Auto Z offset calibration
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@Phaedrux No it came without any information. then just test it thank you
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it works fine now.
here is the gcode if anyone is interestedvar errorfix = 0.000 ; constant offset G31 Z0 ; set Z-offset to Z=0 echo >"0:/sys/config_probe.g" "G31 Z0" M291 S3 R"Heating up nozzle" P"Wait for the nozzle to reach printing temperatures" M568 P0 S210 ; set tool 0 (primary hotend) temperature to 210c T0 ; select tool 0 (primary hotend) M116 P0 H5 ; wait for temperature to reach within 5c of set temperature M300 S666 P666 ; beep M291 S3 R"Automatic Z Offset Calibration" P"Press OK to continue, or CANCEL to abort" M291 S3 R"Homing axes" P"Remove the puck. The printer will home the X, Y, and Z axises without the puck" M98 P"config_probe.g" ; Load BLTouch probe settings M280 P0 S60 I1 ; clear any probe errors G29 S2 ; cancel mesh bed compensation G91 ; relative positioning M913 X50 ; X axis 50% power G1 H2 Z5 F200 ; lift Z relative to current position G28 X0 U0 Y0 ; Home X,U and Y axis ; go back a few mm M913 X100 ; X axis 100% power G90 ; absolute positioning G1 X{move.axes[0].min+175} Y{move.axes[1].min+110} F6000 ; move to center G1 F600 ; reduce speed G30 ; home Z by probing the bed G31 Z0 ; set Z-offset to Z=0 M564 H1 S0 ; Negative movements are allowed G29 S2 ; cancel mesh bed compensation G90 ; absolute positioning G1 Z35 ; raise Z to 35mm M83 ; relative extruder moves G1 E-5 F300 ; retract 5mm of filament G4 P0 ; wait for the moves to finish M291 S3 R"Clean the nozzle" P"The nozzle has been pre-heated. Clean it from any plastic debris" G1 X100 Y200 F6000 ; go to X100, Y200 G4 P0 ; wait for movements to have stopped M300 S666 P666 ; beep M291 S3 P"Place the offset tool below the nozzle and press OK to perform the macro, or CANCEL to abort" G4 P200 ; wait 200ms G91 ; relative moves G1 H1 Z-19 F50 ; move 19mm down, stop when hitting the offset tool (but don't risk crashing the bed) G92 Z0 ; set current position as Z=0 G4 P200 ; wait 200ms G1 Z11 F200 ; move up 11mm G91 ; relative moves G1 X{sensors.probes[0].offsets[0] * -1} Y{sensors.probes[0].offsets[1] * -1} F1500 ; move nozzle so that BLTouch is in it's position G90 ; absolute moves G30 S-3 ; probes Z and adjusts the probe trigger height to match the actual stop height. G4 P200 ; wait 200ms G91 ; relative movement M568 P0 S0 ; set tool 0 temperatures to 0 var Z_auto_offset = {sensors.probes[0].triggerHeight+var.errorfix} ; math to calculate the BLTouch offset if var.Z_auto_offset < 0.01 M291 S2 R"The nozzle has not touched the puck." P"Please check the guide for troubleshooting" echo "The nozzle has not touched the puck. Please check the guide for troubleshooting" echo >"0:/sys/config_probe.g" "G31 Z-3" elif var.Z_auto_offset >= 0.01 & var.Z_auto_offset < 3.5 echo >"0:/sys/config_probe.g" "G31 Z"^{var.Z_auto_offset} M291 S2 R"Z-offset has been stored" P"the Z-offset has been stored in the config_probe.g file. Verify the value stored with the value displayed in the console" echo "the Z-offset has been stored in the config_probe.g file. The Z-offset is", var.Z_auto_offset, "mm. Remove the offset tool and place it back in the box" elif var.Z_auto_offset >= 3.5 M291 S2 R"Z-Offset is too high" P"Please verify the probe height using the probe-calibration" echo "Z-Offset is too high. Please verify the probe height using the probe-calibration" echo >"0:/sys/config_probe.g" "G31 Z-3" M564 S1 H1 ; Negative movements are forbidden M300 S666 P666 ; beep G91 ; relative moves G1 Z5 ; lift nozzle up 5mm G90 ; absolute moves T-1 ; deselect all tools M18 ; release steppers -
@Proschi78
Very interesting - I will likely try something similar. Do you have a sense at the accuracy / effectiveness?
Specifically, it seems that there likely would be some mechanical hysteresis in the switch (i.e. measured zero will be a bit lower than the nominal top of the puck). Then the BLT comes along and triggers, perhaps moving the top of the puck, perhaps not.
In other words, it seems there would be some offset between the two trigger points and that could vary from puck-to-puck or in similar solutions that use a microswitch.
What I'm thinking is (maybe) set up the nozzle itself as one side of the "switch" (gnd) and using a puck with a fixed plate as the other side(+ve). That would eliminate the variation that could occur due to a microswitch.
Of course, it may be prudent to have a little "give" in the puck to guard against over zealous probing by the nozzle but stiff enough to (effectively) not move during the probes.
Thoughts?
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@stuartofmt This puck works with gnd and + on the nozzle. Of course there is a small - value, but this is very consistent and can be compensated with var errorfix = 0.000.
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@Proschi78 said in Auto Z offset calibration:
@stuartofmt This puck works with gnd and + on the nozzle. Of course there is a small - value, but this is very consistent and can be compensated with var errorfix = 0.000.
Many thanks for the input and also the gcodes. I'll print up a puck and give it a whirl. Never did like the sliding paper thing
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I would like to automatically measure the z offset of the left and right extruder.
How can I retrieve the current z height with a meta code and then display it?
would like to go to the puk with the left extruder and save the z height as a variable.
then go to the puk with the right extruder and subtract the variable from this position and display it -
@Proschi78
Use global variables to capture the results ? Then use M291 or M117 to display ? -
I tried that, but something is still wrong
; Idex Auto Nozzle Offset Tool 1 M291 S3 R"Automatic Idex Offset Calibration" P"Press OK to continue, or CANCEL to abort" M291 S3 R"Homing axes" P"Remove the puck. The printer will home the X, Y, and Z axes without the puck" G28 T0 G90 ; absolute positioning G1 X175 Y110 Z5 F3000 M291 S3 R"Heating up nozzle" P"Wait for the nozzle to reach printing temperatures" M568 P0 S200 ;T0 200c M568 P1 S200 ;T1 200c M116 P0 H5 ;Wait for Temp +-5c G1 Z50 F800 M291 S3 R"Clean the nozzle" P"The nozzle has been pre-heated. Clean it from any plastic debris" G1 Z25 F800 G4 P0 M300 S666 P666 ; beep M291 S3 P"Place the offset tool below the nozzle and press OK to perform the macro, or CANCEL to abort" G29 S2 G4 P200 ; wait 200ms G1 H1 Z-19 F50 ; move 19mm down, stop when hitting the offset tool (but don't risk crashing the bed) {global.tool0 = move.axes[2].machinePosition} ; Store the current Z position in tool0 G1 Z25 F3000 G28 X0 T1 G1 U175 Y110 Z25 F3000 G1 H1 Z-20 F50 ; Move Z-axis down 20 mm {global.tool1 = move.axes[2].machinePosition - global.tool0} ; Calculate the difference between current Z position and tool0 and store in tool1 {echo "The difference between the two nozzle heights is: " + str(round(global.tool1, 3)) + " mm."} ; Output the difference to the console G4 S15 G1 Z25 F500 G28 U0 -
@Proschi78
Have you declared the global variables ?
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@Proschi78 said in Auto Z offset calibration:
{global.tool0 = move.axes[2].machinePosition}
Should be
set global.tool0 = move.axes[2].machinePosition
however it will always be zero (or whatever your axis minima is set to with M208)
Also no need for curly brackets here.Likewise the second calculation is going to return zero (axis minima) because you use H1
I feel you should be using H4 on the second test at least and that creating the firt global is largely redundant.I can't test, but maybe
G1 Z50 F800 M291 S3 R"Clean the nozzle" P"The nozzle has been pre-heated. Clean it from any plastic debris" G1 Z25 F800 G4 P0 M300 S666 P666 ; beep M291 S3 P"Place the offset tool below the nozzle and press OK to perform the macro, or CANCEL to abort" G29 S2 G4 P200 ; wait 200ms G1 H1 Z-19 F50 ; move 19mm down, stop when hitting the offset tool (but don't risk crashing the bed) M400 set global.tool0 = move.axes[2].machinePosition ; Store the current Z position in tool0 G1 Z25 F3000 G28 X0 T1 G1 U175 Y110 Z25 F3000 G1 H4 Z-20 F50 ; Move Z-axis down 20 mm M400 set global.tool1 = move.axes[2].machinePosition - global.tool0 ; Calculate the difference between current Z position and tool0 and store in tool1 echo "The difference between the two nozzle heights is: " ^ global.tool1 ^ " mm." ; Output the difference to the console G4 S15 G1 Z25 F500 G28 U0