3D heightmap problem

Alex9779

Just for reference, here is my homeall.g:

; Relative positioning
G91

; Lift Z
G1 Z2.5 F3600

; Move towards all axes endstops (first pass)
G1 X-999 Y-999 U999 F2400 S1
; Go back a few mm
G1 X5 Y5 U-5 F3600
; Move slowly to axes endstops once more (second pass)
G1 X-999 Y-999 U999 F360 S1

; Absolute positioning
G90

; Go to first bed probe point and home the Z axis
T99
G1 X150 Y100 F3600
T-1
;G1 X150 Y100 F3600
M401

G91
G1 Z-999 S1 F3600
G1 Z3
G90

G30
M402

; Uncomment the following line to lift the nozzle after probing
;G91
;G1 Z5 F100
;G90

InSanity

I've resorted to placing a G29 S2 in my homeall.g just after the clear transformations M561. I've had the problem between prints where I'll do another G29 and everything goes red and shifted down. The G29 S2 appears to solve this issue as I always do a G28 before any print job.

My bed.g now has

G29 S2
G29
G29 S1

This was suggested by another user and appears to work. I still also have the G29 S2 and M561 in the homeall.g file.

I would love to see an official doc on G29 instead of going by what appears to work. I looked at the code and it seams to me a G29 by itself should work, if I do that however I get the Z shift issue.

Jeff

chrishamm

Can you please share your heightmap.csv so I can take a look at it?

Alex9779

@chrishamm:

Can you please share your heightmap.csv so I can take a look at it?

http://owncloud.alitecs.de/index.php/s/MkZ4TubqrwRhAY1

It is just a small map because of all the issues I face I want the sequence to be fast…

Alex9779

@(In)Sanity well another command for the same thing I assume… The adding error that each consecutive execution some amount is added is fixed if I do M561 before homing. I think I can replace that with G29 S2 to clear the compensation...

InSanity

I probe 24 points each print. I have a modded FFCP and the bed tends to move around a bit on the springs even though I have them pretty tight, Overall not too bad but I just don't trust it to stay the same. The one that kills me is the saggy gantry from it's former life with the MK10 extrudes. It's running a bowden driven E3D legends pack now.

One thing that bugs me is I can move the carriage in a negative X position to get the probe closer to the edge of the bed, however doing so just results in 0's on the map. I find that very irritating.

From a print that I just ran:

RepRapFirmware height map file v1 generated at 2017-00-10 07:09, mean error 0.03, deviation 0.06
xmin,xmax,ymin,ymax,radius,spacing,xnum,ynum
22.00,220.00,8.00,142.00,-1.00,38.00,6,4
0.118, 0.121, 0.138, 0.100, 0.040, -0.018
0.047, 0.055, 0.055, 0.030, -0.038, -0.070
0.007, 0.033, 0.055, 0.028, -0.009, -0.080
0.004, 0.026, 0.039, 0.024, -0.020, -0.047

Jeff

Alex9779

Looking at all the screens I posted it is pretty obvious. If the displayed axes are at 0,0,0 then the beginning of the rendered plane is always too far away from the origin in Y direction considering that my lowest Y value is 35…

dc42

@(In)Sanity:

One thing that bugs me is I can move the carriage in a negative X position to get the probe closer to the edge of the bed, however doing so just results in 0's on the map. I find that very irritating.

Do you have a M208 S1 X-### command in config.g to tell the firmware that the carriage can move left as far as X-### ? If you don't, it will assume that X=0 is the lower limit.

InSanity

@dc42:

@(In)Sanity:

One thing that bugs me is I can move the carriage in a negative X position to get the probe closer to the edge of the bed, however doing so just results in 0's on the map. I find that very irritating.

Do you have a M208 S1 X-### command in config.g to tell the firmware that the carriage can move left as far as X-### ? If you don't, it will assume that X=0 is the lower limit.

I do not, so many g-codes, a lifetime of learning. I'll give that a try, I'm sure it'll work by the sounds of things.

Thanks,

Jeff

InSanity

@dc42:

@(In)Sanity:

One thing that bugs me is I can move the carriage in a negative X position to get the probe closer to the edge of the bed, however doing so just results in 0's on the map. I find that very irritating.

Do you have a M208 S1 X-### command in config.g to tell the firmware that the carriage can move left as far as X-### ? If you don't, it will assume that X=0 is the lower limit.

M208 did solve the problem, I can now get within 10mm of the left edge which is close enough. The rest of the build plate I can hit each corner.

Thanks again,

Jeff