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Update WIRING.md

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Thaddeus Hughes
2026-05-26 12:37:12 -05:00
parent e90aef454c
commit 487f47b023
1 changed files with 19 additions and 26 deletions
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docs/WIRING.md
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@@ -18,10 +18,10 @@ This is how I have my LinuxCNC machine wired. I put a linuxCNC box in place of a
The encoders for both motors and the standard TRAK encoders use the same Amphenol CPC connector. 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. 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. Peak-peak voltage is 2.7V.
| Pin | Signal | Color (in PC) | | Pin | Signal | Color (in PC) |
| --- | ------ | ------------- | | --- | -------- | ------------- |
| 1 | B- | White | | 1 | B- | White |
| 2 | 5V | Red | | 2 | 5V | Red |
| 3 | B+ | Blue | | 3 | B+ | Blue |
@@ -30,9 +30,9 @@ The encoders are differential 5V output. They might have an index pulse but I wa
| 6 | N/C | | | 6 | N/C | |
| 7 | N/C | | | 7 | N/C | |
| 8 | N/C | | | 8 | N/C | |
| 9 | GND | Black | | 9 | GND/SHLD | Black |
| 10 | GND | Black | | 10 | GND/SHLD | Black |
| 11 | GND | Black | | 11 | GND/SHLD | Black |
| 12 | A- | Yellow | | 12 | A- | Yellow |
| 13 | GND | Black | | 13 | GND | Black |
| 14 | A+ | Green | | 14 | A+ | Green |
@@ -170,19 +170,12 @@ A custom `M101` and `M102` g code enables/disables the z-axis.
- `output-type 1` (PWM + Direction pins) - `output-type 1` (PWM + Direction pins)
- `offset-mode 1` → locked anti-phase / bipolar single-signal: duty cycle directly encodes signed command - `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) - `scale = OUTPUT_SCALE`: X = +1, Y = -1, Z = -1 (sign flips drive polarity to match wiring)
- Duty cycle = `(value/scale + 1) / 2` - peak-peak voltage of 3.3V from the TRAK CNC II control
| 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". You can hear the drives hum/whine at the 50% state. 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". You can hear the drives hum/whine at the 50% state.
**WARNING: ENABLING THE DRIVE WITH THE PWM DISCONNECTED WILL SHOW AS A 0% DUTY CYCLE - CAUSING THE DRIVE TO RUN FULL REVERSE!** My notes say that setting duty cycle to 0 or 100% cause the drive to disable. I'm not sure if this is the case or not. I don't know exactly what the functional band of the PWM is.
### Enable ### Enable