From d7c23cce1978771f3237e98a89eb55ecbab7cb51 Mon Sep 17 00:00:00 2001 From: ScottW514 Date: Mon, 17 Aug 2026 21:52:15 -0400 Subject: [PATCH] A longer minimum pulse is worse: the gap is what decides striking min_ticks 6 broke 5 percent striking - seven current segments where 3 gave eight, on a 36.5 s fire window against 41.4 s for eight rungs. Below the minimum the model emits min ticks every min/on periods, so the interval between pulses is min_ticks x tick / density and the base period cancels, which is also why periods 10, 20 and 40 gave identical results earlier. At 5 percent that is 2.26 ms at min 3, which struck, against 4.51 ms at 6, which did not: doubling the minimum doubles the gap as well as the pulse, and the discharge is re-struck each pulse. min 3 sits at the factory's own operating point - its 6.5 percent engrave jobs place 100 us pulses 1.54 ms apart against 1.64 ms for min 3 at that density - and 6 is outside anything the factory does. The bench is back at 3. Measured band for this tube: strikes from ~5 percent density, marks from ~10 percent at F300. That closes the pulse-structure route to a usable 1 percent, since the interval grows as 1/density and 1 percent implies an 11 ms gap. The low end is a scaling problem, and $35 is the control. --- docs/BRINGUP.md | 20 ++++++++++++++++++++ docs/CAMPAIGN-LOG.md | 42 +++++++++++++++++++++++++++++++++--------- 2 files changed, 53 insertions(+), 9 deletions(-) diff --git a/docs/BRINGUP.md b/docs/BRINGUP.md index af0d3cf..f6a199d 100644 --- a/docs/BRINGUP.md +++ b/docs/BRINGUP.md @@ -724,6 +724,19 @@ not a release. corner instead of the ~7.7× it would rise with no compensation. On the UI scale, PP 1→100 is linear in density (~0.006 per unit, intercept ~0.189) and Full Power sits off that line, where PP ~134 would land. +- **Density dose limits** (measured on five ladders, `dladder`): under the + FIRE-density model the interval between pulses at a level below the + minimum is `min_ticks x tick / density` - **the base period cancels**, + which is why periods 10, 20 and 40 gave identical results. The tube + **strikes down to ~5 % density at a 2.26 ms interval** (`min_ticks` 3, + 106 us pulses) and **fails to strike at 4.51 ms** (`min_ticks` 6, 213 us): + lengthening the pulse at fixed density lengthens the gap in proportion, + and the gap is what kills re-striking. It **marks from ~10 %** at F300 on + scrap. `min_ticks` 3 is essentially the factory's own structure - its + 6.5 % engrave jobs put 100 us pulses 1.54 ms apart, against 1.64 ms for + `min_ticks` 3 at that density - and 6 is outside anything the factory + does. Below ~5 % no pulse shape reaches the tube: the interval grows as + 1/density, so 1 % implies an 11 ms gap, five times what already failed. - **Cooling operating point**: 40 % heater duty, 50 s window, flow-rise threshold 14.4 °C, re-checks every 150 s. Below ~40 % duty the stagnant loop sheds the heater's output by convection well enough to mimic flow (at 30 %, @@ -1113,6 +1126,13 @@ Open items only. Anything closed is in `CAMPAIGN-LOG.md`. With a minimum in place the low end is decoupled from the base period, so the period is free to be chosen on other grounds. It stays at 20. + **The low end is a scaling problem, not a modulation one.** The band + this tube gives is ~5 % density to strike and ~10 % to mark (facts + bank); below that the pulse interval outruns the discharge whatever the + pulse shape. So a commanded 1 % can only be made useful by mapping it + onto that band, which is what the factory does and what `$35` is under + this model. + Owed: the user-facing scale. The factory maps its whole 1-100 power scale onto density 18.9-79.5 % (fit from the three captures; Full Power is off that line at ~99.7 %), so its "1 %" is the bottom of the band diff --git a/docs/CAMPAIGN-LOG.md b/docs/CAMPAIGN-LOG.md index bded739..c58f2ab 100644 --- a/docs/CAMPAIGN-LOG.md +++ b/docs/CAMPAIGN-LOG.md @@ -2981,15 +2981,39 @@ against the result rather than for it — this ladder started at MPos 0,0 after the controller restart, so it may be on different material than the stacked Y=0/24/48/72 runs. -Owed next: whether a longer minimum reaches further down (`min_ticks = 6`, -213 µs, is set on the bench for the next ladder), and then the user-facing -scale. Under this model `$35` and `$36` are a density floor and ceiling, so -mapping S onto the usable band is a settings choice rather than new code, but -the floor's value wants a finer ladder than the 10 %→20 % step. The trick has -a ceiling of its own: a longer minimum at fixed dose means longer gaps, and -once gap × feed approaches the beam spot a line dots. At 5 mm/s a 4.5 ms gap -is 22 µm against a ~200 µm spot; at 2000 mm/min it is 150 µm, where dotting -would start to show. +### The sixth ladder: a longer minimum is worse, and why + +`min_ticks = 6` (213 µs), same ladder otherwise. **It broke 5 % striking** — +seven current segments again, boundaries at 14.5, ~19.85, 25.2, 30.4, 35.9 +and 41.1 s, segments 4.4–4.9 s with none double-length, fire spanning +9.5 → 46.0 s = 36.5 s against 41.4 s for eight rungs, and the flat saturated +tail anchoring rung 8. Seven rungs marked, matching. + +The arithmetic explains it. Below the minimum the model emits `min` ticks +every `min/on` periods, so the interval between pulse starts is + + interval = min_ticks × tick / density + +and **the base period cancels** — which retroactively explains why periods +10, 20 and 40 gave identical results in the first three ladders. At 5 % +density that is 2.26 ms at `min_ticks` 3, which struck, against 4.51 ms at 6, +which did not. Doubling the minimum doubles the gap as well as the pulse, and +the gap is what decides: the discharge is re-struck each pulse and past +roughly 2–4 ms it has decayed too far to catch. + +That also puts `min_ticks` 3 at the factory's own operating point — its 6.5 % +engrave jobs place 100 µs pulses 1.54 ms apart, against 1.64 ms for +`min_ticks` 3 at that density — and puts 6 outside anything the factory does, +in the direction that fails. The bench is back at 3. + +**Measured band for this tube: strikes from ~5 %, marks from ~10 % at F300.** + +Which closes the pulse-structure route to a usable 1 %. The interval grows as +1/density, so 1 % implies an 11 ms gap, five times what already failed — +no pulse shape reaches down there. The low end is a scaling problem: map the +user's 1–100 onto the band that works, via `$35` as the density floor, which +is what the factory does and why its cut scale starts at 18.9 % while its +engraves reach 6.5 %. Both sit inside the band measured here independently. ## Superseded status notes