BLTouch getting triggered

pao_wikhan

ended up doing a 4pt as the middle of the bed is stopping the probing.

dc42

Try increasing the Z dive height parameter, that's H in the M558 command.

pao_wikhan

i'll try with a flat glass to see if it changes, as it might be detecting a super dent or something.
so far right now i think all is good with the 4pt.

pao_wikhan

i noticed that when i hit print another on DWC it does not do the full cycle from homing to g29 S1, it just starts to print right away.
so what i do is after printing i hit the print button on gcode files to print another one.

pao_wikhan

it seems no matter how much dive i do if the bed itself is very warped/distorted the probe will detect the irregularity.
i added glass to the bed and its all better now. able to do a 9pt-25pt on the bed.

Thanks All!

zen

Hi @pao_wikhan

Did you fix the error with probe triggering at very high position? I seem to be having very similar issue. My probe just triggers without even touching the bed.

pao_wikhan

@zen
yep. im using 1.20 firmware and i used p8 on the m558.

zen

It didn't help in my case. This entire thing is driving me crazy, it behaves randomly

dc42

@zen said in BLTouch getting triggered:

It didn't help in my case. This entire thing is driving me crazy, it behaves randomly

To use bltouch we recommend firmware 1.21 (or 2.0beta) and P9 in M558.

zen

@dc42 Yeah, exactly what I'm using. Essentially I tried everything I could.

Is it even possible that Duet is not providing enough amps on 5v rail? BLtouch is like 300mA, so I guess we should be ok here.

Phaedrux

I had a similar situation where the BLTouch would often trigger early. The reason turned out to be that the pin inside the housing was dirty from the factory. There was some sticky residue that would keep it from dropping. The solution in my case was to remove the small set screw at the top of the housing to remove the pin. I then used fine grit sand paper and 99% alcohol and water to clean the pin and the opening of the housing. After reassembly it functioned perfectly.

Even if it's not dirty, you may need to adjust the set screw to adjust the sensitivity, since it's the set screw that acts as the magnetic core to draw up the pin. A half turn one way or the other may be enough to get it tuned properly.

zen

@phaedrux I just disassembled it today, but since I haven't seen any dirt, I didn't clear it. Also I read that grub screw should be exactly 0.3mm from flange. I will set it like this tomorrow and check results.

dc42

If the bltouch triggers the moment it is deployed due to the pin not dropping fast enough, adding some Z probe recovery delay should help. It's the R parameter in the M558 command. The units are seconds, so try e.g. R0.2. Alternatively, add a G4 delay command at the end of deployprobe.g.