Z-IR height is too high off the bed when printing



  • I have reset my IR Probe 10 times using the wiki page, it triggers the the height at 1.683mm.

    I set up the nozzle to just touch the paper with a little bit of drag, sent the code M564 S0 and then the G92 Z0 to zero the head, i then move the nozzle 5mm above the bed and the duet web control panel shows it at 5.00mm I then send the G30 S-1 to probe and this gives a trigger height of 1.683 in the g-code console panel, i repeat this about 3 times to get a consitant 1.683 this then displays in the console and then displays the 6.683 in the web control panel.

    I edit the System Editor and edit the config.g file. Set the Z parameter in the G31 command to the trigger height of 1.683 that was reported. Save the file.

    But i do not seem to have a config-overide.g file anywhere.

    I then go to print, it then homes the nozzle and the panel dispalys 6.683mm after moving the bed down 5mm, when i go to actual printing mode, the nozzle distance is about 1.683mm above the bed ?? and the print then fails to stick to the bed as the nozzle is too high.

    Can anyone please help.


  • administrators

    I suspect that you are homing Z using a G1 S1 Z command instead of a G30. Please post your homez.g and homeall.g files, and see https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Homing_Z_using_a_Z_probe.



  • I am also having the same problem, I always seem to never get a true grasp on how to set the Z offset correctly. I am noticing if I hold a thick piece of paper up to the sensor the LEDs go off twice, once at a distance of 20mm approx. and a second time at which I would assume is the correct height that I am getting, 1.649mm. I updated to 2.03 firmware and now it is working similar to Shaunppl. I am using Phaedrux's Z probe macro and getting 1.649mm consistently when the IR probe is triggered. Here are my files, currently in the config.g the offset is set to 0mm.

    7_1564018675514_homez.g 6_1564018675514_homey.g 5_1564018675514_homex.g 4_1564018675514_homeall.g 3_1564018675514_home.g 2_1564018675514_config-override.g 1_1564018675513_config.g 0_1564018675513_bed.g



  • @underdonesushi

    What is your bed surface? IR probe performance can be affected by the bed surface reflectivity. Especially if there are patterns or logos on it.

    I notice that in your homez and homeall you aren't using the same location to probe the bed, and the locations you are using are not in the center of the bed. For best results you should move the probe to the center of the bed for establishing the Z height. Ideally it should be the same spot you've used to measure your trigger height.

    Homez

    G1 X15 Y-10 F9000 ; go to first probe point
    G30               ; home Z by probing the bed
    

    Homeall

    G1 X15 Y15 F9000        ; go to first bed probe point and home Z
    G30                     ; home Z by probing the bed
    

    Your G31 command in config.g lacks any X and Y offsets for the probe.
    G31 P500 X0 Y0 Z2.0 This would only be accurate if your probe is also your nozzle. You didn't mention what your probe type is, but this thread is about an IR probe, so if we assume that's what you have, then you should measure the distance in X and Y between the nozzle and the probe and enter it into G31.

    https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Measuring_Probe_X_Y_Offset

    I also see that you are loading the heightmap in config.g. This isn't recommended because you haven't yet determined what Z0 is at bootup. Remove G29 S1 from config.g and add it either to the end of your homez and homeall, or add it to the slicer start gcode after the g28.

    https://duet3d.dozuki.com/Wiki/Using_mesh_bed_compensation#main



  • @phaedrux Bed surface - Similar to matte finish (no logo) to Buildtak but has a magnetic sheet underneath, Easy-Peelzy - https://www.kickstarter.com/projects/1011650524/easy-peelzy?ref=nav_search&result=project&term=easy peelzy

    homez + homeall - I am still learning how to correctly code the duetwifi but, you are saying the two areas thare are bold should be exactly the same? I am using X15 Y15 because the IR Probe is on the front of my E3D v6 and so I wanted to make sure it was reading a consistent part of the bed.

    G31 Command - I had the printer working with the IR probe before moving it, I don't think I had a value inputted in the G31 P500 X0 Y0 Z2.0

    Heightmap - Yes I had the printer working with the heightmap, could this be throwing it off? To remove the heightmap and start over would I just delete the heightmap.g?

    thanks phaedrux



  • @underdonesushi said in Z-IR height is too high off the bed when printing:

    @phaedrux Bed surface - Similar to matte finish (no logo) to Buildtak but has a magnetic sheet underneath, Easy-Peelzy - https://www.kickstarter.com/projects/1011650524/easy-peelzy?ref=nav_search&result=project&term=easy peelzy

    It's hard to tell from the photos but that does look like a suitable surface for the IR probe. It isn't overly shiny by the looks of it and no graphics on it.

    homez + homeall - I am still learning how to correctly code the duetwifi but, you are saying the two areas thare are bold should be exactly the same? I am using X15 Y15 because the IR Probe is on the front of my E3D v6 and so I wanted to make sure it was reading a consistent part of the bed.

    Yes, you should alter the G1 X Y command that comes before the G30 to move the probe into the center of the bed before probing, and that location should be the same in both homeall and homez.

    G31 Command - I had the printer working with the IR probe before moving it, I don't think I had a value inputted in the G31 P500 X0 Y0 Z2.0
    You need to measure the distance between the probe and the nozzle in X and Y and enter the values in G31 so that the offset between the nozzle and probe can be taken into account. See the link above for description of exactly how to go about it.

    Heightmap - Yes I had the printer working with the heightmap, could this be throwing it off? To remove the heightmap and start over would I just delete the heightmap.g?
    Every time you run G29 the heightmap.g is replaced with a new one. G29 S1 loads the saved heightmap.

    What I am saying you should do is remove the G29 S1 from config.g so it isn't loading the heightmap right at boot up. Instead put G29 S1 at the end of homeall and homez after the G30. That way your Z position is known before the heightmap is loaded. That should help correct your Z height being off.

    thanks phaedrux

    Hope that helps.



  • @phaedrux

    Bed surface - I don't think the bed surface is the problem at all.

    Homez.g -
    0_1565544073906_homez.g

    Homeall.g -
    0_1565544108688_homeall.g

    Heightmap - I removed the heightmap file and disabled it in the config.g correctly I think...

    I have been working on and off on this Z offset problem for months now, literally no clue. I have been using this one today, I need this to work it is killing me not being able to print anything. I am at a loss, I had it working somehow then moved and reconnected it to the wifi and it just reads too high now @Phaedrux ---https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height

    I noticed when I do M500 P31 and check my config.override.g I get this in the Z-probe section, It seems to be reading 3 tools?
    0_1565544250358_config-override.g

    I have also included my config.g file --- I took a little inspiration from your layout.
    0_1565544976932_config.g



  • @underdonesushi said in Z-IR height is too high off the bed when printing:

    I noticed when I do M500 P31 and check my config.override.g I get this in the Z-probe section, It seems to be reading 3 tools?

    Hmm, I'm not too sure about that. Are you using M500 G31 in your workflow, or just for testing? I'd probably delete these lines from config-override.

    What do you have in your slicer start gcode?



  • @phaedrux I think I figured it out... I bought sensor #1 Feb 28th, 2018 and sensor #2 on August 1st, 2018.
    Had always used sensor #1 and had it working for approx, 2 months? Then I moved and it stopped working. Just switched the sensor out with #2 to see if it would work and it activated correctly above the bed surface and is printing which is a HUGE relief. Thank you so much guys for your help, I will let you know if this was the end all be all solution.

    @dc42 Sensor #1 was activating the lights twice, once at approximately 6mm above the bed and if I turned axis limits off it activated again at the correct height. Is there any reason for this or is it a dud sensor? I can take a photo of both next to each other for you. They both say they are V1.3 on the rear but the #2 board has no diagnosis holes right of the chip, and the holes (right of R1 and right of R3 are soldered up).

    Thanks again!

    Ian



  • @underdonesushi hi,
    I am having the exact same problem and honestly I am few moments from throwing this sensor out of the window and go to BLTouch whom I have on other printer and never had problem with him.
    As you said, my probe trigger in two spots on 2mm which is correct and on 6mm which is not.
    If I do z axis calibrate I put a paper on the middle of the bed when I get the grip feel I do G92 z0 and then move the z 5 mm down and when I hit G30 s-1 I get a good values.
    But if I move the z10 mm down before the G30 and then hit it i get 6.4mm which is too far.
    The problem begins few days ago.. And solve itself yesterday for few prints and today it got mad again..
    All this time I am using the same black mat sticker on the bed in the same room, which I even tried to turn light off to see if this what cause the problem and still..
    I am using duet wifi and the ir probe with the smd.
    Is there a way to calibrate the sensor itself?!
    And do you think it's a faulty ir sensor?
    It's not so cheap sensor to just order one to test it but i would be really disappointed if it gone..
    My BLTouch works for a year+ and double the use and it's mechanical and still work way better.
    0_1567732783098_IMG-20190905-WA0026.jpeg
    In the photo I took G30 on 5mm first and then on 10mm I used the panel thats why you don't see the moving.
    the trigger result are really accurate on the 6mm and on the 2mm it's almost the same result every time the way only ir probe can..
    BTW how the hell its even workson 6+mm?! in the technical page it's written it can only works 2-3 mm..



  • Now im the complete opposite, I have removed x3 genuine BL Touch units from various printers because they provided me with unreliable results and are I feel they were mechanically inferior. Whereas with the IR sensor I have had nothing but plug and play results.

    Im running 6 IR probes on my 7 home printers (the 7th has a smart effector) and I also have 11 (soon to be 12) IR probes on my work units and they all "just work"

    I have only ever followed the guide on David's own page which I feel covers all the prerequisites to getting the probe up and running flawlessly.
    I would advise you go have a read of that page and follow it to the LETTER, as there is thousands of these probes in the wild working perfectly.

    IR SENSOR

    You need to logically and methodically work through the setup and make sure everything is as it should be and logically find the issue.

    While frustration is understandable it is not productive and to be saying

    "I am few moments from throwing this sensor out of the window and go to BLTouch"

    Wont really induce much sympathy to help you, and again while we understand frustration please remember that any suggestions are peoples good intentions that are provided to try to help you, so as the old saying goes "dont bite the hand that feeds you"

    So again I say, methodically and logically work through the issue go look at David's page.

    A thought that just sprang to mind, is to also make sure that the wiring from the duet to the probe is 100% intact.



  • @calvinx thanks for your informative and really fast reply!!.
    I didn't quit understand why you took the "throw out the window" so hard haha.
    This is an electronic part that sit few inchs from 300 Celsius so it can go faulty.. And since I didn't see any guide to test the ir probe itself, without duet like with arduino only,i wanted to go with the easy solution, sometimes the time you spent on diagnostic part just not worth it and the smart thing would be to buy a new one, especially when you know it worked in the past in the exact same rig so you know something happened just to him.

    In the end after a week of fighting with him and at some point even took him off and map the surface manually i found the problem.
    And I only blame Murphy's law! Haha.
    In the middle of the ir sensor there is a black capacitor,i guess when i replaced the nozzle to steel one i touched it and bent it by i dunno less then 10 degrees, you can notice it is bent but only from short distance.
    So I bent him back with zero force and tweezers and wolla!! It is now only see the right distance that is 2.something mm.
    So I suspect that the angle and the fact that the capacitor reflection are high it somehow reflected the ir even from 6mm.
    Because the capacitor is well solderded to the sensor so it wasn't a short of any kind.

    Bottom line, my fault as usual 😅

    But thanks again for your help!



  • @eran898

    For you to admit the problem was down to human error and not the hardware, only confirms what I was saying.

    glad you worked it out.

    There are instructions on how to install/configure the IR sensor on non duet electronics on David's Website.


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