Problems with configuration of 3DTouch Auto Leveling Sensor

[jlamador]

Hello:

I am configuating the 3DTouch Auto Leveling Sensor in my Geeetech I3 Por B. I follow all the instructions in the manual:
http://www.geeetech.com/wiki/index.php/ ... ing_Sensor

But the problem is in the calibration. With the command M851 I have anf offset of 7.39. After this I enter M851 Z0 ; set the offset to zero. After make the G28 command, I enter the G1 Z0 command. Then the extruder go down and I need to switch off the printer for not damage the plate.


Please, could yoy help me?

Thank you,

Jose Luis

[jlamador]

Sorry, the offset when I enter M851 is -7,39, in negative.

[GAQ]

Hi Jlamador,

-7.39 sounds like a high/low number !

I've used a BL Touch since I first built my ProB - It works flawlessly.

When I installed the BL Touch, I had to make sure that when extended, the pin was lower than the nozzle tip - but when in the up position, the pin was above the nozzle... I did this with washers / spacer. Mine is only around -1.9 offset.

I've never used an M851 command. The way I set the offset is as follows...

Firstly, I manually set the offset in the printer's menu system.
I set the offset in the printer menu Under 'Control', then choose 'Motion' Nozzle offset is the first choice here.

I know my offset should be around -2.0, so I deliberately set the offset at say -3.0 - ie too much offset.
You must then 'Store' this number - Use the menu, under 'Control' scroll down to 'Store settings', click here, there's a beep and the setting is stored.

I then use Repetier to manually control my printer.
I use Repetier to 'Home' my printer.
The Z axis will drop down to the bed and as soon as the BL Touch triggers, it rises a little, then drops to re-check the position.
(If your printer ignores the command from your 3D Touch, then this is another problem all together ! )
Repetier will then take my nozzle to Z = 5.0

Since I've set the Z offset at -3.0, the nozzle will actually be lower than 5mm above the bed...
This allows me to then lower the nozzle manually in small steps until I have the correct height of nozzle above the bed as checked with a sliver of paper...

I can then read from Repetier as to where it 'Thinks' my nozzle is.
Lets say that I set the offset as -3.0 and when the nozzle is touching the paper on the bed correctly, Repetier says my nozzle is 1.25mm above the bed - then I know what the correct offset is - It will be 3.0 minus 1.25 - so I'll set the offset on the printer using the menu as before to minus 1.75.
I'll store this setting as before and re-home the printer with Repetier.

This time, when I drop the nozzle to the bed, it should read zero when the paper is being held by the nozzle correctly...
I can sometimes take a couple of attempts to get this dialled in exactly.

Try this method and let us know how you get on - If the printer does not stop going down when the pin of the 3D touch hits the bed, then there's a different problem to solve before calibrating !

Gerry

[jlamador]

Hello Gerry and Thank yo for your quick response.

The method you are telling me about is the one I want to follow. However, I get stuck in the step I was talking about in my comment.

But I will try to do what you tell me about of putting washers or spacer between the bracket and the sensor in order to be sure that the pin was above the nozzle.
Maybe this is the problem.

I will tell you.

Thank you very much.

Jose Luis

[jlamador]

Hello Gerry:

In any case in Marlin I define the Z offset to -1.4:

define X_PROBE_OFFSET_FROM_EXTRUDER 4
#define Y_PROBE_OFFSET_FROM_EXTRUDER -43
#define Z_PROBE_OFFSET_FROM_EXTRUDER -1.4

I don't know why my printer assume the offset of -7.39. Maybe I fix that somehow in the EEPROM and now I can´t change it by loading the Marlin,

Thanks

Jose Luis

[jlamador]

Hello:

I have been doing tests. I have added two washers in order to raise the sensor.
But I think the problem is that the printer considers the offset of -7.39 instead of the one I have entered in the Marlin which is -1.4.
Please, do you know how this offset can be changed? Or, Why the printer ignores the data (-1.4) that I have entered in Marlin?

Thank you.

Jose Luis

[GAQ]

Hi Jose,

The menu system allows you to set the 3D Touch Z offset.

Scroll down to 'Control' and select.
Scroll to 'Motion' and select.
The first menu option is the 3D Touch Z offset (It is on my machine ! )
Select and turn the wheel to set the required value.
IMPORTANT...
The go to 'Control' again, select.
Scroll down to 'Store settings' and select.
If you don't store the new value, the machine will not save it.

In your Marlin, you say you have these three lines

define X_PROBE_OFFSET_FROM_EXTRUDER 4
#define Y_PROBE_OFFSET_FROM_EXTRUDER -43
#define Z_PROBE_OFFSET_FROM_EXTRUDER -1.4

Why no hash before 'define X_PROBE etc ? - maybe just an error in copying them...

When I add washers on my BL Touch bracket I am making the probe lower...
I place them between my bracket and the top of the BL Touch.
I got fed up with washers and printed a small spacer.
( I've attempted to attach a photo of my BL Touch - Blurred as I'm currently printing. - You can see the red bracket (Fan duct) has a white spacer before the BL Touch)

It is important that when the probe is deployed, the probe hits the bed before the print nozzle does !
It is important that when the probe is stowed, then it is above the print nozzle.

Have you looked around the menu on the printer - Have you found the section where you can select 'Self test' for the 3D Touch ?
You can deploy the probe and stow the probe. ( You can test see the heights it moves to quite easily when it's not moving )
Select 'Reset probe' before leaving the menu.

Remember that when you use a gcode command - say M851 to set the Z probe height (Say -2.1)...
Then you must follow this with M500 to make the printer save the setting - otherwise it is forgotten !
So it would be...
M851 -2.1
M500

Gerry

BLTouch.jpg (280.43 KiB) Viewed 8388 times

[myloweslife]

Your concern is that the carriage doesn't stop when the sensor triggers.

[Raymon1d]

Your concern is that the carriage doesn't stop when the sensor triggers mycfavisit.