BLTouch Not Working After Firmware Update to 3.4

AlecSanchez

@infiniteloop Sorry I made a mistake yesterday regarding the caret (^)

M574 Y2 S1 P"io1.in"

is reading 0v while inactive, 3.3v while active

M574 Y2 S1 P"^io1.in"

is reading 0v while inactive, 2.97v while active

The switch is connected by two wires to GND and io.1in as shown in this picture:

infiniteloop

@alecsanchez said in BLTouch Not Working After Firmware Update to 3.4:

M574 Y2 S1 P"^io1.in"

is reading 0v while inactive, 2.97v while active

That's weird. As a NO switch, it should read something near 3V if open and 0V if closed. Instead, this one works in NC mode. Is this the same with your X endstop?

AlecSanchez

@infiniteloop Well I have both X and Y endstops wired as NC endstops

AlecSanchez

This is how I wire all of my X and Y endstops, and it was not a problem until I updated to 3.4

infiniteloop

@alecsanchez said in BLTouch Not Working After Firmware Update to 3.4:

This is how I wire all of my X and Y endstops, and it was not a problem until I updated to 3.4

No offence intended It's just that a lot of boards have been upgraded to 3.4 - admittedly, some had problems, but up to now, AFAIK never related to endstops. Your case is quite unique, so I try to figure out what hinders your BLTouch to extract. TBH, I see no way how to explain this with firmware (be it a setting, feature or bug …), that's why I concentrate on electrical effects.

My suspicion is that pulling io1.in to GND somehow causes a slight voltage drop, either on 3.3V or 5V, which in turn affects operation of the BLTouch. To follow this route, you'd have to try some things (if you want):

After X/Y are homed (but both not in their homing positions), activate the X switch instead of Y. Does this let the BLTouch deploy?
Move the BLTouch to IO_3 - does this help?
Measure the voltages on an easy accessible port (IO_8, IO_6 or IO_2) on the outmost pins (3.3 and 5V): can you observe a shift when you manually activate the Y endstop?

Prior to all this, you should remove the caret (^) from M574: it's counter-productive.

AlecSanchez

@infiniteloop I changed the output voltage to the bltouch to 3.3v and it fixed the problem. No more interference from the y endstop

Phaedrux

Was that a bltouch setting?

infiniteloop

@phaedrux said in BLTouch Not Working After Firmware Update to 3.4:

Was that a bltouch setting?

No, just another pin on the connector.

infiniteloop

@alecsanchez said in BLTouch Not Working After Firmware Update to 3.4:

I changed the output voltage to the bltouch to 3.3v and it fixed the problem. No more interference from the y endstop

Interesting: I had put my bet on interferences with the 3.3V rail. Instead, the 5V seam not to be as stable as supposed. Nevertheless: good that it works with 3.3V, although the BLTouch should be supplied with 5V

AlecSanchez

@infiniteloop @Phaedrux Just a follow-up regarding this issue. The 3.3v pin on the duet connector has been working great, but with two small nuances:

The bltouch red light is constantly blinking as if its in alarm mode, although it functions as normal
the bltouch does not retract when triggered anymore. I had to add an m402 command in all moves that require probing. It is nice when it is doing a mesh bed leveling though as it is not constantly deploying and retracting