Optical QC: EtherCAT control plan with geizhals.de prices

User, 19 Oct 2026: plan the current EtherCAT setup, keep the 100 W servo,
check prices on geizhals.de.

- New docs/equipment/inline-qc-control-plan.md: decisions, bus layout
  (drives at the end of the line because the A6-200EC takes control
  power from the main supply), I/O list for EL1809/EL2809/EL3152/EL5101
  and the drive touch probe, PDO and DC notes from the A6-EC manual,
  geizhals.de price table (EUR 1,891.60 to 2,104.39 + USD 246.58 for the
  servo kits, THB 80k to 88k), NixOS/EtherCrab software, safety circuit
  (PNOZ s3, two contactors, dump valve), bench test with pass marks
  (parts about THB 64k, all reused), build order, spares, open points.
- EL3102 replaced by EL3152: the optoNCDT 1420 output is 4 to 20 mA.
- Spindle encoder index goes to an EL5101 instead of the drive touch
  probe; encoder 2,000 to 2,500 pulses.
- BOM: control lines split per part with geizhals.de prices (+30% high
  end for shipping and Thai duty/VAT, estimate); total USD 16,912 to
  33,061 (THB 0.56M to 1.09M). Doc, render caption and fleet calculator
  text now say USD 17k to 33k.
- README links the plan.

docs/equipment/inline-optical-qc.md

@@ -19,7 +19,7 @@ parts:
 - a servo turntable with a centring chuck;
 - an edge PC running open-source vision software on NixOS.
 
-The hardware costs about USD 16k to 33k per station (bill of materials,
+The hardware costs about USD 17k to 33k per station (bill of materials,
 partly estimates). At launch one station serves both presses, the Duplex
 system and the Classic, and it checks the records after they have cooled
 (decided October 2026; see [where it sits](#where-it-sits)). A concept model of the station, an aluminium
@@ -249,14 +249,14 @@ October 2026). The conveyor uses the same kit, so one spare covers both.
   divided encoder output: its CN1 port carries five inputs, two of them
   touch probes, and three outputs
   ([A6-EC manual](https://www.omc-stepperonline.com/download/A6-EC_series_servo_drive_manual.pdf)).
-  So an incremental encoder (RS-422 line driver, 2,500 to 5,000 pulses a
+  So an incremental encoder (RS-422 line driver, 2,000 to 2,500 pulses a
   turn) sits on the spindle shaft. Its A/B signals clock both line-scans
   directly (Basler racer 2 encoder control,
   [Basler](https://docs.baslerweb.com/encoder-control)), so line timing
   never passes through software, and it measures the spindle itself
-  rather than the motor behind the belt. Its index pulse goes to the
-  drive's touch-probe input, which latches the servo position at the same
-  mark every turn. The scan, the laser traces and the servo then share
+  rather than the motor behind the belt. The same line also runs to an
+  EtherCAT encoder terminal (EL5101), which counts A/B and latches the
+  index once a turn. The scan, the laser traces and the servo then share
   one angle reference.
 - **STO version, looked at in October 2026.** StepperOnline sells the
   A6-EC drive with Safe Torque Off only from 400 W: A6-EC400H2B1-M17-STO
@@ -283,7 +283,7 @@ station controller needs to run the station. Lights, drives and cylinders are in
 | 8 MP colour area camera, GigE, 16 mm lens, ring light | 2: top and bottom | Basler ace 2 a2A2840-14gcPRO | label gate, 520 mm from the infeed | right label on the right side, print, label centring; the top camera also reads the stamper number in the run-out | 1,119 (Basler web shop); lens and ring light 300 to 800 (estimate) |
 | Laser distance sensor | 2 | Micro-Epsilon optoNCDT 1420 | under the record, at 90 and 130 mm radius; analog output to the EtherCAT analog input | warp: height traced round two circles during the turn | from EUR 470 list; ILD1420-25 about 1,600 at a reseller |
 | Servo encoder, 17-bit | 2: spindle and conveyor | StepperOnline A6-EC100L2A1-M17 kit | in each motor; position over EtherCAT | spindle angle for the sequence and the warp traces; conveyor travel | in the kit, 123.29 |
-| Incremental encoder, RS-422 line driver, 2,500 to 5,000 pulses a turn | 1 | Omron E6B2-CWZ1X class | on the spindle shaft | A/B clock both line-scans; the index latches the servo position through the drive's touch probe | 60 to 300 (estimate) |
+| Incremental encoder, RS-422 line driver, 2,000 to 2,500 pulses a turn | 1 | Omron E6B2-CWZ1X class | on the spindle shaft | A/B clock both line-scans; A/B and the index go to the EL5101 encoder terminal, which counts the spindle angle | 53 to 282 (geizhals.de, October 2026) |
 | Diffuse photoelectric sensor | 3 | any industrial make | looking up through the open centre: infeed, label trigger, outfeed | a record at the infeed starts the cycle; the trigger fires the label cameras; a full outfeed holds the next record | 50 to 150 (estimate) |
 | Through-beam photoelectric sensor | 1 pair | any industrial make | across the conveyor at the inspection position | the record's leading edge; stops the belts over the chuck | 50 to 150 (estimate) |
 | Cylinder position switch | 6 | SMC D-M9 class | lift (up, down), reject pusher (home, out), mandrel (open, clamped) | confirms each move before the next step | 25 to 60 (estimate) |
@@ -314,12 +314,14 @@ every 28 s; together that is 5 to 6 records a minute, against the 10 to
 carried to the pusher.
 
 **Control: EtherCAT** (decided October 2026; it replaces the small PLC
-of the first draft).
+of the first draft). The full plan, with the I/O list, geizhals.de
+prices, safety circuit, bench test and build order, is in
+[inline-qc-control-plan.md](inline-qc-control-plan.md).
 
-- **Station controller:** a fanless mini PC, Intel N100 class with two
-  Intel i226 ports, from USD 162 on Alibaba to USD 279 to 469 at retail
-  ([listing](https://cards.keenable.ai/w/01a15225-b50f-7e20-b3c2-e5fdaafae28c),
-  [plugpcs](https://plugpcs.com/mini)). It runs NixOS with the PREEMPT_RT
+- **Station controller:** a fanless mini PC, Intel N100 with Intel
+  i226-V ports, EUR 394 to 456 on
+  [geizhals.de](https://geizhals.de/mini-pc-barebone-netzwerk-pc-intel-n100-a2926989.html)
+  (October 2026). It runs NixOS with the PREEMPT_RT
   kernel, declared in the plant's clan like the edge PC. It is the
   EtherCAT master and runs the station sequence, which we write
   ourselves; there is no PLC.
@@ -334,18 +336,20 @@ of the first draft).
     Its native igc driver for the i226 is listed for the 6.12 kernel, so
     with IgH, pin the 6.12 LTS kernel
     ([IgH device drivers](https://docs.etherlab.org/ethercat/1.6/doxygen/devicedrivers.html)).
-- **On the bus, in one line:** the spindle drive, the conveyor drive, and
-  an EK1100 coupler with EL1809 (16 inputs: photoelectric sensors,
-  cylinder switches, door and e-stop status), EL2809 (16 outputs: valves,
-  stack light) and EL3102 (two analog inputs for the warp lasers;
-  [Beckhoff](https://www.beckhoff.com/en-us/products/i-o/ethercat-terminals/el-ed3xxx-analog-input/el3102.html)).
-  The cycle is 1 ms with distributed clocks. The spindle runs in cyclic
-  synchronous position mode, the conveyor in cyclic synchronous velocity.
+- **On the bus, in one line:** an EK1100 coupler with EL1809 (16
+  inputs: photoelectric sensors, cylinder switches, door and e-stop
+  status), EL2809 (16 outputs: valves, stack light), EL3152 (two 4 to
+  20 mA inputs for the warp lasers) and EL5101 (spindle encoder), then
+  the spindle drive and the conveyor drive at the end of the line. The
+  small A6-200EC takes its control power from the main supply, so it
+  leaves the bus when the safety contactors open; at the end it cuts
+  nothing else off. The cycle is 1 ms with distributed clocks. The
+  spindle runs in cyclic synchronous position mode, the conveyor in
+  cyclic synchronous velocity.
 - **Warp traces:** the lasers are sampled in the same cycle as the
-  spindle position, so each trace comes with its angles: about 1,000
-  points a turn at 1 ms (our arithmetic). The EL3102 takes ±10 V; if the
-  lasers are ordered with a current output, an EL3152 (4 to 20 mA) takes
-  its place.
+  spindle encoder count, so each trace comes with its angles: about
+  1,000 points a turn at 1 ms (our arithmetic). The optoNCDT 1420 has a
+  4 to 20 mA output, hence the EL3152 rather than a voltage terminal.
 - **Safety stays hardwired:** the e-stop and the door switch sit on a
   safety relay that drops a contactor in the drive supply. The 100 W kit
   has no STO input; in the A6-EC list, STO versions start at 400 W.
@@ -379,8 +383,8 @@ By group, per station:
 | Handling | 1.9k to 4.5k | guided lift cylinder, 100 W EtherCAT spindle servo, spindle head with mandrel, rodless cylinder, pneumatics |
 | Vision | 7.7k to 12.5k | 2 line-scans, 2 colour cameras, lenses, 2 coaxial, 4 dark-field and 2 backlights, 2 ring lights, controllers |
 | Sensors | 1.5k to 4.6k | 2 laser distance sensors, presence and stop sensors, cylinder switches, spindle encoder |
-| Control | 3.6k to 8.0k | EtherCAT controller and I/O, edge PC with GPU, HMI, safety, cabinet and wiring |
-| **Total** | **16k to 33k (0.53M to 1.09M THB)** | thermal camera (USD 2.1k to 3.0k) not included |
+| Control | 4.4k to 8.1k | EtherCAT controller and I/O, edge PC with GPU, HMI, safety, cabinet and wiring |
+| **Total** | **17k to 33k (0.56M to 1.09M THB)** | thermal camera (USD 2.1k to 3.0k) not included |
 
 **Open points for the machine builder.**
 
@@ -423,7 +427,7 @@ October 2026).
 - **What it gains.**
   - Warp and centring are measured on settled records, so the reading is
     the release value; no separate sampling of cooled records is needed.
-  - One station instead of two: USD 16k to 33k instead of 50k to 105k
+  - One station instead of two: USD 17k to 33k instead of 50k to 105k
     (estimates).
   - The Classic needs no change to its unloader.
   - The questions about warm records drop out: sag on the rim belts and
@@ -508,9 +512,9 @@ simulated.
 
 | Item | Estimate |
 |---|---|
-| Hardware per station, from the [bill of materials](inline-qc-station/inline-qc-station-bom.csv) | USD 16k to 33k (0.53M to 1.09M THB) |
+| Hardware per station, from the [bill of materials](inline-qc-station/inline-qc-station-bom.csv) | USD 17k to 33k (0.56M to 1.09M THB) |
 | First station: frame build and machined parts, lighting trials, software, training data | 2 to 4 person-months, USD 15k to 40k (our own team with a local machine builder) |
-| Launch plant: one station for both presses, after cooling | the hardware above, USD 16k to 33k, plus the first-station work (about USD 31k to 73k in all, 1.0M to 2.4M THB) |
+| Launch plant: one station for both presses, after cooling | the hardware above, USD 17k to 33k, plus the first-station work (about USD 32k to 73k in all, 1.1M to 2.4M THB) |
 
 All three figures are estimates; the bill of materials names a source for each priced line. They fit inside the existing metrology
 launch-tier line, USD 170k to 460k for XRF, inline vision and the audio
@@ -542,13 +546,12 @@ vision share is not yet confirmed.
    cycle, side; see [digital factory](../digital-factory.md)).
 4. **Warp sensors.** Choose between two point lasers and a line profiler
    once the trials show whether a thickness map is worth the extra cost.
-5. **EtherCAT bench.** Before the frame is built, run one A6-EC kit, an
-   EK1100 with the three terminals and the spindle encoder from the mini
-   PC with EtherCrab: distributed clocks at 1 ms, cyclic synchronous
-   position on the drive, the touch probe latching the encoder index, and
-   the cycle jitter measured under load. The drive's EtherCAT description
-   file is on the StepperOnline product page. If EtherCrab falls short on
-   the drive, repeat the test with the IgH master.
+5. **EtherCAT bench.** Before the frame is built, run one A6-EC kit, the
+   EK1100 with its terminals and the spindle encoder from the mini PC
+   with EtherCrab: eight tests and pass marks are in the
+   [control plan](inline-qc-control-plan.md#7-bench-test-before-the-frame-is-built)
+   (about THB 64,000 of parts, all reused in the station). If EtherCrab
+   falls short on the drive, repeat the test with the IgH master.
 6. **Acceptance test.** Write it before ordering. It should cover the
    detection rate per defect class on the trial set, the false-reject
    rate on good records (black and specials apart), and every result