techmannih/nema34-mounted-stepper-controller

engineering/power-thermal-eco.json

{
  "revision": "0.4.1-ECO",
  "base_commit": "16d1347fc9991399f7ff5ea089966af2876fc3ad",
  "authorization": "2026-10-13 user requested implementation, commit/push as techmannih and reference-based initial limits.",
  "status": "power-thermal-eco-order-held",
  "hardware_qualified": false,
  "changes": {
    "U6": {
      "before": "TPS26631RGER / C1850273",
      "after": "TPS26630RGER / C1850276",
      "mode": "Pin 11 left open: 1x active limiting then latch-off; eliminates 2x overload interval."
    },
    "R25": {
      "before": "4.02 kohm",
      "after": "4.22 kohm / C49196690 / 0.1% / 100 ppm/C",
      "nominal_limit_a": 4.265402843601896,
      "screened_max_limit_a": 4.6378169341428706
    },
    "R66": {
      "before": "1 kohm",
      "after": "1.21 kohm / C705737 / 0.1% / 25 ppm/C",
      "cutoff_nominal_v": 53.183639792550686
    },
    "D20": {
      "part": "GOODWORK SS10100 SMBF / C49242208",
      "rating": "100 V / 10 A",
      "cathode_pin_1": "VMOTOR",
      "anode_pin_2": "BRAKE_RETURN",
      "pcb_trace_width_mm": 2.4,
      "purpose": "Local recirculation path for brake cable inductance; actual switching waveforms remain unmeasured."
    },
    "feedback": {
      "R134_R135": "4.7 kohm 1206 250 mW C6675858 each",
      "R136": "510 ohm 0603 C7468460",
      "C98": "10 nF 0603 C57112",
      "adc": "U30 AIN2 pin 6 changed from GND to BRAKE_FB",
      "ratio": 19.431372549019606,
      "scope": "Startup continuity only; not runtime cable/current or heatsink monitoring."
    },
    "firmware": {
      "current_ceiling_rms_a": 3.8,
      "global_scaler": 139,
      "initial_irun": 6,
      "initial_current_rms_a": 0.8271367553,
      "brake_preflight_distinct_samples": 3,
      "freshness_ms": 100,
      "bus_window_mv": [
        44000,
        50400
      ],
      "return_to_bus_ratio": [
        0.9,
        1.1
      ],
      "motionWiringVerified": false,
      "pdImageVerified": false,
      "brakeHardwareVerified": false
    }
  },
  "added_components": [
    "D20",
    "R134",
    "R135",
    "R136",
    "C98"
  ],
  "removed_components": [],
  "moved_components": [
    "TP_VMOTOR",
    "TP_PWR_GND"
  ],
  "native_label_changes": [
    "VM and GND follow moved power probes",
    "J2 MOTOR moved clear of added feedback passives"
  ],
  "mounting_holes": "All four existing holes retained unchanged; no unsupported mounting fixture added.",
  "reference_setup": {
    "module": {
      "url": "https://www.analog.com/en/products/pd-1180.html",
      "use": "24/48 V integrated-drive architecture reference only; its 5.5 A/7 Nm rating is not transferred."
    },
    "source_candidate": {
      "model": "Framework Power Adapter 240 W",
      "url": "https://frame.work/products/power-adapter-240w",
      "required_contract": "48 V / 5 A EPR with rated cable",
      "purchased": false,
      "qualified": false
    },
    "motor": "Ordered STEPPERONLINE 34HS31-6004S1, not the 7 Nm ADI module motor",
    "initial_test": {
      "attached_load": "none",
      "max_rpm": 10,
      "acceleration_rpm_per_s": 10,
      "deceleration_rpm_per_s": 10,
      "ambient_c": [
        20,
        25
      ],
      "brake_required": true
    },
    "brake_candidate": {
      "model": "Vishay LPS0300H10R0GB",
      "ohms": 10,
      "continuous_nameplate_w": 300,
      "case_limit_c_at_300w": 85,
      "combined_interface_heatsink_c_per_w_at_281w_50c": 0.1246,
      "qualified": false,
      "final_heatsink_model": null
    }
  },
  "evidence": {
    "calculations": "engineering/power-audit.json",
    "behavioral_simulation": "engineering/power-eco-simulation/results.json",
    "geometry_scope": "engineering/power-eco-geometry.json",
    "brake_sense_branch": "docs/brake-sense-copper-check.json"
  },
  "stock": {
    "checked_at": "2026-10-13T01:37:42.379Z",
    "unique_parts": 84,
    "fitted_parts": 252,
    "status_counts": {
      "available": 31,
      "insufficient": 24,
      "unverified-no-exact-match": 29
    },
    "ordering_approved": false,
    "note": "Missing/null catalog stock remains unverified; the legacy checker labels null stock insufficient. Inventory is not reserved."
  },
  "remaining_gates": [
    "Exact BOM availability and reviewed alternatives",
    "TI full-flash image and readback",
    "Input transient, source/cable contract, eFuse SOA and actual upstream logic draw",
    "Actual motor peak/RMS current, switching loss, capacitor ripple and full thermal soak",
    "Brake diode/cable Q16 VDS transients and repeated brake heating",
    "Actual load, gravity, maximum speed, fastest stop and duty cycle",
    "Runtime brake disconnection remains unmonitored; startup preflight alone is not fault tolerance",
    "Secure mechanical mounting and motor encoder qualification"
  ],
  "validation": {
    "native_DRC_violations": 0,
    "native_unconnected": 0,
    "schematic_parity": 0,
    "schematic_ERC_violations": 0,
    "source_schematic_checks": 173,
    "schematic_sheets": 24,
    "new_via_pad_overlaps": 0,
    "powered_tests": false
  },
  "follow_up": "Historical base ECO record. Current R25/R61/R66 values, request guard and refined screens are in engineering/protection-refinement.json; its geometry proof preserves this ECO."
}