docs

docs/WIRING.md

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+
+This is how I have my LinuxCNC machine wired. I put a linuxCNC box in place of a Southwestern Industries TRAK CNC II control box. I am reusing the TRAK drives, motors, and encoders. Eventually, I switched to using linear encoders instead of the TRAK encoders.
+
+| Mesa card | Role                            |
+| --------- | ------------------------------- |
+| 6i24-16   | FPGA card (PCIe host interface) |
+| 7i52S     | Servo interface daughter card   |
+| 7i37TA    | Isolated I/O daughter card      |
+|           |                                 |
+
+![[pc_front.jpg]]
+![[cbox_back.jpg]]
+![[cbox_inside.jpg]]
+
+## TRAK Encoder Pinout
+
+The encoders for both motors and the standard TRAK encoders use the same Amphenol CPC connector.
+
+The encoders are differential 5V output. They might have an index pulse but I wasn't using it. The Z axis has the same pinout.
+
+| Pin | Signal | Color (in PC) |
+| --- | ------ | ------------- |
+| 1   | B-     | White         |
+| 2   | 5V     | Red           |
+| 3   | B+     | Blue          |
+| 4   | N/C    |               |
+| 5   | N/C    |               |
+| 6   | N/C    |               |
+| 7   | N/C    |               |
+| 8   | N/C    |               |
+| 9   | GND    | Black         |
+| 10  | GND    | Black         |
+| 11  | GND    | Black         |
+| 12  | A-     | Yellow        |
+| 13  | GND    | Black         |
+| 14  | A+     | Green         |
+![[ampconns.jpg]]
+## Linear Encoder Pinout (DB9)
+
+I switched to some linear encoders that have a D-sub connector. They are also 5V differential output, and nearly the same resolution, resulting in very easy switchover.
+
+| Pin | Signal | Color (in PC) |
+| --- | ------ | ------------- |
+| 1   | A-     | Yellow        |
+| 2   | GND    | Black         |
+| 3   | B-     | White         |
+| 4   | N/C    | N/C           |
+| 5   | Z-     | Tan           |
+| 6   | A+     | Green         |
+| 7   | 5V     | Red           |
+| 8   | B+     | Blue          |
+| 9   | Z+     | Maroon        |
+
+
+## DB37 Pinout
+
+The DB37 cable contains drive signals and motor encoder signals.
+
+*This pinout was determined by probing. I'm not sure what some of the pins do; some of the pins labelled GND or 5V might actually be an index pulse or something.*
+
+
+| Pin   | Signal     | Notes     |
+| ----- | ---------- | --------- |
+| 1-5   | ??? (N/C?) |           |
+| 6     | YB-        | Y Encoder |
+| 7     | YB+        | Y Encoder |
+| 8     | YA+        | Y Encoder |
+| 9     | YA-        | Y Encoder |
+| 10    | XB+        | X Encoder |
+| 11    | XB-        | X Encoder |
+| 12    | XA+        | X Encoder |
+| 13    | XA-        | X Encoder |
+| 14    | XENW       | X Enable  |
+| 15    | XENR       | X Enable  |
+| 16    | YENW       | Y Enable  |
+| 17    | YENR       | Y Enable  |
+| 18    | ZENW       | Z Enable  |
+| 19    | ZENR       | Z Enable  |
+| 20    | ??? (N/C?) |           |
+| 21    | 5V         |           |
+| 22    | 5V         |           |
+| 23    | GND        |           |
+| 24    | GND        |           |
+| 25    | 5V         |           |
+| 26    | 5V         |           |
+| 27    | GND        |           |
+| 28    | GND        |           |
+| 29    | 5V         |           |
+| 30    | 5V         |           |
+| 31-37 | GND        |           |
+
+# MESA Cards
+
+![[mesa_cards.jpg]]
+## 7i37TA
+
+Three enables are used - one for the X and Y axes, one for the z axis, and one for the spindle. This allows the z axis to be disabled independently for manual drilling operations.
+
+Each works by connecting a pair of wires. Made = enabled.
+
+The spindle only has enable; direction and speed is manually controlled.
+
+A custom `M101` and `M102` g code enables/disables the z-axis.
+
+| Enable  | 7i37TA Pin | 6i24-16 Pin | Wire Color             |
+| ------- | ---------- | ----------- | ---------------------- |
+| XY      | OUT6+      | 46          | White & Green to black |
+| Z       | OUT4+      | 44          | Red to black           |
+| Spindle | OUT3+      | 41          | White to Green         |
+
+## 7i52S
+
+#### Encoder connector
+(This is for connector 0; carries over to channels 0-4 as well)
+
+*Five encoder inputs are used - x, y, and z each use one without index pulse, and x and y have a secondary linear encoder that does use the index pulse*
+
+*Sometimes the A-channels and B-channels are flipped, at least color-wise.*
+
+| Pin | Signal | Function | Wire Color |
+| --- | ------ | -------- | ---------- | 
+| 1   | QA0    | A+       | Green      |
+| 2   | /QA0   | A-       | Yellow     |
+| 3   | GND    | GND      | Black      |
+| 4   | QB0    | B+       | Blue       |
+| 5   | /QB0   | B-       | White      |
+| 6   | +5V    | 5V       | Red        |
+| 7   | IDX0   | I+       | Maroon     |
+| 8   | /IDX0  | I-       | Tan        |
+
+#### Differential Output Connector
+
+*Three differential outputs are used - one for each x, y, and z*
+
+| Pin | Signal | Function | Color |
+| --- | ------ | -------- | ----- |
+| 1   | GND    |          | N/C   |
+| 2   | GND    |          | N/C   |
+| 3   | TX0A   | TXA+     | White |
+| 4   | /TX0A  | TXA-     | Green |
+| 5   | TX0B   |          | N/C   |
+| 6   | /TX0B  |          | N/C   |
+| 7   | +5V    |          | N/C   |
+| 8   | +5V    |          | N/C   |
+
+#### HAL Channel assignments
+
+| Axis     | Encoder ch   | PWM ch      | Notes                     |
+| -------- | ------------ | ----------- | ------------------------- |
+| X linear | `encoder.00` | —           | Joint position feedback   |
+| Y linear | `encoder.01` | —           | Joint position feedback   |
+| Z linear | `encoder.02` | —           | Joint position feedback   |
+| X motor  | `encoder.03` | —           | Velocity/damping feedback |
+| Y motor  | `encoder.04` | —           | Velocity/damping feedback |
+| Z motor  | (none)       | —           | No dual loop on Z         |
+| X drive  | —            | `pwmgen.00` | Differential PWM out      |
+| Y drive  | —            | `pwmgen.02` | Differential PWM out      |
+| Z drive  | —            | `pwmgen.04` | Differential PWM out      |
+
+## Servo Drive Config
+
+### PWM
+
+- Carrier: **15.5 kHz** (`hm2_5i24.0.pwmgen.pwm_frequency 15500`)
+- `output-type 1` (PWM + Direction pins)
+- `offset-mode 1` → locked anti-phase / bipolar single-signal: duty cycle directly encodes signed command
+- `scale = OUTPUT_SCALE`: X = +1, Y = -1, Z = -1 (sign flips drive polarity to match wiring)
+- Duty cycle = `(value/scale + 1) / 2`
+
+| Commanded value | Duty cycle | Meaning      |
+| --------------- | ---------- | ------------ |
+| -1.0            | 0 %        | full reverse |
+| -0.5            | 25 %       | half reverse |
+| 0.0             | **50 %**   | stop         |
+| +0.5            | 75 %       | half forward |
+| +1.0            | 100 %      | full forward |
+
+When the enable line is deasserted the pwmgen output is forced off (not 50%), so the amp sees a distinct disabled state vs. "commanded zero".
+
+### Enable
+
+Enable lines are switched by 7i37TA isolated MOSFET outputs (`OBITn+`/`OBITn-`). Per the 7i37 manual, a **low** FPGA pin turns the MOSFET **on**. HAL sets `invert_output true` on the enable GPIOs, so HAL `enable=TRUE` → FPGA-low → MOSFET on → contact **closed**.
+
+| HAL enable | FPGA pin | MOSFET | Contact | Drive    |
+| ---------- | -------- | ------ | ------- | -------- |
+| TRUE       | LOW      | ON     | made    | enabled  |
+| FALSE      | HIGH     | OFF    | broken  | disabled |
+
+Fail-safe: cable cut, 5 V loss, or hm2 unconfigured all leave the MOSFET off → contact open → drive disabled.
+
+![[cbox_bottom.jpg]]

readme.md

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 # Lagun Mill - LinuxCNC
 
+For wiring - see [docs/WIRING.md](docs/WIRING.md).
+
 ## Docs
 
 - [nc_files/MACROS.md](nc_files/MACROS.md) — macro subroutine reference (drill, pocket, frame, slot, bore, polygon)