Unable to set Z-offset, distance between nozzle and bed

[GEEKOAM]

Good afternoon,

I am using an Ender 3 chassis which has a BTT e3 RRF installed

• I have a BL touch installed and its offset is X-32.3 and Y-32.3
• I have endstop switches on X and Y and use the BL touch to Home Z
• I have a BTT TFT35 e3 installed, I am controlling from DWC

Problem

• When I start a print and G28 Runs, everything homes correctly
• when the print starts, the nozzle is far away from the bed, I can jog it down using baby steps on either the TFT or DWC, but when trying to save the Z-offset (nozzle to bed), the value is not saved and needs to be adjusted for every print

I would be shocked if all you rep rap firmware users were having to baby step on every print, that's not the case right? Even on marlin I could set the nozzle offset and get a perfect first layer every time

• How can I correctly find the nozzle to bed offset and save it so it persists between power cycles?config.g.txt
• If you are going to suggest this guide: Calibrate the Z probe trigger height(https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height), I appreciate your thoughts, but I have already followed this guide and here I am.

I have attached my Config.g and override, please let me know if you need anything else and thank you
config-override.g.txt
config.g.txt

[peter247]

@geekoam My way is to set the z offset in G31 way too high !!!
If you think it is about 1.4mm offset set it to 2mm and home and slow drop the nozzle until it drag on a peace of paper and note where it hits the paper and change to offset to match .

[GEEKOAM]

@peter247 thank you for your reply. Unfortunately I have tried this and the result seems to always bee the same, the nozzle prints too a far above the bed. I settled on setting it the way it is now using the guide I linked to.

[Phaedrux]

What's in your homeall and slicer start gocde?

[GEEKOAM]

@phaedrux
Thank you for your reply,

homeall.g
homez.g

I think that the problem may have been in the config override, I cleared all the G10 from it and now I can print a first layer.

Old override, not sure how it got this way, probably some meddling on my part

config-override.g

[GEEKOAM]

@peter247

Update

It looks as though I made some mistakes and the Overrides were messing me up. I removed them and now I am much closer to the bad, but I am about -0.29 away from where I need to be. where is the right place to enter in that The nozzle needs to be -0.29 closer to the bed after a G28?

[Phaedrux]

G10 P0 X0 Y-20 Z0 ; set tool 0 axis offsets

You only have a single nozzle, so why do you have an offset in Y? Tool0 nozzle should be considered 0,0,0

G1 X32.3 Y32.3 F10000
In your homez you should position the probe at the center of the bed for best results.

G10 L2 P1 X0.00 Y0.00 Z1.78
Not sure why that offset exists in your config-override.g. It shouldn't. Have you sent M500 at some point?

@geekoam said in Unable to set Z-offset, distance between nozzle and bed:

where is the right place to enter in that The nozzle needs to be -0.29 closer to the bed after a G28?

Adjust your G31 Z value. A higher value moves the nozzle closer to the bed after homing. A smaller value moves it farther away after homing.

So if you need to be 0.29 closer to the bed, add 0.29 to G31 Z