Under development. Based on LinuxCNC specification, with limitations.
| Mode | Description |
|---|---|
| 0 | Uses an external arc voltage input to calculate both Arc Voltage (for Torch Height Control) and Arc OK. |
| 1 | Uses an external arc voltage input to calculate Arc Voltage (for Torch Height Control). Uses an external Arc OK input for Arc OK. |
| 2 | Uses an external Arc OK input for Arc OK. Use external up/down signals for Torch Height Control. |
| Setting | Modes | Description |
|---|---|---|
| $351 - Delay | 0,1,2 | This sets the delay (in seconds) measured from the time the Arc OK signal is received until Torch Height Controller (THC) activates. |
| $352 - Threshold (V) | 0,1,2 | This sets the voltage variation allowed from the target voltage before for THC makes movements to correct the torch height. |
| $353 - P Gain | - | This sets the Proportional gain for the THC PID loop. This roughly equates to how quickly the THC attempts to correct changes in height. |
| $354 - I Gain | - | This sets the Integral gain for the THC PID loop. Integral gain is associated with the sum of errors in the system over time and is not always needed. |
| $355 - D Gain | - | This sets the Derivative gain for the THC PID loop. Derivative gain works to dampen the system and reduce over correction oscillations and is not always needed. |
| $356 - VAD Threshold (%) | - | (Velocity Anti Dive) This sets the percentage of the current cut feed rate the machine can slow to before locking the THC to prevent torch dive. |
| $357 - Void Override (%) | - | This sets the size of the change in cut voltage necessary to lock the THC to prevent torch dive (higher values need greater voltage change to lock THC) |
| Setting | Modes | Description |
|---|---|---|
| $358 - Fail Timeout | 0,1,2 | This sets the amount of time (in seconds) PlasmaC will wait between commanding a "Torch On" and receiving an Arc OK signal before timing out and displaying an error message. |
| $359 - Retry Delay | 0,1,2 | This sets the time (in seconds) between an arc failure and another arc start attempt. |
| $360 - Max Retries | 0,1,2 | This sets the number of times PlasmaC will attempt to start the arc. |
| $361 - Voltage Scale | - | This sets the arc voltage input scale and is used to display the correct arc voltage. |
| $362 - Voltage Offset | - | This sets the arc voltage offset and is used to display zero volts when there is zero arc voltage input. |
| $363 - Height Per Volt | - | This sets the distance the torch would need to move to change the arc voltage by one volt. Used for manual height manipulation only. |
| $364 - Ok High Voltage | - | This sets the voltage threshold below which Arc OK signal is valid. |
| $365 - Ok Low Voltage | - | This sets the voltage threshold above which the Arc OK signal is valid. |
| Setting | Description |
|---|---|
| $366 - Arc voltage port | This sets which analog input port to use for the arc voltage signal. Set to -1 to not use any.1 |
| $367 - Arc ok port | This sets which digital input port to use for the arc ok signal. Set to -1 to not use any.2 |
| $368 - Cutter down port | This sets which digital input port to use for the cutter down signal. Set to -1 to not use any. |
| $369 - Cutter up port | This sets which digital input port to use for the cutter up signal. Set to -1 to not use any. |
1 This pin/port is required to enable voltage controlled THC.
2 This pin/port is required to enable the plugin.
Tip: use the $PINS command to list available pins. The port number is the number following the "Aux in" text, an example: [PIN:P3.2,Aux in 0,P0].
| Bit | Value | Description |
|---|---|---|
| 0 | 1 | Enable virtual ports. |
| 1 | 2 | Sync Z position. Update the Z position when THC control ends. |
Add the Value fields for the functionality to enable to get the one to use for the setting.
Note
Virtual ports will shadow any real ports with the same port number. Some dummy ports may also be added.
Virtual ports are controlled by regular M-Codes.
-
M62 P2will disable THC (Synchronized with Motion) -
M63 P2will enable THC (Synchronized with Motion) -
M64 P2will disable THC (Immediately) -
M65 P2will enable THC (Immediately) -
M67 E3 Q-Velocity Reduction (Immediately) -
M68 E3 Q-Velocity Reduction (Synchronized with Motion)
The Q-word for M67 and M68 is the percentage of the programmed feed rate the actual feed rate will be changed to.
The minimum percentage allowed is 10%, values below this will be set to 10%.
The maximum percentage allowed is 100%, values above this will be set to 100%.
The plugin can load and partially make use of LinuxCNC and/or SheetCam style material files. Loading is from either a SD card or from root mounted littlefs file system.
The following files are currently loaded from if present:
- LinuxCNC: /linuxcnc/material.cfg
- SheetCam: /sheetcam/default.tools
Additionally materials can be modified or added by LinuxCNC style magic gcode comments.
To select the material to use M190P<n> where <n> is the material number.
If NGC parameter support is enabled in the controller the feedrate from the selected material can be set by adding F#<_hal[plasmac.cut-feed-rate]> to the gcode file.
Currently loaded materials can be output to the sender console with the $EM command, the output is in a machine readable format.
Note
Settings updated via magic comments are currently not written back to the material file.
Driver must support a number of auxiliary I/O ports, at least one digital input for the arc ok signal.
Some drivers support the MCP3221 I2C ADC, when enabled it can be used for the arc voltage signal.
LinuxCNC documentation linked to above.
2025-02-23