Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home
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No you're not the first to have some issues with the BLTouch 3.1. There were some issues when connected to the tool board that we are now aware of, but there have also been some cases with it not working as expected with the Duet3. It's also been reported to work fine, so further investigation is necessary.
The reason I bring up the manuals, etc is just to give us all the relevant information while we investigate.
It is certainly possible that the BLtouch is faulty. It wouldn't be the first time. Your config is correct, and you have checked the wiring, so either the BLTouch is faulty or there are some firmware issues with the 3.1 specifically. Both are possible.
I don't have further things to try other than my description of testing standalone mode and testing a new BLTouch. I've brought it to DC42s attention as well, so he may have some things to test soon.
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Sounds good, and again, thank you. I actually run a tech support team myself, so I truly appreciate how difficult and challenging this is. I'm also willing to do what ever I can to assist...as my first message said, this is an awesome product, and I can't imagine trying to do this stuff if we had to keep flashing firmware. With RR, it's easy to quickly spin a config and diagnose.
I have actually ordered a second BL Touch. It may be here in a couple of days, fingers crossed. Just FYI, my dad (I'm 56, he's 80!) is a micro-electronics guru, and even he grilled me about the risk of bad wiring / crimping. He pointed out, even with continuity, it's possible to have too much resistance, as well as other issues. So we did carefully go through the connector pins and add some solder too to ensure a guaranteed solid connection. Just worth noting, as my initial confidence based on "continuity" isn't necessarily proof that there's nothing wrong with the cabling.
I don't feel inclined to do anything about logical level, as clearly the D3 supplies 5V, and the BLT3.1 seems to work that way by default.
I'm definitely interested in the PWM width comment.
Given I have a D3, and Pi 4, there's two high performing pieces of kit here. If the timing is out at all in the communications via the BLT OUT -> io7.in then there is something worth investigating there.
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@Phaedrux and possibly for @dc42 to consider. I have a good collection of various Arduino / ESP and teensy boards here.
If you had a sketch (or link to) that might validate the BL Touch perhaps that would be a good troubleshooting / diagnostic step? I have Wemos D1 mini, which is 5V capable.
Just a thought.
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@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:
I don't feel inclined to do anything about logical level, as clearly the D3 supplies 5V, and the BLT3.1 seems to work that way by default.
Well the reason I brought it us is just to assess whether it may have been changed at some point or if the 3.1 is behaving different to the previous versions. More for DC42 to answer since he has a 3.1 probe to actually test with.
@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:
Given I have a D3, and Pi 4, there's two high performing pieces of kit here.
That's part of the complication actually since it introduces another layer of software and hardware. Hence why I asked if it would be possible for you to switch temporarily to standalone mode to test since it would help isolate the problem if it is firmware related. It's also really handy to be able to switch back and forth for cases like this. Once the SD card is prepared it's as easy to switch between standalone and SBC mode as pulling the SD card and connecting the Pi again.
@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:
Just FYI, my dad (I'm 56, he's 80!) is a micro-electronics guru, and even he grilled me about the risk of bad wiring / crimping.
You're quite lucky to have that in your back pocket. I myself feel quite lucky to have my father (86 and a master mechanic, electrician, and carpenter. Wealth of knowledge.)
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@Phaedrux
We are indeed very lucky. And it's remarkable how diverse our thinking and skills are. So I know we'll get there.Totally understand about the comms/timing.
Ah I misunderstood / skipped the standalone comment. I get your point. How would I go about that. I don't have a screen, which may be an issue in terms of user interface?
Before we try that, is there some GCODE I can execute which we think would give us an adjustment to the pulse width, or should we wait for dc42 to come back? Happy to do that.
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For what it's worth if this was on a Duet2 and older BLTouch it would most certainly be an issue with the white wire.
@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:
Before we try that, is there some GCODE I can execute which we think would give us an adjustment to the pulse width,
Not that I'm aware of.
@vistalert said in Duet3 BLTOUCH3.1 Probe deploys but doesn't trigger on Z Home:
I don't have a screen,
Well if the Pi is running as a headless device with no GUI then it would be a bit trickier to get your configs off, but since we are just testing you could just as easily create a fresh set of configs using the online config tool just to get a basic config in place to test with.
https://configtool.reprapfirmware.org/Start
I also should have mentioned that the ethernet cable would need to be connected to the Duet3 as well so that we had network access to reach the web control.
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@Phaedrux OK sounds pretty straight forward. I'll give it a shot.
Is there GCODE I can run that gets the probe current state?
Is it worth trying this? Have a shall script on the Pi that runs a loop to get the probe status, and it echos if it sees a non-zero value? I could deploy the pin and just keep tapping it repeatedly to see if I can ever get a 1000 reading or any non-zero value.
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Well in the web interface there is a probe value display but the problem with the bltouch is that it only triggers for a split second before resetting so it's hard to catch it show 1000.
The best way to test it is the dynamic test described in the test and calibrate z probe link I posted earlier.
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I have a 3.1 BL touch with Duet 3 6HC (actually, 3 of them) running RRF 3.1.1
config.g related to limits:
; Endstops M574 X1 S1 P"io1.in" ; configure active-high endstop for low end on X via pin io1.in M574 Y1 S1 P"io2.in" ; configure active-high endstop for low end on Y via pin io2.in ; Z-Probe M558 P9 C"io5.in" H5 R1 F120 T6000 A5 S0.02 B1 ; set Z probe type to bltouch and the dive height + speeds M950 S0 C"io5.out" ; create servo pin 0 for BLTouch G31 X-2 Y42 Z1 P25 ; Probe position and offset -
@Thalios thank you so much. This also appears to confirm, in conjunction with advice I received from another user group, that the BLT 3.1 doesn't require the pull up.
I have a few more tests to conduct now, and will revert back soon, to see if I can get this to work.
@Thalios - be a new comer to RR and GCODE generally. Can I please confirm your machine homes to front-left corner. Did you use mechanical or optical endstops? I have mechanical end stops on order, but currently using sensorless homing.
Does the order of M558 and M950 matter?
Did you do anything with the BLT 3.1, with reference to the comments in the documentation about having the pulse width variable, in case machines do miss the probe status? Or did you just run the BLT straight out the box.
One final question...so it's implicit that the BL touch is using PWM communication, so I am assuming the comms from the BLT back to the D3 is also PWM. It's not the case that the BLT is simply pulling io.in to HI state, is this understanding correct?
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I'm not 100% sure about the M558 vs M950 order, but that's how i have it set because i think you need to define the probe and its pin before you can create the servo for it (M950).
As far as pulse width, I have not changed anything in there.
I do believe it is PWM, but don't take my word for it.
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@Thalios re: 558/950 - makes perfect sense. Many thanks for the clarity and input.
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Not exactly. The M950 command is just defining a servo. It doesn't know the servo is used by a probe. The config tool generates the M950 first and I use it that way myself and it works.
; Endstops M574 Z1 S2 ; configure Z-probe endstop for low end on Z ; Z-Probe M950 S0 C"1.io0.out" ; create servo pin 0 for BLTouch M558 P9 C"^1.temp0" H5 F120 T6000 ; set Z probe type to bltouch and the dive height + speeds G31 P500 X0 Y0 Z2.5 ; set Z probe trigger value, offset and trigger height M557 X15:215 Y15:195 S20 ; define mesh grid -
Well there you have it!
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By the way, where are you guys located? I'm in Perth, Australia (originally from the UK). I'm just loving the fact that you're in a time zone that makes this support process so responsive.
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I'm in Canada (Quebec). I'm not tech support, just a very enthusiastic Duet lover.
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@Thalios - agreed. I love this product, and the community makes the journey very rewarding.
Sad to say, with the new config changes and moving the connector to io5, my BL touch probe is still failing to stop the bed rising when executiong G28 Z.
Also, if I execute M401, and periodically, and briefly, tap the probe with my finger, the Z sensor in DWC always shows 0. I think I have to wait now for another BL Touch 3.1 to arrive, which may only be a couple more days.
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@Thalios - actually, may I ask if you have a brief sequence that you used to test your BLT?
For example, did you HOMEX/Y then execute G30, etc?
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When testing on a new printer, I home X, then Y, then set the bed far enough to stop it manually, and do a manual G30. If the bed stops when I manually push the bl touch in, i know it's good to go.
also, did you create a deployprobe.g and retractprobe.g?
This is my homez.g.
G91 G1 Z5 F800 H2 ;_RRF3_ change S2 to H2 G90 G1 X150 Y150 F2400 ; Move head to center of bed M558 A1 F800 B0 ; Set single probing at faster feed rate G30 ; Do a single probe to home our Z axis M558 A5 F120 B1 ; Set multi probing at slower feed rate G30 ; Probe again to get a more accurate position G1 Z2 F200
