Dreaded "M280: Probe already triggered at start of probing move"

TomW

This has been happening for a month or so. I finally decided that a maintainence teardown was needed: disassemble linear bearings, lubricate all, replace wiring cables, etc.. I also replaced many parts of the hotend assembly.

This is a RatRig Vcore3 400mm, Duet 3 mini 5+, toolboard 1LC, raspberry pi 5 w/NVME bootup, versions are all at 3.5.3, raspberry is 12 (bookworm).

I've tried a new toolboard, a new touch probe, replaced wiring, checked connectors (pulled on/off several times to wipe), switch probe wiring from toolboard to mainboard io2. Nothing, nada, zip.

I cannot get rid of this intermitent error. BTW, yes, I played with the hex adjustment.

Please help, this has been a good machine until lately.

gloomyandy

@TomW Probably worth posting your config.g file and the details of the type of probe you are using. Seems a little odd to be getting that error with a M280 operation (which moves a servo). What sort of probe operation are you doing when this happens? If when homing Z might be worth posting your homez.g file as well.

When did this problem start to happen? Was it working ok at some point?

TomW

@gloomyandy This has been a working setup for a couple of years. I was running 3.4.3 (I don't think that I'd still was using the -rc candidate). All was well, installed the toolboard 1LC and that was working well.

Now I'm gob-smacked (as the Brits say), it stopped doing the error and I cannot force the error! This is where I've narrowed the problem down to:

M558 P9 C"20.io0.in" H5 F300 T6000 A5 R0.3 S0.02

I did not assign the "R" delay with v3.4.3, the bl touch probe worked flawlessly. Only since I had upgraded the Duet 3 Mini 5+ software that this slowly appeared more frequently (as in 1 in 20 probes of the mesh), completely at random. Sometimes it was the first probe for home (G28).

After reading the net, I added the R parameter, slowed my probe speed down, and IT DID NOT WORK. I played and played, probably a few powerups, and suddenly the M280 error went away. It's gone!

All is working and tested with a few hundred bed probes. Go figure, I ask for help and a few minutes later the problem disappears?

Notepad

@TomW Since the problem is inconsistent. I would be highly subspinous of the wiring. it could be a micro fault somewhere in the wire that is causing a short so it looks like its already active.

TomW

@Notepad All new wiring on the 1LC to BL Touch circuit (new connector ends, etc.). I even tried moving the probe back on to the mainboard:

M558 P5 C"!io2.in" H6 F240 T6000 A5 S0.03

No, I did not attempt the R-delay on the mainboard. This had been an original setup for me, io2, until I got the 1LC toolboards. I was reaching the point of getting out my pocket scope and look at the supply line noise. BTDT

I'm happy that the error went away, suddenly. The only other time I've seen this was while working at a company next to a laser crystal manufacture (read: elecric furnaces). End of the month, our development computers, mysterously, stopped working (no bootup). Doh! Took us a while to figure that out.