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Author Topic: Laser position sensor and mach 3  (Read 5882 times)

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Laser position sensor and mach 3
« on: February 28, 2014, 12:44:25 PM »
All, I have an interesting problem.    I have a machine that needs to take an input from a as yet unspecified laser position sensor and use that value as feedback to control other motions in the machine.  I can see immediately how to implement all of that into mach except the laser position sensor.   

Has anyone coupled mach with a laser or other non-contact position sensor?  I had thought about the touch probe option but the part I need to read is so flexible that the touch probe could easily deform it.

thanks
Greg
Re: Laser position sensor and mach 3
« Reply #1 on: February 28, 2014, 01:40:24 PM »
Will it be a simple ON/OFF ? Thru-beam, Diffuse  or Retro Reflective ?
All it needs to do is switch 5v on and off.
Plenty folks using IR LED's, Photo transistors for optical limit/Home switches and the like.
The C3 Index from CNC4PC can be used this way also, although thru-beam.
Need to know the particular sensor to be sure, but sounds doable.
Russ
Re: Laser position sensor and mach 3
« Reply #2 on: February 28, 2014, 01:42:52 PM »
 
Has anyone coupled mach with a laser or other non-contact position sensor?
 
Greg

There's also the non-contact Inductive / Capacitive Proximity sensors many are using.

Russ
Re: Laser position sensor and mach 3
« Reply #3 on: February 28, 2014, 01:46:32 PM »
Looking more deeply, are you meaning a type of laser measuring device ? that would pass an actual dimensional value to Mach3 ?
Not sure about that one, bet there is a way though .... just above my level.

Regards,
Russ
Re: Laser position sensor and mach 3
« Reply #4 on: February 28, 2014, 01:48:39 PM »
Yes, I basically have to control a deformation of a part, so I want to pass an actual measurement back after the machine does some actions that will be used to determine the next set of actions
Re: Laser position sensor and mach 3
« Reply #5 on: January 06, 2015, 03:58:36 PM »
Let me know if you figure it out.  I have a laser distance measuring sensor that I would like to use in a digitizing/probing routine.  You will need to hook up the analog output from the sensor to an input pin on your controller board.  Most of the sensors output a voltage (0-10V) or current (0-24mA) signal.  You can use Mach3 "Brains" to convert the output to a dimension (or even a VB Script).

You can find a good source of sensore at www.automationdirect.com.  My sensor has a measurement range of 300mm (from 50 - 350) with 80 micron resolution.  Cost brand new is $630.  I found one on ebay for 250.  If all  you need is off/on sensing, there are less expensive versions.  You can also get higher resolution with shorter measuring ranges.  They have charts that show all the parameters you may need.

Offline BR549

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Re: Laser position sensor and mach 3
« Reply #6 on: January 06, 2015, 06:36:40 PM »
Jkovar unless your controller board has an analog input and does A/D conversions you cannot read that type of signal directly in Mach3.

Now if your measure device has a serial output Rs232 or Modbus then you can get the result directly through Rs232 or modbus. Mach3 supports both of those funtions.

You could also use a MODIO to process the Analog signal and talk to Mach3 through modbus . 

Years ago we did a project with a laser range finder and MACH3 we use a MODIO to do the A/D conversion and talk to Mach3. Back then the resolution of the laser device we used was not good enough for fine detail work such as non contact probing .

Just a thought, (;-) TP
Re: Laser position sensor and mach 3
« Reply #7 on: January 07, 2015, 08:53:03 AM »
Thanks BR549.

My probe does have RS232 communication channel.  My controller board also has analog input capabilities.  My challenge is how to use the digitizing wizard or plugin to drive the capture of the data.  I was thinking I could have code with a loop with a command that "mimics" the probe input signal to trigger a read.  Any suggestions on how to best set up would be appreciated.  Also, I was planning on using a "brain" to convert the 0-10V signal to a dimension based upon the Zmin Zmax set up on the sensor (mine is adjustable)  I planned on designing a screen for the needed inputs.

CNC-step sells a laser probe system for about $2,500 (see link to video below)  I am trying to duplicate this on a poor mans budget.

https://www.youtube.com/watch?v=UwwN5yyyKHs

I do appreciate your response.

Offline BR549

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Re: Laser position sensor and mach 3
« Reply #8 on: January 07, 2015, 11:21:26 AM »
OK does the Controller plugin bring back the analog  value to a mach3 DRO ?

IF so then it is very simple. Create a Gcode program to do the XY motion across the part to be scanned then at each junction of XY read the XYZ values to a save file.

Just a thought, (;-) TP
Re: Laser position sensor and mach 3
« Reply #9 on: January 08, 2015, 12:41:15 PM »
Here is how the sensor works.
You use the "teach" function to tell it the min-max range for the measurement (from 50mm - min to 350 mm - max OR 200 mm measuring range)  Shorter delta, say 100mm increases resolution.
The sensor will send a 0v to 10v signal proportionally over the measuring range.  (I was figuring on using a brain to convert to a measurement)  (user dros to set Zmin and Zmax to match sensor setting)
Converted input would then be placed in Z Dro.

I like your simple solution for writing on each XY change.  I am a complete newbie to this, so it may take me a while to figure out the proper G-code to accomplish this.

I appreciate your feedback.  I have attached data sheet for the sensor in case you are interested.  It can also send Values thru the rs232 interface, so I may test that as well and see what kind of readings I get.