Problem With BLTouch Sensor

I have recently built a Hictop 3D printer:

[www.amazon.co.uk]

All working fine. Have tried to add a BLTouch sensor but have run into difficulty.

Have replaced the main control board with an MKS 1.4:

[www.amazon.co.uk]

Wired according to instructions:

[talmcmahon.com]

Having recompiled and uploaded laterst Marlin v1.1 the BLTest menu option causes the BLTouch to pulse several times. It starts up with a self-test, so I suspect the hardware config is broadly okay.

However I can't get it to trigger/deploy when homing. Have tried many config settings but it never homes so I can't set my Z height (the Hictop sensor supplied works fine).

Probably a config issue which I have overlooked. My Configuration.h file is attached.

You should use M280 P0 S10 and M280 P0 S90 to verify the BL-Touch is working. If those two commands do not deploy and retract the pin, the BL-Touch is probably not connected up to Servo-0 like it is supposed to be.

Thanks for that.

Is there a way to send gcode commands to a 3D printer interactively? I have Cura and Simplify3D available but they don't appear to offer interactive options.

you can use repetier host or mattercontrol both are free and will manually control the priter via usb

Simplify3D's Machine Control Panel window has a tab labeled Communication. Once you are connected to the printer you can type any string you want at the bottom and press Send. You will see the response in the scrolling window.

Also... The LCD Panel can do things with the BL-Touch probe. So you might be able to test things that way.

Thanks all - some good info there which I am very grateful for.

I downloaded and installed Repetier host. Now Arduino is refusing to upload new firmware to the printer - it compiles fine but fails with a timeout on upload. This is new, previously I had no problem with uploading. Have removed and reinstalled Arduino thinking that would reinstall the driver, but it didn't. I can see the printers properties from the Arduino menu so I know it can communicate.

The only change was installation of Repetier host. I see the printer now shows an IP address on its menu so Repetier host has obviously tinkered with the firmware, though I didn't do more than just run Repetier host.

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kmxsoft
Thanks all - some good info there which I am very grateful for.

I downloaded and installed Repetier host. Now Arduino is refusing to upload new firmware to the printer - it compiles fine but fails with a timeout on upload. This is new, previously I had no problem with uploading. Have removed and reinstalled Arduino thinking that would reinstall the driver, but it didn't. I can see the printers properties from the Arduino menu so I know it can communicate.

The only change was installation of Repetier host. I see the printer now shows an IP address on its menu so Repetier host has obviously tinkered with the firmware, though I didn't do more than just run Repetier host.

You can't have repetier host connected to your printer at the same time you are trying to send firmware through arduino.

You must disconnect repetier host from the printer before sending from arduino.

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jaded
You can't have repetier host connected to your printer at the same time you are trying to send firmware through arduino.

You must disconnect repetier host from the printer before sending from arduino.

Aha! The old Makerbot service problem where the Makerbot software clinged onto the printer connection and required disconnection as a specific step. I didn't think of that so many thanks for advising.

Everything is now nearly working. The response from the M280 commands are as expected. However the probe status remains fixed at activated - it doesn't change regardless of any instruction.

I imagine I've got a configuration issue relating to the BLTouch sensor but have so far failed to identify what the issue is. I have tried changing the options relating to ENDSTOPPULLUP_ZMIN, Z_MIN_PROBE_ENDSTOP_INVERTING, Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN, Z_MIN_PROBE_ENDSTOP but the sensing remains fixed at selected.

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kmxsoft
Everything is now nearly working. The response from the M280 commands are as expected. However the probe status remains fixed at activated - it doesn't change regardless of any instruction.

This may be OK. If you are trying to detect the probe's status with M119 you need to remember something.
The BL-Touch only puts out a 5ms or 10ms pulse when it is being triggered. it is hard to catch the pulse with a M119.

It isn't triggering. When I put the printer in homing mode, X & Y do the necessary, however the BLTouch probe on Z does not trigger so I have to power off to stop the Z crashing into the bed.

There is probably a gcode to stop the homing but I haven't looked for that yet - power cycling does what's needed.

In your config.h

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#define Z_MIN_PROBE_ENDSTOP_INVERTING true // set to true to invert the logic of the probe.

I think you need to change this to false as the bltouch is like a NC endstop and gives a 5mS +pulse when triggered

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obewan
In your config.h

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#define Z_MIN_PROBE_ENDSTOP_INVERTING true // set to true to invert the logic of the probe.

I think you need to change this to false as the bltouch is like a NC endstop and gives a 5mS +pulse when triggered

Have done and it makes no difference. The probe drops as expected but never triggers when the probe is pushed.

And to make matters more difficult... Some of the BL-Touch clones actually have an inverted signal. If you have a real BL-Touch, you can ignore this message. But if it is possible you have a knock off, you may need to invert the signal.

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Roxy
And to make matters more difficult... Some of the BL-Touch clones actually have an inverted signal. If you have a real BL-Touch, you can ignore this message. But if it is possible you have a knock off, you may need to invert the signal.

I actually have 3x bltouch sensors. The one currently in use (and not triggering) came from Antlabs several months ago. However I received 2x cheap versions from aliexpress yesterday so I'm going to give one of those a try.

I admit to feeling a little disappointed with the bltouch. It's a great idea but seems to be a bit fiddly to install and configure. And having multiple versions which clearly aren't 100% compatible with each other is somewhat concerning.

I've given up with the BLTouch and am now using a capacitive sensor instead. It works remarkably well, detecting the print surface about 4mm away.

Whilst I had tried to use a capacitive sensor previously, that had failed due to it needing to touch tyhe print surace before making the detection. I have since discovered that was due to the capacitive sensor being driven with a low 5v supply. When I changed that to 24v it started working as required.

Sorry but I've only just seen this - I've not had a problem with BL Touch & Marlin with the 1.x.x branches BUT I have had problems with the voltage.

For me, anything below 4.9v on the 5v rail it was very intermittent to deploying and generally behaving. Since changing electronics (and happened to get a better 5v rail) it has been working consistent (can't say accurately as I think I could have a mechanics issue there).

Just saw this.

I have 3 BLTouch in use. Very happy with their performance. I'm using MKS 1.5 running marling 1.1.x RC8. Took me FOREVER to get this configured correctly.

I'm assuming you have endstops for x/y axes as well, correct? Z homing won't happen without those.

I will share my Marlin settings. The only issue I have right now is that during bed leveling probe, Z does not go up as high as I'd like for the second touch.

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RickRap
Just saw this.

I have 3 BLTouch in use. Very happy with their performance. I'm using MKS 1.5 running marling 1.1.x RC8. Took me FOREVER to get this configured correctly.

I'm assuming you have endstops for x/y axes as well, correct? Z homing won't happen without those.

I will share my Marlin settings. The only issue I have right now is that during bed leveling probe, Z does not go up as high as I'd like for the second touch.

I have the X/Y end stops (Min only) and they work fine. It's just the Z and BLTouch that doesn't trigger.

I'm starting to believe that the board configuration might be at fault. There are multiple versions of the MKS board and I haven't found an authorative source showing the pins on the board. Marlin gives a pinm number, but where on earth is that pin on the board???

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kmxsoft
There are multiple versions of the MKS board and I haven't found an authorative source showing the pins on the board. Marlin gives a pinm number, but where on earth is that pin on the board???

Check out M43. You should be able to scan a pin number and look for it with a LED or volt meter.

I have managed to get the BLTouch probe working, nearly.

When I home all axes with a G28 X & Y do their thing, then the probe goes to mid-table. The probe deploys. Z goes down and it triggers the probe. I have double probing enabled so it rises - and then waits a couple of seconds before going down again. But it does finish.

I have configured bilinear bed levelling. When I select that with G29 it does the front 3 points okay, then moves to the next 3 where it pauses for a while - upon continuing it misses probing the middle point. Going onto the 3rd and final row it misses probing the first, and on reaching the second the display says stopped and the BLTouch probe is flashing showing an error. It never finishes the bed levelling. This behaviour is very consistent.

Problem SOLVED.

This turned out to be a multiple cause issue. Only by finally finding the correct configuration did I get the BLTouch working. These causes were:

1) Whilst I purchased the HicTop 3d board, there was a lot of confusion about which board definition this was within Marlin. The advised HicTop Marlin download worked great, but it was an earlier release which did not support the BLTouch. Their configuration defined board type 33. Which worked okay, but did not support the BLTouch. With the latest Marlin firmware I found that board type 47 was required.

2) A primary issue mentioned on this thread turned out to be the 5v supply. I finally eliminated that by fitting a 5v stabilised supply using a 24v to 5v regulator. So I have to assume that the 5v coming off the HicTop board isn't particularly stable enough to satisfy the BLTouch. I am very grateful to the person who commented about the 5v - without that comment I would never have focussed on the 5v supply.

3) The order of the contact pins is important. If connected the wrong way round then the BLTouch does not trigger. The BLTouch is not a short/open connection as you might find with a microswitch. A piece of luck solved this one - having failed to find the right configuration and with rampant frustration testing my perseverence, having given up I thought "let's change the connector pins around". And bingo - with all the other elements in place the BLTouch started triggering.

4) The Marlin configuration took a bit of figuring out as there are multiple binary choices about the probe type and its connection which have to be satisfied. I think this could be improved upon with regard to defining the BLTouch. I think HicTop could help matters by publishing a configuration guide (and a version of Marlin) defining how to use the BLTouch.

5) Using a capacitive sensor worked fairly well. However I found it was affected (badly) when the probe was getting physically cose to the PSU - as the nozzle pushed into the sprung heated bed before it triggered. I guess this must be due to magnetic fields or something. I suspect that relocating the PSU some distance away might have solved this. However that relocation wouldn't be ideal.

6) Finally compiling Marlin was taking 10-15 minutes a time, which isn't very conducive to productivity. I note this is a reported issue reported elsewhere on the Internet. I haven't fully solved this one, however it was improved markedly by configuring my anti-virus to ignore the Arduino IDE and compiler. At least my compilations are around 5 minutes now - not great but a definite improvement.

Edited 1 time(s). Last edit at 08/06/2017 07:59AM by kmxsoft.