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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/Config_Reference.md | 7 | ||||
| -rw-r--r-- | docs/Overview.md | 2 | ||||
| -rw-r--r-- | docs/Using_PWM_Tools.md | 67 |
3 files changed, 76 insertions, 0 deletions
diff --git a/docs/Config_Reference.md b/docs/Config_Reference.md index 1c86acf5..cca85161 100644 --- a/docs/Config_Reference.md +++ b/docs/Config_Reference.md @@ -2529,6 +2529,13 @@ pin: #shutdown_value: # The value to set the pin to on an MCU shutdown event. The default # is 0 (for low voltage). +#maximum_mcu_duration: +# The maximum duration a non-shutdown value may be driven by the MCU +# without an acknowledge from the host. +# If host can not keep up with an update, the MCU will shutdown +# and set all pins to their respective shutdown values. +# Default: 0 (disabled) +# Usual values are around 5 seconds. #cycle_time: 0.100 # The amount of time (in seconds) per PWM cycle. It is recommended # this be 10 milliseconds or greater when using software based PWM. diff --git a/docs/Overview.md b/docs/Overview.md index 94ffd8fa..a82f372b 100644 --- a/docs/Overview.md +++ b/docs/Overview.md @@ -46,6 +46,8 @@ communication with the Klipper developers. with Klipper. - [Skew correction](skew_correction.md): Adjustments for axes not perfectly square. +- [PWM tools](Using_PWM_Tools.md): Guide on how to use PWM controlled + tools such as lasers or spindles. - [G-Codes](G-Codes.md): Information on commands supported by Klipper. # Developer Documentation diff --git a/docs/Using_PWM_Tools.md b/docs/Using_PWM_Tools.md new file mode 100644 index 00000000..3947e183 --- /dev/null +++ b/docs/Using_PWM_Tools.md @@ -0,0 +1,67 @@ +This document describes how to setup a PWM-controlled laser or spindle +using `output_pin` and some macros. + + +## How does it work? +With re-purposing the printhead's fan pwm output, you can control +lasers or spindles. +This is useful if you use switchable print heads, for example +the E3D toolchanger or a DIY solution. +Usually, cam-tools such as LaserWeb can be configured to use `M3-M5` +commands, which stand for _spindle speed CW_ (`M3 S[0-255]`), +_spindle speed CCW_ (`M4 S[0-255]`) and _spindle stop_ (`M5`). + + +**Warning:** When driving a laser, keep all security precautions +that you can think of! Diode lasers are usually inverted. +This means, that when the MCU restarts, the laser will be +_fully on_ for the time it takes the MCU to start up again. +For good measure, it is recommended to _always_ wear appropriate +laser-goggles of the right wavelength if the laser is powered; +and to disconnect the laser when it is not needed. +Also, you should configure a safety timeout, +so that when your host or MCU encounters an error, the tool will stop. + +For an example configuration, see `config/sample-pwm-tool-cfg`. + +## Current Limitations + +There is a limitation of how frequent PWM updates may occur. +While being very precise, a PWM update may only occur every 0.1 seconds, +rendering it almost useless for raster engraving. +However, there exists an [experimental branch](https://github.com/Cirromulus/klipper/tree/laser_tool) with its own tradeoffs. +In long term, it is planned to add this functionality to main-line klipper. + +## Commands + +`M3/M4 S<value>` : Set PWM duty-cycle. Values between 0 and 255. +`M5` : Stop PWM output to shutdown value. + +## Laserweb Configuration + +If you use Laserweb, a working configuration would be: + + GCODE START: + M5 ; Disable Laser + G21 ; Set units to mm + G90 ; Absolute positioning + G0 Z0 F7000 ; Set Non-Cutting speed + + GCODE END: + M5 ; Disable Laser + G91 ; relative + G0 Z+20 F4000 ; + G90 ; absolute + + GCODE HOMING: + M5 ; Disable Laser + G28 ; Home all axis + + TOOL ON: + M3 $INTENSITY + + TOOL OFF: + M5 ; Disable Laser + + LASER INTENSITY: + S |