BLTouch working
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I micro stepped through homez and am still seeing z axis movement invert after homing. I am also confused by the G92 setting. my z stop appears to be .3mm below printhead should i do G92 Z.3 or move sensor? i also tried skipping the last G90 command at end thinking that was inverting axis movement but same result. afte homing z goes backward and bed crashes into bottom of machine if i dont turn it off. even a manual move of .1 sends bed all 450mm down.
; homez.g
; called to home the Z axisG91 ; relative mode
G1 Z-4 F200 ; lower bed 4mm to ensure it is below the switch trigger height
G90 ; back to absolute mode
G1 X128 Y141 F2000 ; put head wherever you want it to be when you home Z (omit this line if it doesn't matter)
G91 ; relative mode
G1 Z450 S1 F100 ; move Z up until the switch triggers
G90 ; back to absolute mode
G92 Z0 ; tell the firmware that we are at Z=0mm -
I don't understand your Z homing file. You have that G1 Z450 S1 command to move the print head up or bed down until the endstop is triggered, which suggests that you have a Z-max endstop switch. But then you have a G92 Z0 command which suggests you have a Z-min endstop switch. Which do you have?
I also have a feeling that you may have configured your Z axis to move in the wrong direction. If you have a print head that moves in Z, positive Z movement should move the print head up. If you have a moving bed, positive Z movement should move the bed down.
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i think you are right on point! my printer has print head mounted to x axis rail at fixed height. bed moves up and down. z0 is at top where end stop is located. Give me a minute to digest this and i bet you already gave me the answer i was looking for! Thanks again! You really do a great job here and it is much appreciated. I do tech support for a living and am often frustrated by silly questions. i suspect you have the patience of a saint. LOL
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updated z home and inverted z axis in config.g so + = bed moves down. Moving Z before homing + = down. Z home appears to work too but after it completes i am at z end stop aka z0 and z axis movement is inverted again. If i move g + it goes up and hits print head but - doesn't move at all. Something is inverting z movement during\after homing???
; homez.g
; called to home the Z axisG91 ; relative mode
G1 Z4 F200 ; lower bed 4mm to ensure it is below the switch trigger height
G90 ; back to absolute mode
G1 X128 Y141 F2000 ; put head wherever you want it to be when you home Z (omit this line if it doesn't matter)
G91 ; relative mode
G1 Z-450 S1 F100 ; move Z up until the switch triggers
G90 ; back to absolute mode
G92 Z0 ; tell the firmware that we are at Z=0mmconfig.g
; Drives
M569 P0 S0 ; Drive 0 goes Backwards
M569 P1 S0 ; Drive 1 goes Backwards
M569 P2 S0 ; Drive 2 goes Backwards
M569 P3 S0 ; Drive 3 goes Backwards -
tried to recreate issue by moving to middle of z and activating end stop switch with my finger. that is not causing z axis to invert and it does appear to work correctly so has to be something in the software right? with end stop triggered, - movements dont work but + do and move the bed down. clueless as to why z axis inverts after z homing
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Is your Z switch at the bottom or the top of the bed travel?
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top
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Your Z homing file looks ok to me now, except that you may want to back off Z a little and re-home at a slower speed, as the standard X and Y homing files do. Also adjust the Z parameter in your G92 Z0 command to be the exact Z height after the switch is triggered.
What M208 commands do you have in config.g? After homing, the limits set by M208 are enforced.
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when z end stop triggers, ph is about 2mm above bed. should i move sensor up so z=0 or is there some sort of offset here?
updated z home as recommended i think…
config.g
M208 X3 Y0 Z0S1 ; Set axis minima
should there be a space between Z0 and S1?; homez.g
; called to home the Z axisG91 ; relative mode
G1 Z10 F200 ; lower bed 10mm to ensure it is below the switch trigger height
G90 ; back to absolute mode
G1 X128 Y141 F2000 ; put head wherever you want it to be when you home Z (omit this line if it doesn't matter)
G91 ; relative mode
G1 Z-450 S1 F100 ; move Z up until the switch triggers
G1 z10 F6000
G1 z-450 F360 S1 ; Move slowly to z axis endstop once more
G90 ; back to absolute mode
G92 Z0 ; tell the firmware that we are at Z=0mm -
There should be a space in that command, but in most cases you can get away without one.
It's best if your Z homing switch triggers a little before Z=0. If it's triggering at exactly 2.0mm, change G92 Z0 in homez.g to G92 Z2.0
HTH David
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i also had a max z value wrong on the other end of m208 maximum which i believe was what caused z to invert after homing.
z homing works now but does not do it twice like i thought it would. bl touch appears to be working at start it is lit up solid red but it does not deploy probe during bed leveling so it still crashes ph into bed. manual retract and deploy work but when i start bed config, it does not deploy probe. i even added manual deploy at start but it is not working either
#Retractprobe.g
M280 P3 S90 I1Deployprobe.g
M280 P3 S10 I1
; bed.g
; called to perform automatic bed compensation via G32; Clear any bed transform
M561; Home all axes
G28
;# Deployprobe.g
M280 P3 S10 I1
; Probe the bed at 5 points
G30 P0 X15 Y15 H0 Z-99999
G30 P1 X15 Y268 H0 Z-99999
G30 P2 X255 Y268 H0 Z-99999
G30 P3 X255 Y15 H0 Z-99999
G30 P4 X128 Y138 H0 Z-99999 S
;#Retractprobe.g
M280 P3 S90 I1 -
i found a 2nd command in bed.g that cleared home results. i removed that and bl touch started working but did not deploy probe before test started. I added deploy and retract directly to bed.g and that helped . It moved to 1st probe spot and probed successfully but then bed drops below probes reach and it tries to continue probing but eventually errors out. Why is bed moving down after 1st probe? i cant seem to remember the setting for probe offset. i know i am offset on x axis about 28mm but i am not sure about z end stop position setting or why bed drops below probe after 1st probe deploys successfully.
; bed.g
; called to perform automatic bed compensation via G32; Clear any bed transform
M561;# Deployprobe.g
M280 P3 S10 I1
; Probe the bed at 5 points
G30 P0 X15 Y15 H0 Z-99999
G30 P1 X15 Y268 H0 Z-99999
G30 P2 X255 Y268 H0 Z-99999
G30 P3 X255 Y15 H0 Z-99999
G30 P4 X128 Y138 H0 Z-99999 S
;#Retractprobe.g
M280 P3 S90 I1Config.g
; BLTouch
M307 H3 A-1 C-1 D-1
M558 P5 X0 Y0 Z1 H3 F200 T5000 -
when bltouch is extended, it is roughly 3mm below print head. do i need to set this somewhere? I also had a x minimum of 3 so when it homed it would go to x=0 and be outside area. not sure if that was causing issues or not but set it to 0 just in case.
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Thanks David, sorry i was delayed in seeing your last reply. i added 2mm but same result. bed moves down below pin after 1st probe point fires. i also added a space but agree it made no difference.
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You need to set the Zprobe trigger height in the G31 command in config.g. You may also need to increase the dive height, which is the H parameter in the M558 command.
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Thanks David, I was printing test cubes and stuff late into the night. Cant wait to get this dialed in! I will give that a try and let you know how i make out.
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I have had the BLTouch not fire the pin a couple times when setting it up. What seemed to have happened is that it faulted before trying to fire the pin so nothing happens, that the Duet does not know that it didn't fire.
This is relatively easy to resolve by sending a reset code, but here is my dilemma. What happens if the probe is faulted and you when you try to home?
This happened while I was sitting there so was able to prevent damage no idea why the probe was faulted, but what if I fail to notice in time the next time..
Anyway I was curious if anyone has seen this issue and what safeguards they have used to prevent catastrophe
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if it homes but then fails to activate for the probe it will only go the dive height distance before erroring but on the homing process i believe its just a bed crash.
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i noticed my bltouch fires twice at start up. if you are at z home, the probe hits the bed and errors out. no idea if this is what is causing your issue… BTW, i also noticed loose connection on the 50 pin jack causing bltouch to go on and off sometimes during movement. I hope you have better connectors than i do.
To whomever was asking for a copy of my config, sorry but my pc died and i am running on an old xp system at the moment soat a standstill as far as being able to work on the printer. Hope to have resolved soon but definitely intend on sharing as soon as i am back up. I also appear to have a bizarre z movement issue and am wondering if others wired dual motors on y and z of if they are using an expansion of some sort? left y motor never even gets warm but right does.
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I don't actively have an issue, I am just want to prevent a possible future issue.
The frame of my printer in acrylic and if I had to bet which would give first the steppers or the acrylic I wouldn't bet on the acrylic even though its high quality stuff.
One thing I am thinking of is sending a reset pulse before I start but still that doesn't guarantee anything.
Another thing might be adding some sort of emergency stop on the bed somehow. If it deflects the rods when it hits the hotend I don't think it would hurt much, but it bowed the acrylic a little before I was able to stop it (again this is when I was still setting it up)
In any case while the BLTouch is awesome there is little to no security with it.
