Drogheda/06-Testing-Validation/2026-09-17_Drogheda_HALT-Rig_Thermal-Vibration-Impact_v1.1.md

---
tags: [project-drogheda, testing, halt, environmental, hbox, rig]
project: Project Drogheda
author: Helgen CTO
date: 2026-09-17
status: APPROVED FOR BUILD
version: 1.1
supersedes: 2026-09-17_Drogheda_HALT-Rig_Thermal-Vibration-Impact_v1.0.md
---

# DIY Environmental Test Rig — Thermal + Vibration + Impact for HBOX

!!! warning "Designators from before 22-Oct (T43)"
    This document keeps the designators the board had on its date. Since 22-Oct (T43) the V5.6, V5.7 and v6 carry new ones, and several old names now belong to another part: on the v6, U6 is now the A7670SA modem (was U19) and the LTC4040 is U17 (was U6). To read it against today's board, use the [old → new table](https://drogheda.helgen.online/hardware/designadores-t43-22oct/#8-tablas-viejo-nuevo) (in Spanish); parts already gone by 22-Oct are not in it.

## 🔒 Decisions locked (Leo, 17-Sep)

| # | Decision | Consequence |
|---|---|---|
| D1 | **Chamber designed for 75 °C, campaigns run at 60 °C** | 75 mm rockwool (not 50), 900 W heaters (not 600), 100 °C cutout (not 85), silicone-insulated internal wiring throughout |
| D2 | **Full vibration drive: motovibrador + VFD** | 3-ph 0.18–0.25 kW with adjustable counterweights, 0.75 kW VFD 1-ph→3-ph. Banded sweeps are repeatable run-to-run |
| D3 | **Shop time is available** | Build starts now, in parallel with the field-log firmware. 4-week plan in §9 |
| D4 | **Architecture changed from v1.0 — see §3** | D1 forced it. The hot box is now **fixed**; a light fixture moves *inside* it |

---

## ⚠ What changed from v1.0, and why it matters

v1.0 had the whole hot box riding on the shaker. Running the 75 mm insulation
required by **D1** through that geometry gives:

```
rockwool shell (0.55³ − 0.40³ = 102 L @ 100 kg/m³)   10.2 kg
3 mm alu liner, 0.4 m cube                            7.8 kg
12 mm alu platen 400×400                              5.2 kg
outer skin                                            8.5 kg
2 DUTs + heaters + fixture                            8.0 kg
                                          TOTAL      39.7 kg   ← was 16 kg
```

**40 kg of moving mass breaks the mechanical stage.** The shock pads would need
3.24 MN/m (810 kN/m each across four), and the eccentric would need ~2.5× the
counterweight to reach the same g. We would be spending the entire vibration
budget shaking insulation.

**The fix — decouple.** Hot box fixed and heavy; a **light aluminium fixture
moves inside it**, driven from below by a rod through a silicone bellows in the
chamber floor. The motovibrador, the VFD and every bearing stay outside in cool
air, which is where they belong anyway.

```
              new moving mass
   15 mm alu fixture plate 300×300     3.6 kg
   20 mm steel drive rod, 350 mm       0.9 kg
   2 HBOX DUTs + brackets + accel      5.8 kg
                         TOTAL        10.3 kg   ← better than v1.0's 16 kg
```

Every mechanical number in §5 and §6 is smaller and cheaper as a result. This
change makes the rig *more* capable, not less. It also removes the v1.0 problems
of mains heaters and a PID on a shaking platform.

---

## 1. What we are actually trying to catch

Unchanged from v1.0. Summary: most of our known HBOX failures are **thermal**,
not mechanical (LTC4040 hot-pause at ≈ +42 °C with `RNTB` = 10 k; the 10-Ago
modem boot-loop; the June nested-cabinet heat trap). Vibration and impact are
insurance for the 250-unit rollout, where a 1 % mechanical failure rate is
two or three truck rolls to Veracruz.

Consequence for the build order: **the chamber is useful on day one and is built
first.** The mechanical stage follows in week 2–3.

---

## 2. Step zero: measure the crane, don't guess it

**Still the highest-value action in this document, and it costs nothing.**

EinarBoard v6 carries **U26 = SC7A20TR** (LIS3DH-compatible, I²C 0x18,
INT1 → PB9). The `$PHLG` vibration fields are already an open firmware item in
the v6 brief. Finish that item, flash one unit, mount it on a live crane at
ICAVE for 5–7 working days, log raw XYZ at 400 Hz ODR in bursts (10 s every
5 min, plus a triggered burst on INT1 over threshold).

That gives us the real PSD, the real shock spectrum, the real event rate per
shift, and one defensible sentence for the client report:

> *"The rig reproduces the 95th-percentile measured field environment at ICAVE,
> with an acceleration factor of N."*

That is worth more to Hutchison than "we ran IEC 60068-2-6."

**Reference severities, for calibration of expectations only:**

- **IEC 60068-2-6** (Fc, sine sweep) — generic industrial: a constant-displacement
  leg then a constant-acceleration leg, 1 oct/min. Toradex, e.g., runs
  10–55 Hz @ 0.54 mm and 10–300 Hz @ 39 m·s⁻².
- **IEC 61373 Cat 1 Class B** — railway, equipment in a case on the car body.
  Closest analogue in spirit: low-level random 5–150 Hz + 5 h/axis long-life.
- **IEC 60068-2-27** (Ea, shock) — half-sine 15 g/11 ms, 30 g/18 ms,
  30 g/11 ms, 50 g/20 ms; 200–1000 shocks per direction, 3 axes.

**Fallback if the field log slips:** build to **5–80 Hz, peaks to 2 g**, plus
**15 g / 11 ms half-sine**. Those are the numbers sized below.

---

## 3. Architecture (revised — D4)

```
   ┌──────────────────────────────────────────────┐
   │ FIXED HOT BOX — 400×400×400 useful           │
   │ 75 mm rockwool · 3 mm alu liner · 900 W PTC  │
   │                                              │
   │      ┌──────────┐      ┌──────────┐          │
   │      │  HBOX A  │      │  HBOX B  │          │  DUTs on the SAME
   │      └────┬─────┘      └────┬─────┘          │  bracket the crane uses
   │     ╔═════╧═════════════════╧═════╗          │
   │     ║ 15 mm alu FIXTURE 300×300   ║ ← ADXL355│  MOVING: 10.3 kg
   │     ╚═══════════╤═════════════════╝          │
   │   [spring]      │       [spring]             │  4× 2.5 N/mm, fn ≈ 5 Hz
   │═════════════════╪══════════════════════════════│ chamber floor
   │                 ▓ ← silicone bellows, 50 mm bore
   └─────────────────╪────────────────────────────┘
                     │ 20 mm drive rod
              ┌──────┴──────┐
              │ ECCENTRIC   │  motovibrador + VFD, OUTSIDE, in cool air
              │  0.18 kW    │  adjustable counterweights
              └─────────────┘
              steel base frame, floor-anchored
```

**Vibration mode:** fixture floats on 4 soft springs (fn ≈ 5 Hz); the rod
transmits the eccentric's force. Everything hot is stationary; everything
rotating is cool.

**Shock mode:** springs removed; the rod lifts the fixture a set height on two
guide shafts and releases it onto elastomer pucks bolted to the chamber floor.
Same fixture, same DUT mounting, same accelerometer. **Mode change ≈ 20 min.**

**Axes:** rotate the DUT in its bracket, not the rig. Three orthogonal
orientations.

**Do not** attempt vibration and shock simultaneously — the pad stiffness
requirements are in direct conflict (2.5 N/mm vs 210 kN/m, a factor of ~80).

### Service penetrations

- Drive rod: 50 mm bore, **silicone bellows boot** (200 °C rated, trivially
  available). Conduction through the bellows wall is <0.1 W; budget 5–10 W for
  annulus convection. Irrelevant against 900 W.
- DUT harness (24 V, RS-232/RS-485, thermocouples, accelerometer): silicone
  gland plate on the **rear** face, with a slack service loop inside so the
  moving fixture doesn't tension the cables. **This is the #1 thing that breaks
  on rigs like this** — give it 150 mm of slack and anchor both ends.

---

## 4. Thermal stage — 75 °C capable, 60 °C operating

### Sizing (D1)

Steady-state conduction, 75 mm rockwool (k ≈ 0.040 W·m⁻¹·K⁻¹), 0.40 m inner /
0.55 m outer, mean area 1.354 m²:

| Setpoint | Ambient | Conduction | ×3 for leakage, bridges, penetrations |
|---|---|---|---|
| 60 °C | 15 °C | 32.5 W | **97 W** |
| 75 °C | 15 °C | 43.3 W | **130 W** |
| 75 °C | 25 °C | 36.1 W | 108 W |

Note the elegance of D1: 75 mm of insulation at 75 °C loses the same as 50 mm at
60 °C. The extra insulation pays for the extra ΔT exactly.

**Pull-up dominates the sizing.** 10 kg alu fixture + hardware + 5 kg DUT:

| Target | Energy | @ 600 W | @ **900 W** | @ 1200 W |
|---|---|---|---|---|
| 60 °C (ΔT 35 K) | 455 kJ | 14 min | **9 min** | 7 min |
| 75 °C (ΔT 50 K) | 650 kJ | 20 min | **13 min** | 10 min |

**Specify 900 W** = 3 × 300 W PTC fan-heater modules, PID-controlled together.
The air charge is 3.2 kJ — negligible against 650 kJ of metal, so don't bother
sizing for it.

PTC elements remain the right choice: self-limiting, sealed modules with the fan
integrated, cannot run away if the fan stops.

### Control and safety — two independent layers, non-negotiable

1. **Control:** REX-C100 PID → SSR-40DA → the three heaters. Type-K thermocouple
   in the **return air stream**, not touching a DUT.
2. **Independent over-temperature cutout: KSD301 100 °C NC thermostat in series
   with the coil of a mechanical contactor** feeding the heaters.
   The dominant SSR failure mode is **shorted on**, and the PID then has zero
   authority. The contactor is the only thing between a stuck SSR and a fire
   during an overnight soak. **Prove it by test at commissioning** — jumper the
   SSR closed deliberately and confirm the contactor drops out.
3. 10 A breaker, metal control enclosure, PE bonded to the alu liner and to the
   steel frame.

### D1 material consequences

- **All internal wiring silicone-insulated**, not PVC. PVC at 75 °C in still air
  next to a 300 W element will go brittle and then conductive.
- Door seal: **silicone** oven gasket (rated 200 °C+), not EPDM or foam tape.
- **Rockwool, not EPS/XPS/polyiso.** EPS is rated ~75 °C — i.e. exactly at our
  design point — and will soften and outgas. Rockwool is non-combustible and
  costs the same.
- 3 mm aluminium liner as both fire barrier and fibre containment.
- The HBOX ASA case softens ~95–100 °C, so 75 °C is safe for the enclosure
  itself. The cells are the constraint, not the plastic.

### Independent temperature logging

Three spare type-K probes (one per DUT surface, one in air) → 4-channel SD/USB
logger, **outside** the box. The report needs a measured trace, not "the PID
display said 60."

### 🔴 Battery hazard

The HBOX contains a lithium pack. 60 °C ambient + self-heating + LTE TX bursts
puts cells above their charge window, and per `Battery-Chemistry-HighTemp v1.0`
the LTC4040 already hot-pauses at ≈ +42 °C with `RNTB` = 10 k.

- First soaks: pack fitted, **charger inhibited**, thermocouple on the pack.
- **Never leave the first soak of a new configuration unattended.**
- Class-D extinguisher or dry sand + welding blanket at the rig. **Not CO₂.**
- **Do not run the 75 °C capability with a Li-ion pack installed.** 75 °C is for
  bare-board and enclosure work, or for LFP once that decision lands.
- Useful side effect: this chamber is the cheapest way to prove the
  `RNTB` → 5.6 k + high-temp LFP decision before it enters the 30-unit BOM.

---

## 5. Vibration stage (re-sized for M = 10.3 kg)

### Suspension

| fn | k total | per spring (×4) | static deflection |
|---|---|---|---|
| 4 Hz | 6.51 kN/m | 1.63 N/mm | 15.5 mm |
| **5 Hz** | **10.17 kN/m** | **2.54 N/mm** | **9.9 mm** |
| 6 Hz | 14.65 kN/m | 3.66 N/mm | 6.9 mm |

**Specify 4 × 2.5 N/mm compression springs**, fn ≈ 5 Hz, ~10 mm static sag.
Band A starts near this resonance — **do not dwell at 5–7 Hz** until the
accelerometer trace has been watched.

### The honest limitation (unchanged in principle, better in magnitude)

A fixed eccentric on a soft-mounted mass gives **constant displacement**, so
acceleration rises as **f²**:

| m_e·e | x peak | 5 Hz | 10 Hz | 20 Hz | 30 Hz | 45 Hz | 60 Hz | 80 Hz |
|---|---|---|---|---|---|---|---|---|
| 1 g·m | 0.10 mm | 0.01 | 0.04 | 0.16 | 0.35 | 0.79 | 1.41 | 2.50 |
| 2 g·m | 0.19 mm | 0.02 | 0.08 | 0.31 | 0.70 | 1.58 | 2.81 | 5.00 |
| 5 g·m | 0.49 mm | 0.05 | 0.20 | 0.78 | 1.76 | 3.95 | 7.03 | 12.5 |
| 10 g·m | 0.97 mm | 0.10 | 0.39 | 1.56 | 3.51 | 7.91 | 14.1 | 25.0 |
| 20 g·m | 1.94 mm | 0.20 | 0.78 | 3.12 | 7.03 | 15.8 | 28.1 | 50.0 |

(values in g)

You cannot hold a flat level across 5–80 Hz with one weight setting. Anyone
claiming an eccentric rig "runs IEC 60068-2-6" either has closed-loop amplitude
control or is not measuring.

### Banded sweep plan — **this is the operating procedure**

| Band | Freq | Motor RPM | Counterweight m_e·e | as mass @ 50 mm | x peak | a at bottom → top |
|---|---|---|---|---|---|---|
| **A** | 5–15 Hz | 300–900 | 12.5 g·m | 250 g | 1.22 mm | 0.12 → 1.10 g |
| **B** | 15–40 Hz | 900–2400 | 3.2 g·m | 64 g | 0.31 mm | 0.28 → 2.00 g |
| **C** | 40–80 Hz | 2400–4800 | 1.4 g·m | 28 g | 0.14 mm | 0.88 → 3.50 g |

Sweep each band at 1 octave/min, N cycles, in Z first (crane deck is dominantly
vertical), then X, then Y. **The accelerometer logs what actually happened** and
the report states measured levels per band. That is honest and still perfectly
good at finding cracked joints.

> ⚠ **Band C overspeeds a 60 Hz motor to 80 Hz on the VFD.** Check the
> motovibrador's rated maximum centrifugal force and bearing speed first, and
> de-rate the weights accordingly — bearing load scales as f² too. If the
> datasheet forbids it, stop band C at 60 Hz and add the BLDC option (§5.3).

### 5.3 Optional reach above 80 Hz (~$1,200 MXN)

RC outrunner BLDC + 80 A ESC + servo tester, eccentric disc on the shaft, spins
past 10 000 rpm. Crude, but it is the only cheap way to excite **PCB-level
resonances (typically 150–300 Hz)** — which is where L22, U25 and the 100 µF/50 V
can would crack if they are going to. Worth adding if the field log shows
meaningful energy above 80 Hz, or if a post-test teardown finds joint damage.

### 5.4 Phase 2 (~$6k MXN) — the woofer shaker

15" pro woofer, voice coil coupled to a light fixture, class-D amp from a PC
sound card, accelerometer as the control sensor → genuine **closed-loop swept
sine and random, 20–200 Hz**. ~100 N of force, so ~2 g on a 5 kg bare-PCBA
fixture. The only sub-$10k route to a truly controlled profile. Not needed for
v1; revisit after the first campaign.

---

## 6. Impact / shock stage (re-sized for M = 10.3 kg)

Guided drop inside the chamber. The fixture is lifted on the drive rod plus two
guide shafts and released onto elastomer pucks on the chamber floor. Peak g and
duration are set by drop height and puck stiffness, and **both are measured**.

| Severity | Δv | Drop, 30 % rebound | Drop, 0 % rebound | Pad k total | per pad (×4) |
|---|---|---|---|---|---|
| 3 g / 30 ms | 0.56 m/s | 10 mm | 16 mm | 0.113 MN/m | 28 kN/m |
| **15 g / 11 ms** | **1.03 m/s** | **32 mm** | **54 mm** | **0.841 MN/m** | **210 kN/m** |
| 30 g / 11 ms | 2.06 m/s | 128 mm | 216 mm | 0.841 MN/m | 210 kN/m |
| 30 g / 18 ms | 3.37 m/s | 343 mm | 580 mm | 0.314 MN/m | 79 kN/m |

Everything to 30 g / 11 ms fits inside 250 mm of shaft travel, which fits inside
the 400 mm chamber. 30 g / 18 ms does not — that one needs the fixture outside
the box, cold. Accept that limit.

**Puck starting sizes** for 15 g / 11 ms, from k = E·A/L, 25 mm thick:
Shore 60A ≈ 41 mm dia, Shore 70A ≈ 33 mm dia.

> ⚠ k = E·A/L **under-estimates** real rubber in compression: a constrained
> squat puck is stiffened by its shape factor, often 2–4×. The pucks you
> actually need will be **smaller or softer** than the table says. Buy an
> assortment (Shore 60A and 70A, 20/25/30/40/50 mm) and tune against the
> accelerometer trace. Budget one afternoon.

Lift by hand with a lever and a detent for v1. Motorise with a cam later only if
we want 1000-shock endurance runs.

---

## 7. Instrumentation

| What | Sensor | Notes |
|---|---|---|
| Rig reference vibration | **ADXL355** (±8 g, 20-bit, SPI) | Bolted to the fixture plate. This is the sensor the report quotes |
| Shock peaks | **ADXL1002** (±50 g, 11 kHz BW, analog) | The ADXL355 will clip and alias on a 15 g / 11 ms pulse |
| DUT-internal vibration | **U26 SC7A20**, already on the v6 board | Free. Correlating it against the field log **is** the validation of the rig |
| Temperature | 3 × type-K + the DUT's own `tair` (SHT40), `tntc`, `tbat` (TMP102) | Already in `$PHLG` |
| DUT health | `$PHLG` over RS-232/RS-485, logged continuously | Pass/fail evidence |

Logger: Teensy 4.0 or Pi Pico → SD, ≥2 kHz on the shock channel, **outside the
hot box**. Sensor cables through the rear gland plate with the service loop.

**Define pass/fail on `$PHLG` before the first run, not after.** Suggested:
no GNSS fix loss > N s · no modem re-registration · no watchdog reset ·
no `cflt` that fails to clear · C/N₀ drift within X dB.

---

## 8. BOM (MXN, Sep-2026 street prices, ±25 %) — D1 + D2 configuration

### Thermal stage — 900 W, 75 °C capable

| Item | Qty | Est. |
|---|---|---|
| Aluminium sheet 3 mm, liner + door (0.4 m cube) | — | 2,000 |
| Rockwool board **75 mm**, ~2.5 m² | — | 1,000 |
| Outer skin: 18 mm plywood or 1.2 mm steel, frame | — | 900 |
| PTC fan-heater module 220 V **300 W** | **3** | 1,050 |
| High-temp circulation fan, metal blade | 1 | 400 |
| PID kit: REX-C100 + SSR-40DA + type-K probe | 1 | 450 |
| **KSD301 100 °C NC cutout + mechanical contactor** + 10 A breaker | 1 | 550 |
| 3 × spare type-K probes + 4-ch SD/USB temp logger | 1 | 700 |
| **Silicone-insulated wire** (internal), silicone glands, gland plate | — | 600 |
| **Silicone oven gasket**, piano hinge, over-centre latches | — | 500 |
| **Silicone bellows boot, 50 mm bore** + floor flange | 1 | 450 |
| Control enclosure, IEC inlet, indicators, E-stop | — | 800 |
| **Subtotal** | | **9,800** |

### Vibration stage (D2 — full)

| Item | Qty | Est. |
|---|---|---|
| **Motovibrador 3-ph 0.18–0.25 kW, adjustable counterweights** | 1 | 3,500 |
| **VFD 0.75 kW, 220 V 1-ph in → 3-ph out** | 1 | 1,900 |
| Aluminium fixture plate **15 mm, 300×300** | 1 | 1,400 |
| Drive rod 20 mm steel + couplings + rod-end bearing | — | 900 |
| Compression springs **2.5 N/mm** + guide cups | 4 | 500 |
| Steel base frame (2" PTR, welded, floor-anchored) | 1 | 1,600 |
| Guarding: steel mesh + polycarbonate window, E-stop | 1 | 1,200 |
| Fasteners, Loctite 243, DUT brackets (crane-identical) | — | 700 |
| **Subtotal** | | **11,700** |

### Impact stage

| Item | Qty | Est. |
|---|---|---|
| Guide shaft 16 mm × 300 mm + SC16UU bearings | 2 + 4 | 900 |
| Lift lever, detent, release latch, shaft supports | 1 | 900 |
| Rubber puck assortment, Shore 60A/70A, 20/25/30/40/50 mm | — | 600 |
| **Subtotal** | | **2,400** |

### Instrumentation

| Item | Qty | Est. |
|---|---|---|
| ADXL355 breakout | 1 | 1,100 |
| ADXL1002 breakout (shock channel) | 1 | 700 |
| Teensy 4.0 + SD + protoboard + silicone wiring | 1 | 900 |
| **Subtotal** | | **2,700** |

### Total

| | MXN |
|---|---|
| Thermal | 9,800 |
| **Safety (was missing a cost line in v1.0 — corrected)** | **1,100** |
| Vibration | 11,700 |
| Impact | 2,400 |
| Instrumentation | 2,700 |
| Subtotal | **27,700** |
| Contingency 15 % | 4,155 |
| **TOTAL** | **≈ 31,855** |

**Authoritative costing is now the BOM workbook**, not this table:
`2026-09-17_Drogheda_HALT-Rig_BOM_v1.0.xlsx`. The v1.0 draft understated the
thermal stage by $400 (arithmetic) and carried the safety kit at zero.

**$1,855 above the $30k top of the agreed band.** Three ways to come back inside:

- Drop the ADXL1002 and accept clipped shock peaks on the ADXL355 (−700). Not
  recommended; the shock channel is the one measurement we cannot fake.
- Steel fixture plate instead of aluminium (−700). Adds 6 kg of moving mass and
  undoes part of §3. **Not recommended.**
- Build the thermal stage now and the mechanical stage in October from the next
  budget cycle. **This is the recommended way to stage it** — the chamber is
  useful alone and is the part that addresses our actual known failures.

---

## 9. Build sequence (shop time available — D3)

| Week | Shop | Firmware / field | Gate |
|---|---|---|---|
| **1** (22–26 Sep) | Cut and fold the liner, build the shell, mount heaters + circulation fan, wire PID + SSR + **contactor and cutout** | Finish `$PHLG` vibration fields + SC7A20 driver; flash one unit | **G1:** empty chamber holds 60.0 ± 1.0 °C for 4 h; **cutout proven by deliberate SSR-short test** |
| **2** (29 Sep–3 Oct) | Base frame, fixture plate, drive rod, bellows, springs, guarding. *(Note: ICAVE/Lázaro shipment lands this week — expect contention)* | Unit mounted on a live crane at ICAVE; logging | **G2:** bare fixture sweeps 5–80 Hz, accelerometer trace logged and sane; no frame resonance in band |
| **3** (6–10 Oct) | Drop conversion: guide shafts, lift lever, puck tuning | Pull the field log; derive PSD + shock spectrum; **freeze the rig target profile** | **G3:** three consecutive pulses within ±20 % of target; rig profile signed off |
| **4** (13–17 Oct) | Run campaign v1 (§10) | — | **G4:** report |

**Commissioning runs that must not be skipped:**

- **Empty chamber, 4 h at 60 °C** — map the hot spots with the three spare
  probes before a DUT confuses the picture. Then repeat once at 75 °C.
- **Bare fixture sweep, all three bands** — characterise the rig's own
  resonances. If the base frame or the guarding rings at 30 Hz, you will spend
  the campaign chasing it.
- **Deliberate SSR-short test** — see G1. Do it with nothing in the box.

---

## 10. Campaign v1

**DUT-A gets everything. DUT-B is the control and gets only the thermal soak** —
so a failure tells us heat or mechanics, not both. Both fully instrumented,
powered and transmitting throughout.

1. **Baseline** — 1 h at 25 °C, full `$PHLG`, GNSS + NTRIP + LTE. Record C/N₀,
   fix type, modem RSSI, `tbat`, `cflt`. This is the reference.
2. **Thermal soak** — ramp to 60 °C over 30 min, hold 8 h with LTE TX active;
   cool to ambient; ×3 cycles. Watch: charge stall, modem re-registration
   storms, fan policy, watchdog resets, C/N₀ drift.
3. **Hot vibration** — at 60 °C, bands A/B/C, 10 sweep cycles each, Z then X
   then Y.
4. **Hot shock** — still at 60 °C, 100 half-sine pulses per direction ×
   3 orientations, at the measured field severity (fallback 15 g / 11 ms).
5. **Post-test** — repeat step 1 verbatim and **diff against the baseline**.
   Then open both units: visual inspection of L22, U25, the 100 µF/50 V can,
   the GX16 entry and every connector; torque-check every screw; re-seat and
   re-measure both U.FL pigtails.

The diff in step 5 is the deliverable. *"Nothing visibly broke"* is not a result.
*"C/N₀ fell 2.1 dB and never recovered"* is.

---

## 11. What this rig will NOT give you

State this plainly in any client-facing use of the results.

- **No traceability** — no calibrated accelerometer, no accredited lab, no
  certificate. Self-declared measurements with a commercial MEMS reference.
- **No closed-loop profile control** — a measured, displacement-limited banded
  sweep, not a controlled constant-g or PSD-shaped profile.
- **Single-axis at a time**, not simultaneous triaxial.
- **No cold, no humidity, no salt fog.** Ports are humid and saline; for us that
  is probably a *more* relevant missing test than cold. Consider a salt-fog
  add-on after this rig proves out.
- **Not a substitute for certification** if a client demands IEC/EN compliance.
  It *is* a legitimate pre-screen that makes a paid lab run far more likely to
  pass first time — which is where it saves real money.

---

## 12. Remaining open items

1. **Battery-in vs battery-out for campaign v1.** Recommendation: in, charger
   inhibited, pack instrumented. Revisit when the LFP decision lands.
   **Hard rule: no Li-ion pack in the box above 60 °C.**
2. **Who owns the rig?** It needs a named owner for calibration checks (monthly
   accelerometer cross-check, thermocouple ice-point check) or it will drift and
   quietly stop being trustworthy.
3. **Week-2 shop contention** with the ICAVE/Lázaro shipment. Flagged, not
   resolved.
4. **BLDC option (§5.3)** — decide after the field log shows whether there is
   energy above 80 Hz.

---

## References

- IEC 60068-2-6 — Test Fc, sinusoidal vibration
- IEC 60068-2-27 — Test Ea, mechanical shock (half-sine severities)
- IEC 60068-2-64 — Test Fh, broadband random vibration
- IEC 61373 — Railway rolling stock, shock and vibration, Cat 1 Class B
- `03-Architecture-Hardware/2026-09-09_Drogheda_Battery-Chemistry-HighTemp_v1.0.md`
- `03-Architecture-Hardware/2026-08-24_Drogheda_EinarBoard-v6_GNSS-4G-Integration_Design-Brief_v1.0.md`
- `06-Testing-Validation/RCA-2026-06-field-failures.md`
- `06-Testing-Validation/2026-08-18_Drogheda_FW-v3.0.3_Fan-Policy_Bench-Test_v1.0.md`
- Companion: `2026-09-17_Drogheda_HALT-Rig_BOM_v1.0.xlsx` (**authoritative BOM** — buy from this)
- Companion: `2026-09-17_Drogheda_HALT-Rig_Lista-Compras_ES_v1.0.md` (narrative purchasing notes)