Would LIke to incorporate Laser Distance Sensor as Variable

31 Aug 2023 18:18 #279500 by kotlikm
I am not sure if anyone has done this in the past, but for I am looking for a solution to support a custom application I have for my LinuxCNC controlled 3-axis router.

I have an application, where I need to perform a drilling like operation with a tool to install a widget into a panel at a given set of X,Y coordinates. For these installs, they are going into a sheet good type material, imagine like a polystyrene foam sheet. The installation height is critical that my install tool stops at the surface of the sheet, and does not advance into the material at all. This becomes a challenge as the sheet material can have a slightly varying thickness across panel due to manufacturing tolerances.

In order to solve this, I would like to incorporate a laser distance sensor that measures each X,Y coordinate, and allows me to use the outputting value from the distance sensor as a variable to adjust the finished Z height for my installation macro. Below is the link for the sensor type that I am considering. The outputting value from this sensor is a voltage, that would need to be calibrated, which would then allow for the conversion to be performed from voltage to distance. I know I would also have to incorporate some routines to tie the end of the tool and a value from the distance sensor, but at this point, I need to figure out how to get the values in from the sensor as a variable to LCNC that I can use in macros and programs.


Has anyone seen a similar system incorporated into a LinuxCNC run machine? Would anyone have any advice on how to handle solution like this?


Please Log in or Create an account to join the conversation.

31 Aug 2023 18:53 #279506 by andypugh
It might be worth investigating a digital-ouptput sensor (though I don't know if anyone has integrated, for example, IO-Link with LinuxCNC yet. www.automation24.co.uk/laser-distance-se...c-oid200-oidlcpkg-us )

There are, however, some options for analogue input with LinuxCNC.

I think that you could use the sensor in conjunction with "external offsets" to adjust the Z axis position.


Please Log in or Create an account to join the conversation.

31 Aug 2023 20:38 #279511 by rodw
Also consider the way a cnc plasma cutter probes to find the surface on every pierce via mechanical means. Some people use an air ram to lower a seperate probe  and sometimes they have it so it encircles the tool. Setting the height  can then be done with normal tool offsets.
a touch off routine can be called at every hole position  by editing your post processor. Your challenge is how to mechanically probe a soft surface :)

Please Log in or Create an account to join the conversation.

31 Aug 2023 23:51 #279523 by kotlikm
Thanks for the feedback. I have considered a mechanical foot system similar to the type you mention with the plasma cutters. I was hoping to avoid physical contact with the panel surface. I had also considered a laser switch like Andy linked, but I would like to avoid having to drive the z-axis up and down to find the surface point. 

I wonder if there is anyway to read a voltage output through a mesa board and treat it as a variable, I might reach out to them and see if they can think of any way to incorporate it. 

Please Log in or Create an account to join the conversation.

01 Sep 2023 00:19 #279525 by rodw
The most accurate way to measure analog voltage would be to use the Mesa THCAD  attached to an encoder input. 
The THCAD is a voltage to frequency converter so the frequency is scaled in HAL to a voltage (or more likely distance in your case)
You can choose 0-10v or 0-5 volt ranges on a THCAD2. I was able to see the voltage ramp up over 0.04mm as the probe contacted the plate in a 24 volt circuit. refer to ohmic.comp component

Please Log in or Create an account to join the conversation.

Time to create page: 0.074 seconds
Powered by Kunena Forum