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Automatic System Characterization

Once the XREG-010 is wired, its Vessel Info is filled in, and you've set the commonly-adjusted settings for your bank and alternator, run Automatic System Characterization once. It measures how your alternator, engine, and battery bank actually respond, sets the control-loop gains from those measurements, measures the current ripple your alternator produces so the over-current protection can be sized to it, and includes a stress test that deliberately fires the over-voltage protection and grades the recovery — instead of leaving you to guess at gains and thresholds.

The wizard launches itself the first time you save Vessel Info on a new regulator. To get back to it later — to resume, re-run steps, or restart it manually — go to Setup → Alternator → Commissioning, the first tab in the Alternator row. The walkthrough is ten steps, most under a minute each; your only job is to hold the engine at the speed each step asks for.

Why it's worth doing

The regulator ships with safe, conservative defaults, but the right control-loop gains and over-current thresholds depend on your specific alternator, belt, and engine. Characterization tunes the gains to your installation so the regulator reacts quickly without overshooting, and measures the ripple you size the over-current threshold against so it sits at the right level. That last point matters even when you hold a fixed voltage target, and especially on large battery banks, where the voltage barely moves as current climbs: voltage-based protection has little to react to, so a correctly-sized over-current threshold is what catches a runaway.

Before you start

  • Use a laptop or tablet if you can. Setup and Commissioning works on a phone, but it's a worse UX on a small screen.
  • The engine can run and the alternator is producing current.
  • The battery has charging headroom — roughly the 20–70% state-of-charge range is ideal. Characterization has to hold a current while it measures, and a full bank won't allow that.
  • No other tuning test is running.
  • BMS charge-limit follow is off. If you turned on Follow BMS Charge Limits (Setup → Integrations → Charge-Limit Follow), switch it off before you start — characterization has to own the battery, and it ignores external limits while the wizard runs.
  • House loads are steady — avoid switching large loads on or off mid-run.
  • You can hold the throttle steady when asked, snap it briskly once for the Stress Test, and move it slowly up and down on cue for Charge Health Calibration.

You never touch the field

The regulator drives the field itself throughout. Your only job is to set engine speed when the routine prompts you. Your current settings are saved before anything changes, so you can Abort and revert all at any point and everything reverts to exactly how it was.

Setup screens before the wizard

A few short screens come before the wizard itself, on every pass: Before You Start (the run-conditions reminder above), Prerequisites (which sensor measures what, the alternator temperature source and limit, and the battery shunt), and Charge Rate Limits (the High and Low current-per-RPM tables — commissioning normally runs in Low, and when it finishes the regulator offers to switch you to High). On a first install only, Tachometer Calibration (make the reported RPM agree with your tachometer, since every later step prompts you for engine speeds) follows Charge Rate Limits, and Recommend Initial Charging Settings, the state-of-charge estimate, and the maintenance-restart notice come between Prerequisites and Charge Rate Limits. Each screen is covered in full in Initial Settings.

The ten steps

Each step shows its instructions on arrival, runs when you press its button, then shows you what it measured and proposes — nothing is written until you accept. This is the first screen of the walkthrough:

Commissioning wizard, first screen (Prep)

  1. Prep — checks the preconditions (engine running, charging headroom) and snapshots every setting the wizard might touch, so Abort can restore it all.
  2. Field curve — sweeps the field drive over its full range with no feedback control (open loop), mapping drive → amps and finding where the alternator stops giving more current (the saturation knee).
  3. Current Control Autotuning — runs a small open-loop sine sweep to measure the field coil's electrical lag, then proposes the current-loop gains and filter time constants.
  4. Verify Current Control — drives the newly-tuned loop through a closed-loop sweep from slow to fast, confirming it tracks without ringing and finding the speed it can actually follow (the bandwidth).
  5. Disturbances — a throttle-driven game maps the current ripple your engine, belt, and alternator actually produce at each engine speed, for the alternator over-current detector.
  6. Fault Threshold Autotuning — parks the over-current trip lines a safety margin above that measured ripple, and sets the voltage-loop damper's tolerance the same way.
  7. Voltage Control Autotuning — pulses the charge current and measures how stiff the battery is (how many millivolts it moves per amp) at the voltage loop's own reaction timescale, then proposes the voltage-loop gains.
  8. Keep-Alive Floor & Field Decay — at three held speeds with the engine fully warm, finds the lowest field drive that produces any output (the tachometer keep-alive floor) and times how fast alternator output dies after a protection cut — the number the over-voltage response uses to decide how long to hold the field down.
  9. Stress Test — deliberately provokes the over-voltage protection with a throttle snap and grades the recovery. The graded exam; it has its own page. It writes no settings, so it is optional — skipping it still leaves the device Commissioned.
  10. Charge Health Calibration — you hold the engine near three-quarters of maximum working RPM while the field is set, then make three slow throttle passes at a fixed field: down to idle, back up, and down again. It measures how far alternator output runs ahead of engine speed, which the charging-system health tracker needs before it can grade anything recorded under way. It needs a battery that will still accept current, so it is optional too.

Protections during the tests

The measurement steps that drive the field directly run with the current-based protections paused, but the fast over-voltage hard shutdown stays live the whole time — which steps fall in which case is on the Full Explanation page.

Pausing, resuming, and re-running steps

Closing the wizard with the X pauses it — each completed step's result is already saved, and the Commissioning tab shows exactly where things stand. Whichever way you come back, Continue commissioning runs the Before You Start, Prerequisites and Charge Rate Limits screens again, opens the wizard at Prep (the other-charging-sources check and the settings restore point happen on every pass) and then goes straight to the first ticked step:

Commissioning tab mid-run: per-step checkboxes, DONE marks, and a RESUME pointer

  • The checkbox on each row selects it for the next pass, so you can run just the steps you want. Steps feed each other, though: re-running the Field curve re-runs the current-loop and voltage-loop tuning built on it, and re-running Disturbances re-runs Fault Threshold Autotuning. Ticking a step automatically ticks the steps it feeds. The Stress Test is the exception: a re-tune upstream of it clears its tick mark, because the verdict no longer describes the loop you now have — but it is not added back to the plan automatically. It writes nothing and is optional, so re-selecting it is left to you. Keep-Alive Floor & Field Decay and Charge Health Calibration are independent — nothing feeds either one. Unticking a step also unticks the steps that feed it, so a plan can never leave a fed step stale.
  • Skip for now sets a step aside but keeps it flagged as outstanding; Mark done manually counts it as complete without a measurement, and the checklist marks it MANUAL so that stays honest.
  • Stop — keep finished steps (inside the wizard) ends the session for now. Every finished step is kept; only the step in progress is discarded, and it runs again when you continue. The Commissioning tab comes back with the remaining steps ticked.
  • Abort and revert all (inside the wizard) puts every setting back to how it was before the run started and discards the steps finished during it — a device that was commissioned before the run is commissioned again. Clear and restart commissioning on the tab issues the same revert and then starts the walkthrough over from the top. On a device that has already finished commissioning there is nothing left to revert to — the snapshot was discarded when you finished — so the tune it is running becomes the starting point for the new run, and the commissioned mark is cleared.
  • A reboot only loses the step that was actually mid-measurement; completed steps keep their DONE marks and the wizard resumes at the first unfinished one.

When it finishes

The device is marked Commissioned once the first eight steps are done. The Stress Test and Charge Health Calibration are the exceptions: skipping either one neither blocks the badge nor keeps the "not yet commissioned" reminder alive. Each still gets its own tick mark, and the Stress Test still goes stale if you later re-run a step it depends on. If you ran in the Low charge-rate limits, the regulator then offers to switch you to High so the alternator delivers its full output in normal use. You can re-run any step — or the whole walkthrough — at any time from the Commissioning tab, and the regulator will suggest re-running characterization if you later change Vessel Info settings that affect it.

Watching the over-current detector

During normal running, the iExcess over-current detector (Group 3, on alternator current — one detector pair covering both the voltage-holding phase and the current-limited phase) shows a live chart under Setup → Alternator → Protections. It plots the time-averaged amount the measured current sits above what the regulator is commanding, against the threshold that would trip it. A clean run keeps the current trace well under the threshold line; a real over-current crosses it and draws a marker. Use it to confirm the thresholds you set are sitting comfortably clear of normal operation.

See Safeties & Protections for how all the protection layers work together.

If you skip it

The regulator still runs on its conservative defaults — it's safe to use as-shipped. But the control loop may be slower to settle than it needs to be, and the over-current threshold is a generic value rather than one matched to your alternator. Running characterization once is the recommended setup step after wiring and initial settings.

Cross-references

  • Initial Settings — Previous step; fill these in first.
  • Full Explanation — What each step measures and how the numbers are derived. The wizard links to it per step.
  • Stress Test — Detailed page on the graded exam and how its verdict is reached.
  • Operating Modes & Power — Next step; how the regulator behaves once it's running.
  • Safeties & Protections — How the over-voltage, over-current, temperature, and other protection layers work.