Plain old inductive sensor for Z height?

Corexy

@davidvh86 said in Plain old inductive sensor for Z height?:

@Corexy said in Plain old inductive sensor for Z height?:

he event my bed isn't flat I'm not so sure. I've got the IR probe on my other machine, and while the startup homing is always perfect it doesn't do a good mesh map with my Printbite surface. I was looking at going with a genuine BLTouch, but the reviews are mixed at best on that one too.
I'm really considering going to a good old fashioned inductive sensor, possibly the 12mm diameter body with the 4mm gap that seems popular.
I've just seen that Toms review video on Z probes ( https://www.youtube.com/watch?v=il9bNWn66BY ) while and I don't mind paying for a good thing, these inductive probes seemed to be right up there for performance and down there for cost...no moving parts either.
I'm using a Duet 2 wifi board. Will it run one of the 5v units directly, or should I go with the 6-36v . Will this board run a PINDA sensor correctly?
This is actually not a cost saving measure, it's more about reliable utilitarian operation. Are all these new probes that

I played with a bunch of sensors, some $80 plus and came to the conclusion a inductive sensor with a flexible steel build plate was best, always get a perfect zero. Some sensors advertise 5v compatibility but it messes with their trigger distance and accuracy. Just run it 24 and setup a voltage divider. Oh and make sure you test the output voltage with a volt meter, better safe than sorry.

Yes I'm going with a magnetic flex steel plate on a cast ally build plate, which is one of the reasons I'm asking about the inductive probe. The divider is no problem, and I'd run it at 24v myself.

Do you have a link to the probe you used?

Corexy

@fcwilt said in Plain old inductive sensor for Z height?:

Hi,

On my printers I use IR "beam break" devices for my end stop sensors.

I install them on the Z axis as well and use that for Z homing.

I am currently using BLTouch v3.0 devices for my Z probe and that is used for setting the Z=0 datum and creating the height map.

Many folks use inductive sensors for their Z probe but try to find one that does not output a voltage when inactive and pulls the output to ground when active.

I recently ordered one just to see if they can work on my printer. The silence would be preferred to the click-click of the BLTouch.

Frederick

Do you have a link to the one you ordered please?

Thank you all for your advice.

davidvh86

@Corexy

https://www.amazon.com/gp/product/B07P5CH491/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

out of stock but look for LJ18A3-8-Z/AX

If you havent got a plate yet check out ezflex

https://www.th3dstudio.com/product/ezflex2-flex-plate-smooth-or-textured-pei-coating/

Corexy

@davidvh86 said in Plain old inductive sensor for Z height?:

@Corexy

https://www.amazon.com/gp/product/B07P5CH491/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

out of stock but look for LJ18A3-8-Z/AX

If you havent got a plate yet check out ezflex

https://www.th3dstudio.com/product/ezflex2-flex-plate-smooth-or-textured-pei-coating/

Thank you.

So that's an 18mm diameter body on that one? Isn't that the one that triggers around 8mm from the bed?

Kolbi

@Corexy Do remember that when shifting build plate types - when using an inductive probe, the trigger distance can/will change. I've had good luck with the following in my config.g to rapidly setup.

; Z-Offsets - Read here: https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe   
; G31 P1000 X23 Y5 Z1.240                        ; PEI Sheet (Prusa) Offset MICRO SWISS NOZZLE	
; G31 P1000 X23 Y5 Z0.85                         ; Textured Sheet (Prusa) Offset MICRO SWISS NOZZLE
G31 P1000 X23 Y5 Z0.64                           ; Textured Sheet (thekkiinngg) Offset MICRO SWISS NOZZLE

given the trigger distance to what the sensor actually triggers against doesn't change, maybe using work offsets is a cleaner option than changing the probing?

Kolbi

@bearer Work offsets are prob the more correct option, but since it only took a few seconds to change and reset the printer with the above method, it was good enough for me at the time. But this is one of the reasons why I'm shifting to BLTouch...

fcwilt

@Kolbi said in Plain old inductive sensor for Z height?:

@bearer Work offsets are prob the more correct option, but since it only took a few seconds to change and reset the printer with the above method, it was good enough for me at the time. But this is one of the reasons why I'm shifting to BLTouch...

Hi,

I don't setup my z probe in config.g.

I have a separate macro for that that I invoke in code before setting the Z=0 datum using G30 or before creating the height map using G29.

I also have a macro button that cycles the name of a dummy fan that I am using as a mode variable. When the probe config macro executes it checks the current name of the dummy fan and changes the probe settings accordingly.

Now in my case I am changing from "consecutive readings" mode to "average readings" mode BUT it could be used in the same way to change any other setting, like the trigger height for different materials.

I don't have to edit any code, just click the macro button to select the desired mode.

Just a thought.

Frederick

Kolbi

@fcwilt Nicely done, hence your prior research into variables - makes sense now.

fcwilt

@Kolbi said in Plain old inductive sensor for Z height?:

@fcwilt Nicely done, hence your prior research into variables - makes sense now.

While dummy fans are not ideal they allow, for now, what I wanted to do.

My code is much simpler now in the sense I don't have to edit anything to change the settings, just click the macro button.

I also have a "height map mode" dummy fan that controls the creation of the height map.

Before I had 6 different macros that I had to edit in/out of code. Now I have two unchanging macros and the mode variables.

Getting true variables is only part of the job. The dummy fan names displays in DWC like any other fan so I can see the modes at a glance.

We are going to need something new in DWC to allow displaying of variables to use this approach with variables.

Frederick

Kolbi

@fcwilt It didnt even occur to me the use/display of variables in DWC. That would be way cool, especially if you could assign the variable a title in DWC and display it's contents - just as anything else. Fingers crossed

davidvh86

@Corexy
yes, the smaller bodies seem to have a closer trigger range, which might be a big deal but i wanted a good safety margin.