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| -rw-r--r-- | docs/Installation.md | 4 | ||||
| -rw-r--r-- | docs/Overview.md | 3 |
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diff --git a/docs/FAQ.md b/docs/FAQ.md new file mode 100644 index 00000000..6fb69b1e --- /dev/null +++ b/docs/FAQ.md @@ -0,0 +1,103 @@ +Frequently asked questions +========================== + +### How do I calculate the step_distance parameter in the printer config file? + +If you know the steps per millimeter for the axis then use a +calculator to divide 1.0 by steps_per_mm. Then round this number to +six decimal places and place it in the config (six decimal places is +nano-meter precision). + +The step_distance defines the distance that the axis will travel on +each motor driver pulse. It can also be calculated from the axis +pitch, motor step angle, and driver microstepping. If unsure, do a web +search for "calculate steps per mm" to find an online calculator. + +### When I restart my micro-controller the device changes to /dev/ttyACM1 + +If the device sometimes changes from /dev/ttyACM0 to /dev/ttyACM1 then +ssh into the host computer and run: ```ls -l /dev/serial/by-id/``` + +The name found in the above command is stable and it is possible to +use it in the config file. For example, an updated config might look +like: +``` +[mcu] +serial: /dev/serial/by-id/usb-UltiMachine__ultimachine.com__RAMBo_12345678912345678912-if00 +``` + +Be sure to copy-and-paste the name from the "ls" command above as the +name will be different on each printer. + +### Can I run Klipper on something other than a Raspberry Pi? + +Klipper only requires Python running on a Linux (or similar) +computer. However, if you wish to run it on a different machine you +will need Linux admin knowledge to install the system prerequisites +for the Linux distribution running on that particular machine. See the +[install-octopi.sh](../scripts/install-octopi.sh) script for further +information on the necessary Linux admin steps. + +### Why can't I move the stepper before homing the printer? + +The code does this to reduce the chance of accidentally commanding the +head into the bed or a wall. Once the printer is homed the software +attempts to verify each move is within the position_min/max defined in +the config file. If the motors are disabled (via an M84 or M18 +command) then the motors will need to be homed again prior to +movement. + +If you want to move the head after canceling a print via Octoprint, +consider changing the Octoprint cancel sequence to do that for +you. It's configured in Octoprint via a web browser under: +Settings->GCODE Scripts + +If you want to move the head after a print finishes, consider adding +the desired movement to the "custom g-code" section of your slicer. + +### Why is the Z position_endstop set to 0.5 in the default configs? + +For cartesian style printers the Z position_endstop specifies how far +the nozzle is from the bed when the endstop triggers. If possible, it +is recommended to use a Z-max endstop and home away from the bed (as +this reduces the potential for bed collisions). However, if one must +home towards the bed then it is recommended to position the endstop so +it triggers when the nozzle is still a small distance away from the +bed. This way, when homing the axis, it will stop before the nozzle +touches the bed. + +Almost all mechanical switches can still move a small distance +(eg, 0.5mm) after they are triggered. So, for example, if the +position_endstop is set to 0.5mm then one may still command the +printer to move to Z0.2. The position_min config setting (which +defaults to 0) is used to specify the minimum Z position one may +command the printer to move to. + +Note, the Z position_endstop specifies the distance from the nozzle to +the bed when the nozzle and bed (if applicable) are hot. It is typical +for thermal expansion to cause nozzle expansion of around .1mm, which +is also the typical thickness of a sheet of printer paper. Thus, it is +common to use the "paper test" to confirm calibration of the Z +height - check that the bed and nozzle are at room temperature, check +that there is no plastic on the head or bed, home the printer, place a +piece of paper between the nozzle and bed, and repeatedly command the +head to move closer to the bed checking each time if you feel a small +amount of friction when sliding the paper between bed and nozzle - if +all is calibrated well a small amount of friction would be felt when +the height is at Z0. + +### I converted my config from Marlin and the X/Y axes work fine, but I just get a screeching noise when homing the Z axis + +Short answer: Try reducing the max_z_velocity setting in the printer +config. Also, if the Z stepper is moving in the wrong direction, try +inverting the dir_pin setting in the config (eg, "dir_pin: !xyz" +instead of "dir_pin: xyz"). + +Long answer: In practice Marlin can typically only step at a rate of +around 10000 steps per second. If it is requested to move at a speed +that would require a higher step rate then Marlin will generally just +step as fast as it can. Klipper is able to achieve much higher step +rates, but the stepper motor may not have sufficient torque to move at +a higher speed. So, for a Z axis with a very precise step_distance the +actual obtainable max_z_velocity may be smaller than what is +configured in Marlin. diff --git a/docs/Installation.md b/docs/Installation.md index 1675f3ba..f5f244ad 100644 --- a/docs/Installation.md +++ b/docs/Installation.md @@ -125,4 +125,6 @@ the "help" command to get a list of other extended commands. Contacting the developers ========================= -See the [contact page](Contact.md) to ask questions or report a bug. +Be sure to see the [FAQ](FAQ.md) for answers to some common questions. +See the [contact page](Contact.md) to report a bug or to contact the +developers. diff --git a/docs/Overview.md b/docs/Overview.md index 38ed9c26..31ba04b9 100644 --- a/docs/Overview.md +++ b/docs/Overview.md @@ -13,7 +13,8 @@ as a reference for the config file. The on tuning the pressure advance config. The [kinematics](Kinematics.md) document provides some technical -details on how Klipper implements motion. +details on how Klipper implements motion. The [FAQ](FAQ.md) answers +some common questions. The history of Klipper releases is available at [releases](Releases.md). See [contact](Contact.md) for information on |