Won't HOME after capacitive sensor installed

Excelon

0_1545799668109_Screenshot (35).png

Thank god for auto bed leveling

Phaedrux

Your home all is a little weird since it does a fast home of x and y, then moves back a little bit and homes z, and then moves some more in x and y.

You should finish all the x and y moves first and then move the probe to the center of the bed and g30 there to get a good center point z height. Use the same coordinates for the homez for consistency.

Phaedrux

Now just missing config.g

Excelon

@phaedrux 0_1545804443527_config.g

Sorry, I missed that somehow...

Excelon

@phaedrux

How exactly would I clean up homeall? I have X and Y going out after the fast moves like you're talking about because of the Z probe hanging off the side of the bed. Please help to make this better if it can. This is only the 3rd day or so ive been on this so I have a lot to learn.

Phaedrux

@excelon said in Won't HOME after capacitive sensor installed:

@phaedrux 0_1545804443527_config.g

Sorry, I missed that somehow...

Your max speeds and acceleration for X and Y are a little low. Fine for testing but you may want to raise them up for actual prints so you're not capping the slicer. Add a zero to the ends of the current values and you're set.

For home all I'm not sure what you mean by the probe hanging off the edge. I had posted a fixed homeall above I think.

When I get back to my computer later tonight I can post a better example. In the mean time, check the setting up a Cartesian guide in the wiki, specifically the homing files section and compare what's there to what you have to see what I mean.

Phaedrux

This is what I would use for homeall.g

G91  ; relative positioning
G1 Z5 F6000 S2  ; lift Z relative to current position
G1 S1 X-235 Y-235 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 X5 Y5 F6000   ; go back a few mm
G1 S1 X-100 Y-100 F300  ; move slowly to X and Y axis endstops once more (second pass)
G90   ; absolute positioning
G1 X190 Y160 F6000   ; put probe over the centre of the bed
G30 ; probe the bed for z height
G1 X0 Y0 ; return to home position

Remove the G30 P# from config.g

Then use this to find the probe trigger height

G90   ; absolute positioning
G1 X115 Y115 F6000 ; move nozzle to center of bed
; Jog the nozzle down until it touches the bed
; if it gets to Z0 but still doesn't touch, send G92 Z10 to trick it to think it's at 10mm, and then slowly jog it down until it is touching.
; When it's touching, send G92 Z0
G30 S-1 ; do a trigger height measurement probe
The result of the trigger height will be shown in the console. Use that value in G31 Z in config.g

Now when you homez it should give you an accurate Z position. Z0 should touch the bed.

Excelon

@phaedrux said in Won't HOME after capacitive sensor installed:

G90 ; absolute positioning
G1 X115 Y115 F6000 ; move nozzle to center of bed
; Jog the nozzle down until it touches the bed
; if it gets to Z0 but still doesn't touch, send G92 Z10 to trick it to think it's at 10mm, and then slowly jog it down until it is touching.
; When it's touching, send G92 Z0
G30 S-1 ; do a trigger height measurement probe
The result of the trigger height will be shown

list itemin the console. Use that value in G31 Z in config.g

Thank you for the homeall.g!!! It's so much cleaner and a lot less movements. I am understanding the code more and more, and then it even helps more to get your version and see it in action and what I could have done.

As for the config.g code. Am I replacing the Z-probe section altogether? Current z-probe is as follows...

; Z-Probe
G29 S1
M574 Z5 S2 ; Set Z probe
M558 P5 H5 F240 T6000 I1 ; Set Z probe type to switch and the dive height + speeds
G31 P1000 X-75 Y-45 ; Set Z probe trigger value, offset and trigger height
M557 X-8:172 Y0:220 S20 ; Define mesh grid

Phaedrux

The way you have the zprobe section right now is fine, you g31 just needs a Z parameter. You et that from measuring the trigger height as described.

Excelon

@phaedrux Thats the problem, though. entering a Z height in the G31 line like you mentioned doesn't have an effect.

Phaedrux

What value do you get when you measure it with g30 s-1?

Excelon

@phaedrux
Ok, Sorry. I think I get it now. Lowering the nozzle to the bed and tricking the software to think its higher, AND THEN registering zero when it’s at its lowest point and touching the bed. Now, when entering a negative Z value on line G31 will allow it to go beyond the -0- threshold and to the squish zone where I have been killing myself to get to?

Phaedrux

Well the measured value will likely be positive because the probe is above the nozzle and should trigger before the nozzle actually touches the bed. But then it should make z0 equal z0 and 0.2 equal 0.2.

Excelon

@phaedrux I get it and it should work but I must have something off somewhere because it works and the nozzle is close to the bed and where I would want it for printing but as soon as I start the print its too high again.

These are the steps I'm taking and the results:

Homeall which is great now thanks to you.
Home Z ; which brings the probe over the center of the bed (same as homeall) but doesn't bring it back.
Once over the middle of the bed and the 5mm dive height specified I run the G30 S-1 and it bring the nozzle all the way down to the bed and Z is reading -0.37 in the Duet webserver status.
BUT....
When I intioniate a print the lowest Z goes down to in the webserver status is 0.20 which is too high.0_1545932907319_config (3).g [0_1545932923234_homeall (2).g]

Phaedrux

@excelon said in Won't HOME after capacitive sensor installed:

Home Z ; which brings the probe over the center of the bed (same as homeall) but doesn't bring it back.

You mean you are doing home all, and then homez?

Once over the middle of the bed and the 5mm dive height specified

You mean you are sending G30 S-1 while it is 5mm above the bed, or when it's touching the bed?

When you do G30 S-1 there should be a result shown in the Gcode console. What does it say?

Excelon

@phaedrux I think I got it figured out, but I am not able to change the Z height in config.g on command 31 like you said.

Yes, I am doing homeall and then homez. When I hit homez there is no return, only dive height return. Homez jogs out over the middle of the bed and lowers the nozzle until the sensor goes off and then returns +5mm Z height and stays there. From there I try and send G30 S-1 command but the sensor is still active and I get an error message stating that the probe is already active or sensing ( sorry, not by the printer at the moment ) so it wont lower the nozzle lower without manually raising it first. Then I tried what you recommended in your post about tricking Duet (G92 Z10) and I can finally lower the nozzle all the way to the bed like you mentioned. Once on the bed I run G92 Z0 and that zeros out the Z status and I raise the nozzle to the correct printing postion and note the positive number in Z status and added that to command G31 in config.g BUT..... when I go to print the nozzle is not all the way down on the bed and I now have to use babystep +/- 0.05 to raise the nozzle. If i go back into config.g and add "1mm" to command G31.... still nothing. I was under the impression that the number specified in the G31 command in config.g, whether is be -/+, is supposed to offset the Z height.

To answer your question. Yes, I was sending G30 S-1 after homez and couldn't until I manually raised the nozzle because the sensor is closed at that time ( or open, depending on type of sensor ). After I do everything you advised me of... tricking Duet to be 10mm higher and moved the nozzle to the bed, run G92 Z0, raise the nozzle to printing height, gcode console read 0.48 and that's what I entered in command G31 in config.g, but again.... still nothing. Only difference is now the nozzle in slap on the bed surface.

Phaedrux

Ok, follow these steps exactly. It sounds like you're doing extra things that aren't needed.

Home all. Don't hit home z after. This will home all the axis and return to 0,0.

Use the axis jog buttons to move the probe to the center of the bed, and lower the z axis as low as it will go.

If the nozzle touches the bed, send G92 Z0.

If it doesn't quite touch the bed, send G92 Z10 and then jog it down until it does touch the bed, and then send G92 Z0.

Now send G30 S-1. The probe should raise up on its own and then lower again until the probe triggers.

The g-code console should give you a z probe trigger height. That number will be used in G31 Z in config.g

Do you still get 0.48?

If you repeat the steps to move the nozzle to touch the bed, send G92 Z0, and then G30 S-1 a few times in a row, do you get pretty close to the same result each time?

Are you running a G29 after this to map out the bed?

Excelon

@phaedrux said in Won't HOME after capacitive sensor installed:

Ok, follow these steps exactly. It sounds like you're doing extra things that aren't needed.
Home all. Don't hit home z after. This will home all the axis and return to 0,0.
Use the axis jog buttons to move the probe to the center of the bed, and lower the z axis as low as it will go.
If the nozzle touches the bed, send G92 Z0.
If it doesn't quite touch the bed, send G92 Z10 and then jog it down until it does touch the bed, and then send G92 Z0.
Now send G30 S-1. The probe should raise up on its own and then lower again until the probe triggers.
The g-code console should give you a z probe trigger height. That number will be used in G31 Z in config.g
Do you still get 0.48?
If you repeat the steps to move the nozzle to touch the bed, send G92 Z0, and then G30 S-1 a few times in a row, do you get pretty close to the same result each time?
Are you running a G29 after this to map out the bed?

Yes, I was doing a whole lot of extra steps. I agree with you simple is better so I did exactly like you said and in that order. Same thing! Again, the nozzle is flat on the bed. Yes, I am running G29 bed comp tool, also. Here is something to note. When you told me not to raise the nozzle and run G30 S-1. I couldn't. It gave me the same error message. 0_1545972441458_Screenshot (37).png

it's saying that the probe is already triggered so I had to manually raise it and then run G30 S-1 and yes, still getting around the same .48. Here is the major thing I think is the problem but I don't know how to fix it. When I enter the offset numbers in config.g in G31 ( IE Z0.48 ) I don't see the offset while printing but I do see it while running G30 S-1. Every time I get to that point and I enter the offset, reboot the machine and run the G30 line with the Z offset ( IE Z0.48 ) and the nozzle lands so perfect I take a deep breath and say i've got it, but like I said when I start printing the nozzle is flat against the bed and forced to use baby steps to bring it up.

What gives....? I do appreate all your help and feedback. I am not the least bit upset, only trying to get to the bottom of it, here.

Eric

Phaedrux

Ok that's something of note. The error when you you try to do G30 S-1 shouldn't happen and I think it's preventing you from getting a proper trigger height measurement which may explain the poor first layer height when you start a print.

I'm not very familiar with capacitive sensors, so I'm not sure what would be causing an already triggered error at the start of a probing move. Perhaps @dc42 has an idea why that might be.

When you run G29, does it complete the mesh compensation map successfully or do you get errors there as well?

Can you post an image of the heightmap? I'm curious to see the result.

dc42

@phaedrux said in Won't HOME after capacitive sensor installed:

I'm not very familiar with capacitive sensors, so I'm not sure what would be causing an already triggered error at the start of a probing move. Perhaps @dc42 has an idea why that might be.

That error is to be expected. The sequence was:

G30 S-1
G92 Z0
G30 S-1

So the sensor wasn't raised before the second G30 S-1 was sent.

The way I recommend measuring the trigger height is at https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe?revisionid=HEAD#Section_Calibrate_the_Z_probe_trigger_height.