First Layer Height

npm1

so would both features work at the same time and is there any gcode available to show that g32 is enabled.

I know theres gcode to see if g29 is enabled.

finally is there anything wrong with the code in the config files please help.
as i don't want to send my second duet wifi back

npm1

Ok, I read this, which looks enticing.

[[language]]
Sensor offset adjustment (H parameter in bed and bed_report macro)
Note: the best way to avoide the effect of trigger height varying across the bed is to use a nozzle contact sensor such as the Smart Effector

Mechanical sensors (FSR and other switches types) have offsets which may vary with the head position, especially on delta printers. The offset shall be adjusted for each probe point.

For this purpose, it is practical to create a macro for each probe point , moving to this point: p0.g, p1.g, etc.

On delta printers, depending the sensor type, you may have more offset on the side than in center or the reverse (bed sensors like FSR have more offset in the center while effector sensors have more offset on the sides).

Bed, bed_report and p0.g to p6.g (or more) macros shall have same coordinates and be adjusted while you displace probing points, which may notably be needed if your bed surface is weared (as could occurred easily with BuildTak) or for a different usable diameter.

To test the offset, you shall :

Do at least 3 calibrations till you get consistent results.
Execute M665 and note the reported parameters to modify your configuration file.
Please note that if you use the homing macro without end switches, the height in M665 will not be used and the height shall be modified in the homedelta.g

Move to the calibration points with the P0 to P6 macros and lower the head manually atop a paper sheet till the paper sheet began to have difficulties to slide.

Repeat for all the probe points, note the values on a paper.

You shall then modify the H parameters in the bed.g file and reload this file on the SD card. Use web interface system panel (not macro panel) for that.

Values found shall be substracted to the already defined offset, meaning that if you find +0,1 and the offset is already -0,22, you shall do -0,22-(+0,1) = -0,32

If using a ‘BuildTak’ surface, you should not ‘crush’ the filament on the surface and the resulting value while the paper begins not to slide should be within – 0.1~0,12 mm , so you should subtract 0,12 to lift up the hotend, say if offset is -0,25 while the paper is sliding at exactly 0, you should set -0,36.

After adjustment of H parameters in bed.g, modify the bed_report.g with same values, then reload bed_report.g on the SD card and run the macro.

If your paper report is neat, but the results of the calibration and bed_reports shows differences, that means that your bed is not flat. What counts is the paper measure, not the calibration result, so do not cheat by modifying the H parameter to obtain a very low calibration value.

Note that all macros could be run after being loaded on the SD card, without rebooting or restarting.

can i have an example of how to allow for variations or set this up please. how would i apply this to one of the inductive probes

npm1

Hi,
So i am running through to work out the probe trigger height,

at each point there seems to be massive deviations i.e. -3.35 mm to -4.53

is there any way of factory this in for when i run g32. for various points i probe.

The probe i am using is a 5v npn pinda style of probe, its directly connected to the duet wifi with no resistors/diode... would a diode help make the probe more consistent....

Kind Regards,

PS the new forum looks wicked, i wonder if it has IRC for on the spot community support.

dc42

A diode won't help. Is the trigger height at a fixed XY location consistent?

npm1

yes the xy points are consistent no bending or sagging.

the bed aka y axis is bolted down at its tightest point.

norbs12

I've had very similar issue with my NPN capacitive probe, never got it solve. Ended up switching to an IR probe and now getting very consistent first layers. Oddly enough the capacitive probe worked perfectly on my CR-10's stock board.

dc42

@npm1 said in First Layer Height:

yes the xy points are consistent no bending or sagging.

the bed aka y axis is bolted down at its tightest point.

So what did you mean when you said "at each point there seems to be massive deviations i.e. -3.35 mm to -4.53" ? Did you mean that the trigger height varies depending on the XY coordinates where you probe? if so then you can correct for that using H parameters on the G30 command sin bed.g; but it is better and easier if you use a probe with a consistent trigger height.

T3P3Tony

@npm1 said in First Layer Height:

ps i am getting Comments cannot contain only capital letters on this forum

Yes stops people shouting

npm1

can i have an example of the h parameter being used in the g30 command

would this be a good example of the H parameter

G30 P3 X0 Y180 Z-99999 H-4

yes at one point its -4 and another probe points its minus -3

i plan to use g30 and g29 in the bed.g file

what would be better, running g30 with 5 points colaberation first or g29 first.

npm1

GOOD NEWS,

<code>
MaxReps: 4, StepErrors: 0, FreeDm: 229, MinFreeDm 205, MaxWait: 1ms, Underruns: 0, 0
Scheduled moves: 434, completed moves: 431
Bed compensation in use: mesh
Bed probe heights: -2.125 0.000 -1.756 -0.093 1.005
</code>

I set up G29 as a macro i perform once per day, then i work out whether the probe is inconsistent or not.

And G32 for every print.

my G92 Z -3.5.

fingers crossed i wouldn't need to do this again.
I would probably dial it back just to see how complicated i went i.e. throwing in g32, g29 and independant z axis.

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