251 lines
12 KiB
Markdown
251 lines
12 KiB
Markdown
# BL-Touch
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## Connecting BL-Touch
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A **warning** before you start: Avoid touching the BL-Touch pin with
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your bare fingers, since it is quite sensitive to finger grease. And
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if you do touch it, be very gentle, in order to not bend or push
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anything.
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Hook up the BL-Touch "servo" connector to a `control_pin` according to
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the BL-Touch documentation or your MCU documentation. Using the
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original wiring, the yellow wire from the triple is the `control_pin`
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and the white wire from the pair is the `sensor_pin`. You need to
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configure these pins according to your wiring. Most BL-Touch devices
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require a pullup on the sensor pin (prefix the pin name with "^"). For
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example:
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```
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[bltouch]
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sensor_pin: ^P1.24
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control_pin: P1.26
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```
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If the BL-Touch will be used to home the Z axis then set `endstop_pin:
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probe:z_virtual_endstop` and remove `position_endstop` in the `[stepper_z]` config section,
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then add a `[safe_z_home]` config section to raise the z axis, home the xy axes,
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move to the center of the bed, and home the z axis. For example:
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```
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[safe_z_home]
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home_xy_position: 100,100 # Change coordinates to the center of your print bed
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speed: 50
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z_hop: 10 # Move up 10mm
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z_hop_speed: 5
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```
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It's important that the z_hop movement in safe_z_home is high enough
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that the probe doesn't hit anything even if the probe pin happens to
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be in its lowest state.
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## Initial tests
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Before moving on, verify that the BL-Touch is mounted at the correct
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height, the pin should be roughly 2 mm above the nozzle when retracted
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When you turn on the printer, the BL-Touch probe should perform a
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self-test and move the pin up and down a couple of times. Once the
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self-test is completed, the pin should be retracted and the red LED on
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the probe should be lit. If there are any errors, for example the
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probe is flashing red or the pin is down instead of up, please turn
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off the printer and check the wiring and configuration.
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If the above is looking good, it's time to test that the control pin
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is working correctly. First run `BLTOUCH_DEBUG COMMAND=pin_down` in
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your printer terminal. Verify that the pin moves down and that the red
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LED on the probe turns off. If not, check your wiring and
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configuration again. Next issue a `BLTOUCH_DEBUG COMMAND=pin_up`,
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verify that the pin moves up, and that the red light turns on
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again. If it's flashing then there's some problem.
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The next step is to confirm that the sensor pin is working correctly.
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Run `BLTOUCH_DEBUG COMMAND=pin_down`, verify that the pin moves down,
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run `BLTOUCH_DEBUG COMMAND=touch_mode`, run `QUERY_PROBE`, and verify
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that command reports "probe: open". Then while gently pushing the pin
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up slightly with the nail of your finger run `QUERY_PROBE` again.
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Verify the command reports "probe: TRIGGERED". If either query does
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not report the correct message then check your wiring and
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configuration again. At the completion of this test run `BLTOUCH_DEBUG
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COMMAND=pin_up` and verify that the pin moves up.
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After completing the BL-Touch control pin and sensor pin tests, it is
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now time to test probing, but with a twist. Instead of letting the
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probe pin touch the print bed, let it touch the nail on your finger.
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Position the toolhead far from the bed, issue a `G28` (or `PROBE` if
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not using probe:z_virtual_endstop), wait until the toolhead starts to
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move down, and stop the movement by very gently touching the pin with
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your nail. You may have to do it twice, since the default homing
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configuration probes twice. Be prepared to turn off the printer if it
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doesn't stop when you touch the pin.
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If that was successful, do another `G28` (or `PROBE`) but this time
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let it touch the bed as it should.
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## BL-Touch gone bad
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Once the BL-Touch is in inconsistent state, it starts blinking red.
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You can force it to leave that state by issuing:
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BLTOUCH_DEBUG COMMAND=reset
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This may happen if its calibration is interrupted by the probe being
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blocked from being extracted.
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However, the BL-Touch may also not be able to calibrate itself
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anymore. This happens if the screw on its top is in the wrong position
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or the magnetic core inside the probe pin has moved. If it has moved
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up so that it sticks to the screw, it may not be able to lower its pin
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anymore. With this behavior you need to open the screw and use a
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ball-point pen to push it gently back into place. Re-Insert the pin
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into the BL-Touch so that it falls into the extracted position.
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Carefully readjust the headless screw into place. You need to find the
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right position so it is able to lower and raise the pin and the red
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light turns on and of. Use the `reset`, `pin_up` and `pin_down`
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commands to achieve this.
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## BL-Touch "clones"
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Many BL-Touch "clone" devices work correctly with Klipper using the
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default configuration. However, some "clone" devices may require
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configuration of `pin_up_reports_not_triggered` or
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`pin_up_touch_mode_reports_triggered`.
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Important! Do not configure `pin_up_reports_not_triggered` or
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`pin_up_touch_mode_reports_triggered` to False without first following
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these directions. Do not configure either of these to False on a
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genuine BL-Touch. Incorrectly setting these to False can increase
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probing time and can increase the risk of damaging the printer.
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Some "clone" devices are unable to perform Klipper's internal sensor
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verification test. On these devices, attempts to home or probe can
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result in Klipper reporting a "BLTouch failed to verify sensor state"
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error. If this occurs, then manually run the steps to confirm the
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sensor pin is working as described in the
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[initial tests section](#initial-tests). If the `QUERY_PROBE` commands
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in that test always produce the expected results and "BLTouch failed
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to verify sensor state" errors still occur, then it may be necessary
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to set `pin_up_touch_mode_reports_triggered` to False in the Klipper
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config file.
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A rare number of old "clone" devices are unable to report when they
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have successfully raised their probe. On these devices Klipper will
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report a "BLTouch failed to raise probe" error after every home or
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probe attempt. One can test for these devices - move the head far from
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the bed, run `BLTOUCH_DEBUG COMMAND=pin_down`, verify the pin has
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moved down, run `QUERY_PROBE`, verify that command reports "probe:
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open", run `BLTOUCH_DEBUG COMMAND=pin_up`, verify the pin has moved
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up, and run `QUERY_PROBE`. If the pin remains up, the device does not
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enter an error state, and the first query reports "probe: open" while
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the second query reports "probe: TRIGGERED" then it indicates that
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`pin_up_reports_not_triggered` should be set to False in the Klipper
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config file.
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## BL-Touch v3
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Some BL-Touch v3.0 and BL-Touch 3.1 devices may require configuring
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`probe_with_touch_mode` in the printer config file.
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If the BL-Touch v3.0 has its signal wire connected to an endstop pin
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(with a noise filtering capacitor), then the BL-Touch v3.0 may not be
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able to consistently send a signal during homing and probing. If the
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`QUERY_PROBE` commands in the [initial tests section](#initial-tests)
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always produce the expected results, but the toolhead does not always
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stop during G28/PROBE commands, then it is indicative of this issue. A
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workaround is to set `probe_with_touch_mode: True` in the config file.
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The BL-Touch v3.1 may incorrectly enter an error state after a
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successful probe attempt. The symptoms are an occasional flashing
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light on the BL-Touch v3.1 that lasts for a couple of seconds after it
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successfully contacts the bed. Klipper should clear this error
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automatically and it is generally harmless. However, one may set
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`probe_with_touch_mode` in the config file to avoid this issue.
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Important! Some "clone" devices and the BL-Touch v2.0 (and earlier)
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may have reduced accuracy when `probe_with_touch_mode` is set to True.
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Setting this to True also increases the time it takes to deploy the
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probe. If configuring this value on a "clone" or older BL-Touch
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device, be sure to test the probe accuracy before and after setting
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this value (use the `PROBE_ACCURACY` command to test).
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## Multi-probing without stowing
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By default, Klipper will deploy the probe at the start of each probe
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attempt and then stow the probe afterwards. This repetitive deploying
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and stowing of the probe may increase the total time of calibration
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sequences that involve many probe measurements. Klipper supports
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leaving the probe deployed between consecutive probes, which can
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reduce the total time of probing. This mode is enabled by configuring
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`stow_on_each_sample` to False in the config file.
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Important! Setting `stow_on_each_sample` to False can lead to Klipper
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making horizontal toolhead movements while the probe is deployed. Be
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sure to verify all probing operations have sufficient Z clearance
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prior to setting this value to False. If there is insufficient
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clearance then a horizontal move may cause the pin to catch on an
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obstruction and result in damage to the printer.
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Important! It is recommended to use `probe_with_touch_mode` configured
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to True when using `stow_on_each_sample` configured to False. Some
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"clone" devices may not detect a subsequent bed contact if
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`probe_with_touch_mode` is not set. On all devices, using the
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combination of these two settings simplifies the device signaling,
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which can improve overall stability.
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Note, however, that some "clone" devices and the BL-Touch v2.0 (and
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earlier) may have reduced accuracy when `probe_with_touch_mode` is set
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to True. On these devices it is a good idea to test the probe accuracy
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before and after setting `probe_with_touch_mode` (use the
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`PROBE_ACCURACY` command to test).
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## Calibrating the BL-Touch offsets
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Follow the directions in the [Probe Calibrate](Probe_Calibrate.md)
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guide to set the x_offset, y_offset, and z_offset config parameters.
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It's a good idea to verify that the Z offset is close to 1mm. If not,
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then you probably want to move the probe up or down to fix this. You
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want it to trigger well before the nozzle hits the bed, so that
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possible stuck filament or a warped bed doesn't affect any probing
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action. But at the same time, you want the retracted position to be as
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far above the nozzle as possible to avoid it touching printed parts.
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If an adjustment is made to the probe position, then rerun the probe
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calibration steps.
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## BL-Touch output mode
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* A BL-Touch V3.0 supports setting a 5V or OPEN-DRAIN output mode,
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a BL-Touch V3.1 supports this too, but can also store this in its
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internal EEPROM. If your controller board needs the fixed 5V high
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logic level of the 5V mode you may set the 'set_output_mode'
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parameter in the [bltouch] section of the printer config file to
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"5V".
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*** Only use the 5V mode if your controller boards input line is
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5V tolerant. This is why the default configuration of these BL-Touch
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versions is OPEN-DRAIN mode. You could potentially damage your
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controller boards CPU ***
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So therefore:
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If a controller board NEEDs 5V mode AND it is 5V tolerant on its
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input signal line AND if
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- you have a BL-Touch Smart V3.0, you need the use 'set_output_mode: 5V'
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parameter to ensure this setting at each startup, since the probe
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cannot remember the needed setting.
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- you have a BL-Touch Smart V3.1, you have the choice of using
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'set_output_mode: 5V' or storing the mode once by use of a
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'BLTOUCH_STORE MODE=5V' command manually and NOT using the parameter
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'set_output_mode:'.
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- you have some other probe: Some probes have a trace on the circuit board
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to cut or a jumper to set in order to (permanently) set the output mode.
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In that case, omit the 'set_output_mode' parameter completely.
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If you have a V3.1, do not automate or repeat storing the output mode to
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avoid wearing out the EEPROM of the probe.The BLTouch EEPROM is good for
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about 100.000 updates. 100 stores per day would add up to about 3 years
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of operation prior to wearing it out. Thus, storing the output mode in a
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V3.1 is designed by the vendor to be a complicated operation (the factory
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default being a safe OPEN DRAIN mode) and is not suited to be repeatedly
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issued by any slicer, macro or anything else, it is preferably only to be
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used when first integrating the probe into a printers electronics.
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