,
      "nominal": 53.20754716981132,
      "max": 53.825859349397014
    },
    "vsa_operating_max": 50,
    "vs_operating_max": 55,
    "note": "Screening corners, not a qualified min/max specification. Shared reference prevents treating the two trips as independent distributions."
  },
  "stock": {
    "checked_at": "2026-10-13T03:03:27.396Z",
    "counts": {
      "available": 31,
      "unverified-stock": 24,
      "unverified-no-exact-match": 29
    },
    "ordering_approved": false
  },
  "evidence": {
    "geometry": "engineering/protection-refinement-geometry.json",
    "audit": "engineering/power-audit.json",
    "simulation": "engineering/power-eco-simulation/results.json",
    "delivery": "docs/delivery-check.json",
    "verification": "docs/verification.json"
  },
  "open_gates": [
    "Unknown exact-part inventory and reviewed alternatives",
    "Three existing placement advisories",
    "TI PD image and provider programming/readback",
    "Measured source/cable/current/transient coordination",
    "Runtime brake failure, resistor/heatsink/pulse qualification",
    "Actual load/speed/stop duty and thermal soak",
    "Secure mechanical mounting and physical harness qualification"
  ]
}