Bltouch not deploy sometines it does

Tinchus

@DIY-O-Sphere I checked that a lot. Acording to manual distance from top of that pin should be 0-0.3mm, that was checked. Thing is: I tried 2 bltouch, the same problem happens with both of them. 1 of them is not new, was being used till 2 days ago in another printer and was working very good. That printer was going to be decomisioned so I took the bltouch.
I think I have solved the problem, cant say this is the reason, but I can say that I have done 30 probing test and none of them has failed so... it is solved? theory of the problem: the bltouch was mounted exactly bbelow and in the middle of the nema motor of the extruder. It was only separated by 2mm of plastic of the mounting.I measured magnetism and I could read in that area 350 micro teslas. Ambien magnetism is around 27 micro teslas. 3 cms away from that position I can read 170 micro teslas, and in actual position I can read 90 micro teslas (Im using a phoone aplication so reading are not supposed to be exact I guess). Can the strong magnetic field of the stepper motor affect the bltouch ? Im pretty sure it can.

DIY-O-Sphere

@Tinchus
Sounds plausible to me, BL-Touch does not like magnetic fields.

Tinchus

@DIY-O-Sphere , one question: bltouch seems to be ok now. But today I noticed something: the printer was on, idle state. I was on the computer entxt to it, and sudenly I saw the pin gown down without any instruction to do so, and inmediately was retracted again. Have you seen that in your setup? It worries me of course that happens during a print, since I guess that would mean at least loose steps, and also a posible damage on the pin...

jay_s_uk

@Tinchus that usually happens with interference. Running unshielded cables next to motor cables etc can do that. There were a number of users reporting a similar thing with an i3 style printer that used ribbon cables to the toolhead, although can't remember it's name now

Tinchus

Things have improved, still something is wrong. Cable is shielded. And despite onw the positioning of the bltouch is way from stepper, sudfdenly Im having the same issue: home Z and home all doesnt deploy the sensor. If I press emergency stop the pin drops as being deployes, sometimes in error state sometime like just having been deployed, more ideas? I changed the cable, I crimpred the pins again, dont know what else to do

Tinchus

@DIY-O-Sphere can you please share your homez.g file to me so I can see if there is something wrong there, and deployprobe.g and retractprobe.g files?

DIY-O-Sphere

@Tinchus
I would suggest the following additions or changes:
In config.g

; ENDSTOPS
M574 X1 S1 P"!io8.in"
M574 Y1 S1 P"!io6.in"
M574 Z1 S2                         ; configure Z-probe endstop for low end on Z

; bltouch
M950 S0 C"io7.out"               ;change S2 to S0        
M558 P9 C"io7.in" H5 F100 T3000 R0.2
G31 X-7 Y37 Z3.73 P25 ; bltouch offsets
M557 X7:193 Y18:195 S26.5:29.5      ; define mesh grid

In deployprobe.g

M280 P0 S10               ;change P2 to P0

In retractprobe.g

M280 P0 S90               ;change P2 to P0

Tinchus

@DIY-O-Sphere Thnka for the help. I did the chnages and still the same problem. Weird thing is: M402 and M401 works 100% all the times. It is just the homeall home Z routines that fail into deploying the probe randomly (fails 80% of the times or more)
It theory the voltage logic is automatic on version 3 of bltouch, I dont know if the duet3 has a 3 V logic or 5V, my huess is 5 because the only pin not conected to the bltouch is the 3V pin si I guess it is 5V? can someone confirm? I would try forcing the bltouch to use 5V logic just in case?
Im using the original bltouch, with the otiginal extension cable (80 cms long), it is already twisted so it has a noise protection, either way I wrapped metallic tape around to shield it, it is ok?
May be this cable is too long? (Still, the fact that M401 and M402 deploy and retracts the pin with no problem at all would say voltage it is not a problem)

And just to confirm: on wiring instructions on the grn pin, I have to conect in that pin2 cables: black and orange, is that ok?

gloomyandy

@Tinchus What happens if you put the M401/M402 in your homez.g? Does it still work then?

Tinchus

@gloomyandy ot sure I understand on what position in home.z you want me to put the commands.
from console, I can execute M401 and M402, and in 20 tries I will have 100% rate success
Inside home.z xactly where?

Phaedrux

@Tinchus said in Bltouch not deploy sometines it does:

Inside home.z xactly where?

Before and after the G30 where the pin needs to be deployed and retracted.

Tinchus

@Phaedrux Ok, did it. It works, but as I wrote above, behaviour is really erratic. Sometimes the probe is deployed, sometiomes is doplyed like with a 2 or 3 seconds of delay, sometimes is never deplyed.
Since the post started, I have re donde the conection crimps, I have shielded the cable, I have re donde the crimp again on the duet side conector, I have shorten the cable like -20 cms.
I have been readin a lot of post with similar problems and from there is that I have tried all these posible solutions.
The only one left could be noise? While probing there is no heater on, no fan on either.
ANother observation: leaving the printer on, just IDLE, may be after 10 minutes sometimes after 1 hs, I can hear the bltouch being deplyed and inmedaitly retracted.
I have discarded the posibility of a broken bltocuh, this one was working in the same printer.The only change was: the printer is an old, REALLY old i3 style, instead of decomision it, I though "hey, lets give it a bump, new electronics!" and I used a duet3 board I have as a spare (+sbc). But the bltocuh was connected to a ramp 1.4 arduino mega 2560 and was working really well with no problem at all.
May be there is some campatibility issue with duet? I really dont know how much is has been tested since bltocuh is also a really "old" hardware by now? Just thinking aloud.

Logic is 5V? I would like to confirm this before trying to force a 5V logic woirking mode on the blotouch

droftarts

@Tinchus said in Bltouch not deploy sometines it does:

I have re donde the conection crimps, I have shielded the cable, I have re donde the crimp again on the duet side conector, I have shorten the cable like -20 cms.

Replace the entire cable to the BLTouch. If the printer is old and well-used, and the BLTouch is as well, I expect one of the wires is frayed or broken from movement somewhere along the cable run, enough to make intermittent contact. That it works sometimes indicates it's not a compatibility issue, but a connection issue.

Ian

Tinchus

@droftarts Ok, new cable installed. looks like situation is much better now but still Im having from time to time the pin droping and then going up very quickly but not enough becuse it hits the print and the pin as bent twice... I saw in real time that: when it happened I saw the red led blink for a second. Rading and reading this could be an interference issue or problem on the 5V line, also some people installed a small capacitor between S and GRND on the bltocuh.
Thoughts?

Phaedrux

Photos of the print head and wiring run?

Tinchus

@Phaedrux Sure.

On the left there is bltouch an its connections marked as 1 and 2. Cable is new, and shielded with a metal tape. En the right is heatsing fan cable, thermistor and heater cartridge cable all together marked as 3

All cables ogether with extrudet stepper motor cable get together on top of the printhead. On the picture you see them but in reality they are all together inside a chain cable (not in the picture since I jhad to remove it in order to do test but since the chain cable is plastic, should not make any difference in fact with cable chain should be worst scenario because all cables are tigheter, still the problem exist without the chain cable.
Numer 4 is extruder cable, number 5 is BL touch cable, and on the right the heater cartridge cable and 6 is the hatsing fan cables. As seen , stepper motor cable is also shielded

On duet side I have bltocuh conection on io7, as you can see on the last part is not shielded (does it matter). Above that there is X endstop connection and next to it the Y endstop copnnection.

The cable markes as SIGNAL bed is a cable that is just like 5 cms close, it si on the pictture but it is a conection from out1 that feeds a mosfet feeding the heated bed.

And this is the metal tape I use for shielding, I guess it works because it solved the noise problem on the flat cable of the SBC in about 8 printers using duet3 on the school.

Phaedrux

That wiring is something else.

Try connecting the bltouch directly to the board with it's short leads and have it stay close to the board and away from everything else while still upright. Do a manual Z homing and start a print and see if you still have issues with the BLtouch behaving randomly.

Tinchus

@Phaedrux Can you give more specific sugestions on what oyu se as a potential wiring problem, and how you would route cables? If I use the short cable for BL, it is kind of imposible to keep other cables away since they are loner cables Right now as you can see on th pictures BL cables are tgether on the printhead bundle. I have tries to look online for cable steup and ewverything I find are cable bundles, Even if I route every cable apart, they will somehow need to close each other when they get connected to the duet.
Please advise on what potential problem you see on pictures so I can specifically fix that
Are all sure thare is no bug in actual version or if compatible is checked on latest firmware version? Today I noticed something: when pin is not deployed, and if I manually deploy iit, led on BL readcts. If I push pin up with fingers, DWC never sees the BL activation (zprobe value is always cero). If I issue an M402 pins goes up, then M401 deploys the pin and if I try to trigger it, pin is trigger but DWC nevers sees that, probe value is always cero. Then If I do a software emergency stop, the pin drops down, and if I trigger it with my fingers, goes up and gets re deployed inmediatly and I need to turn of power in order to get control again.
Thanks in advance

Tinchus

@Tinchus I have an extra observation. while trying to separate the BL cable from the resto fo the cables, electronics were off, I moved the printhead by hand and the red led of the bl touch turned on, is that ok?

Phaedrux

@Tinchus said in Bltouch not deploy sometines it does:

@Tinchus I have an extra observation. while trying to separate the BL cable from the resto fo the cables, electronics were off, I moved the printhead by hand and the red led of the bl touch turned on, is that ok?

When you move the motors by hand they behave like generators putting a voltage back into the system which will illuminate LEDs etc. If you move them fast enough you can generate enough voltage to damage the drivers, etc.