Question regarding Z offset

[szafranski]

Hi! Awesome initiative! Just a quick question. Is Z offset being calibrated automatically or not? There are 2 informations - one that states that is it not supported and one that it is. Thanks!

[frap129]

It is measured automatically (no paper test or testing), but you have to run the command manually. See https://github.com/frap129/OpenQ1/blob/main/docs/Calibrating-Z-Offset.md

[szafranski]

In the link you sent there is exact description of paper test in point 5

…

On Tue, Nov 12, 2024 at 16:26 Joe Maples ***@***.***> wrote: It is measured automatically (no paper test or testing), but you have to run the command manually. See https://github.com/frap129/OpenQ1/blob/main/docs/Calibrating-Z-Offset.md — Reply to this email directly, view it on GitHub <#19 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFUHCAG7VBXVWSY7J447KIT2AIMZ7AVCNFSM6AAAAABRS4G4FWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDINZQHAZTINBXG4> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[frap129]

Ah I see the confusion. When I said paper test, I mean the standard 3d printer "put a piece of paper under the nozzle, and repeatedly adjust the z position by 0.05mm until the resistance feels right", whereas this module only asks you to make sure the nozzle isn't physically touching the bed.

[frap129]

I should note, that step only exists because some people have adjusted the bed screws on their Q1, which breaks the auto-calibrating system. The sensors are attached through the bed screws and require a specific amount of pressure to be accurate.

[aidan-gibson]

I'm also having issues with this. I click home all (manually inputting XYZ values in fluidd doesn't work for me), then type AUTO_Z_CALIBRATE and get !! Probe triggered prior to movement every time.

[frap129]

I'm also having issues with this. I click home all (manually inputting XYZ values in fluidd doesn't work for me), then type AUTO_Z_CALIBRATE and get !! Probe triggered prior to movement every time.

Have you adjusted the bed screws at all? "triggered prior to movement" means that at least one of the 3 sensors has enough pressure on it to trigger, even though the toolhead has not moved yet. If you have not adjusted them, it could just be that the sensors are acting weird. For some reason, they need to be jiggled up and down a bit to work right. By default we do this 4 times, but you can override it by adding

[auto_z_offset]
prepare_gcode:
    SET_PIN PIN=bed_sensor VALUE=0
    G91
    {% set i = 4 %}
    {% for iteration in range(i|int) %}
        G1 Z1 F900
        G1 Z-1 F900
    {% endfor %}
    G90
    SET_PIN PIN=bed_sensor VALUE=1

to your printer.cfg and increasing the value of i. QIDI Stock firmware used to do it 42 times, but have since reduced it to 7 times in updates

[aidan-gibson]

Thanks, I'll try that out! I haven't adjusted the bed screws at all.

[supjj]

I was getting the  Probe triggered prior to movement intermittently, I did not touch the bed screws. I found that heating the bed slightly has solved the problem for me. I created a macro that automates the process Also below is a safety cutoff timer if like me other get easy distracted.

[gcode_macro _TZ_PREP]
description: #Prepares and prompts for auto Z calibrate
gcode:
  {% set BED_TEMP = params.BED_TEMP|default(32)|float %}
  {% set EXTRUDER_TEMP = params.EXTRUDER_TEMP|default(150)|float %}
  M140 S{BED_TEMP} # set bed temp no wait
  M104 S{EXTRUDER_TEMP} # set extruder temperature no wait 
  G28 # home all
 # G90 # absolute positioning
  TEMPERATURE_WAIT SENSOR=heater_bed MINIMUM={BED_TEMP * 0.95} MAXIMUM={BED_TEMP * 3.5} # wait for bed temp range min set to 105 at max
  TEMPERATURE_WAIT SENSOR=extruder MINIMUM={EXTRUDER_TEMP} MAXIMUM={EXTRUDER_TEMP+100} # Wait for hotend temp range min set to 250 at max
  AUTO_Z_CALIBRATE
  M140 S0 # set bed temperature to zero
  M118 The bed temperature has been set to zero
  M118 1.Adjust the Z axis while performing the paper drag test until adequate friction can be felt between the bed and the nozzle  2.Confirm the settings via the save config prompt on the interface to save and restart
  UPDATE_DELAYED_GCODE ID=_T_PREP DURATION=180
  M118 3 minutes countdown until hotend safety shutdown
  
[delayed_gcode _T_PREP]
gcode:
  M104 S0 # set extruder temperature to zero
  M118 The Extruder temperature has been set to zero # safety timeout extruder temperature cut