Z home doesn't work since firmware update

Just updated my firmware (to dc42's 57q)... when printing now the nozzle seems to extrude about 1cm above the heatbed.

I've tried homing Zaxis then droping the nozzle until it is just above the headbed and using a G92 Z0 command. I then reun my setbed.g file as usual and go to print but still it extrude about 1cm above the heat bed.

I've also tried recalibrating the Z-probe and put the data into the config on the sd card. still even when running this it prints 1cm above the heat bed.

ANY thoughts???

Hi 88Zombies,

One other person has reported something similar. Please can you tell me:

1. What exactly is in your setbed.g file?

2. Just after running setbed.g in the procedure you are using, manually lower the nozzle to just above the bed (preferably near the centre of the bed). What z-height does it then read? Use the web interface or the M114 command to find out.

3. If you then do G92 Z0, then print, does it print properly?

Edited 2 time(s). Last edit at 03/08/2014 07:09PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hello DC,
not a problem..

1.
file: M557 P0 X60 Y-10
file: M557 P1 X60 Y170
file: M557 P2 X226 Y170
file: M557 P3 X226 Y-10

I noticed that the Y axis can't go to minus figures on axis-homing or manual movement (after reading about grinding i understand the reasoning behind this). It can still reach these positions when running the G32 command after loading the setbed.g so i figured it would be ok to leave the setbed figures..
None the less I am currently in the process of changing these figures.. I've repositioned my paper squares to:

file: M557 P0 X70 Y0
file: M557 P1 X70 Y165
file: M557 P2 X220 Y165
file: M557 P3 X220 Y0

2.
If I run the setbed & lower so the nozle is just above the heat-bed the Z position is at -2.49mm

3.
...... Doing that may have just worked, ive tried a few different variations, i.e homing z, lowering z, using G92 Z0, running set bed.
but I just did as you said, (lowered the nozzle after running set bed and it printed about 1mm above the heatbed) will try one more time....
[EDIT; affraid it hasn't worked, it does print a bit lower but still isn't quite as accurate doing it by eye. I just tried lowering Z -3.5 and was still printing about 1mm above the bed plane.
Also should probably note, setting the Z height after the setbed.g also means the Z axis doesnt make the minute adjustments for bed plane compensation.]

Edited 1 time(s). Last edit at 03/08/2014 08:03PM by 88Zombies.

I think this is a simlar problem I had when using 57 from RepRap (sorry I can't remember the exact version other than it was released on 16th Jan, which was my birthday at the time, so I remembered it).
I'd moved the Hotend to around 100x 10y and set the Z axis with my normal setting 0.1Z (I like to use feelers). Did a GetPos from Pronterface, and it gave a totaly different reading. I repeated doing this 3 times, and each time I got a different reading for Z to the 0.1mm I'd set it to.
I then realised that the Bed Compansation was turned on, and that it was ignoring the current position (X,Y) and taking the Z reading for the default (X,Y) position and replying with a calculated reading. After that I decided to turn the Bed Compensation OFF, and set the Bed up so it was Mech. level.
I had no problems after that.
I can't comment on DCs firmware if the problem has continued because I don't use compensation, but I think if you look at the RepRap Firmware, the setting of the Homing postion ignors the current X,Y position, and your actualy setting the value for the Firmwares default position where ever the HotEnd is.

Hope that Helps....

Kim

PS Personaly I've always found the compensation a pain.... That's why I modified my Sub Bed to be more rigid, and Mech. leveled my Bed.
I think if you look at the Firmware, that the Z0 position has to be done at their definded spot, yet it's not mentioned as such.... I might be wrong, but that was my feeling at the time, so I turned the Compensation off. It also saved lots of wear on the gearing and Z Nut....

Edited 1 time(s). Last edit at 03/08/2014 08:57PM by KimBrown.

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Hi 88Zombies,

Thanks for replying.

1. The latest version of my firmware is 057t, not 057q.

2. Is the G32 command in setbed.g, or are you sending that command manually after sending setbed.g? Please list the entire contents of setbed.g.

3. Setting the Z height after G32 does not cancel the bed compensation. You should still see the Z axis moving during the print as bed compensation is applied (I do), unless the bed is very level.

4. What is at the beginning of the gcode file you are trying to print? In particular, does it contain any homing commands?

5. My firmware prevents you from moving to negative XY positions once homed, except when homing. So I think it may not be processing the bed compensation correctly. I suggest you redefine your Y axis length as 210mm so that you don't need negative Y coordinates. There are two things you need to do. First, put the command M208 Y210 in config.g to define the axis length. Second, modify the homey.g file on the SD card. The original homey.g is this:

G91
G1 Z5 F200
G1 X20 F2000
G90
G90
G92 Y0
G1 Y220 F2000 S1
G92 Y200
G1 Y0
G91
G1 X-20 F2000
G1 Z-5 F200

The simplest fix (which works with all firmware versions) is to change the line G92 Y200 to G92 Y210. If you are running my 057t firmware then you can get rid of all the G92 commands in the file (they are only needed because of a bug that I fixed in that version) and make the Y homing move a relative move:

G91
G1 Z5 F200
G1 X20 F2000
G1 Y220 F2000 S1
G90
G1 Y0
G91
G1 X-20 F2000
G1 Z-5 F200
G90

Whichever fix you choose, you also need to apply it to the y-homing section of the homeall.g file.

Edited 1 time(s). Last edit at 03/09/2014 05:33AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi DC,
Apologies late replying, had a weekend away from the computor + printer at the request of the other half. -.-

1. Affraid i didn't realise there was another update! i downloaded your firmware quite a while ago and was waiting for the right time to install.

2. No i load the setbed and then type G32 as I use pronterface, if i was to put G32 at the end of my setbed g-code, would this allow the file to work on teh web interface? at the moment when on teh web interface i load the setbed.g but nothing happens..

3. + 4. + 5.
I think i figured it out...
I removed the kapton tape, replaced the white squares with larger pieces of white paper...
ammended the location points for the Zprobe... this seemed to work but is still a bit more tempremental than is was with the old reprap firmware...however.
I then calibrated it manually as instructed, and it has worked almost perfectly well. was really happy with the result. thank you ever so much.

Hi 88Zombies,

I think the issue may be that your z-homing point (which is defined in the homez.g and homeall.h files) is not the same as your first bed calibration point. The z-homing point in homez.g is X55 Y0 if you haven't changed it, but you are using X60 Y-10 or X70 Y0. I suggest you do the following, in this order:

1. Sort out your Y axis length and homing so that your coordinates go from Y0 to Y210 (or even a bit greater) - see my reply 2 posts ago.

2. Go back to using smaller white squares if you like. I suggest 15 to 20mm square.

3. Choose your 4 bed compensation points so that the IR sensor head is above the centre of the white tape. Check that when you place the head at a bed compensation point at about the height you specify in your G31 command, the Z-probe reading does not change significantly if you move the head by 1mm in X or Y, in either direction.

4. Edit homez.g and homeall.g so that the Z homing point is the same as your first bed probing point.

Using larger white squares has probably been sufficient to put both the Z homing point and the first bed compensation point over the white tape. But you will get more accurate results if you make them both the same.

I'm still not sure why my firmware appears to behave differently from the original RRP firmware, since this kind of error ought to affect both equally.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

my setbed.g


G31 Z2.57 P656
G30 P0 X60 Y0 Z0
G30 P1 X60 Y180 Z-0.2
G30 P2 X180 Y180 Z0.6
G30 P3 X180 Y20 Z0.7 S

Quote
antlvk
my setbed.g


G31 Z2.57 P656
G30 P0 X60 Y0 Z0
G30 P1 X60 Y180 Z-0.2
G30 P2 X180 Y180 Z0.6
G30 P3 X180 Y20 Z0.7 S

I think that the line G31 Z2.57 P656 should be in the config.g file and not the setbed file.

just wanna change on the go as have to run setbed.g anyway everytime i reboot.

If you have the G31 parameter setting command in setbed.g, then any Z homing you do before running setbed may be inaccurate because it may be using different G31 parameters. However, if you are running my firmware, then if you do a G32 (bed-probing) command without previously homing Z, the first probe will be taken as a homing probe. So my recommendation to you when using my firmware is not to z-home before you run setbed.g. Alternatively, home Z after executing the G31 parameter-setting command.

Note that my firmware also stores the G31 parameters in flash memory when you update them. So when you power up or reset the Duet, you will get the last values you used, unless you have just done a firmware update.

Also you should edit homez.g and homeall.g to make the z-homing point the same as the first bed probing point. If they are different, then only one of them can be at the centre of the white square. See my post 4 posts earlier in this thread, in particular items 3 and 4 in that post.

Edited 2 time(s). Last edit at 03/11/2014 09:14AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I also saw a G31 Z0.5 P something in the config.g what's that for?

Quote
antlvk
I also saw a G31 Z0.5 P something in the config.g what's that for?

That's just a default one. The intention is that you put your own values in it. But I think it explains the problem you are getting. After power up, when you do z-homing, it uses those parameters in config.g. Then you run setbed and G32, using a different set of parameters. The bed compensation calculates that all 4 corners of the bed are higher than they should be, so it "corrects" your Z values.

Try putting a G28 Z0 command (to re-home the Z axis) in setbed.g after your G31 command, before you do G32.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Is there an autoload for setbed.g ?

No, but why would you need one? You can put the four M557 commands in config.g, because they should not change between runs. If you remove the G31 command from config.g, than whatever G31 parameters you set will be remembered (if you use my firmware) between runs anyway. You just need to remember to set the G31 values again whenever you update the firmware.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].