Centroid Community CNC Support Forum

I recently wrote to J Tech about their lasers. I wanted to see if they had any experience with connecting one of their lasers to an Acorn Board. Below is the response. Does anyone have experience with J Tech lasers? Is there any delay with the output signals? (See below) Any input is appreciated.

++++++++++++++++++ Email from J Tech ++++++++++++++++++
Hi Ed,

Thanks for the email and interest in our lasers. We have seen this controller before, but I have not hooked one up myself. I think you would connect to the standard output signals for the laser input. I would check though to see if there is any delay associated with these signals though. If they are standard digital outputs (5V to 24V) then you can connect direct to the laser driver board. You can then control the output on the controller with a g code command to turn the laser on and off.

Hope this helps!

Best Regards,
Jay


Jay Johnson
J Tech Photonics, Inc.
jjohnson@jtechphotonics.com
www.jtechphotonics.com
713.826.2122

From: Ed A. Swakon <ESwakon@eas-eng.com>
Sent: Wednesday, June 19, 2019 1:03 PM
To: Sales@jtechphotonics.com
Subject: Compatibility question

I run my CNC using an Acorn Board made by Centriod. (https://www.centroidcnc.com/centroid_di ... oller.html)

Do you have experience with connecting one of your 2.8 or 4.2-watt lasers (https://jtechphotonics.com/?product=3-8 ... driver-kit) to this board?

Acorn outputs are dry contact.
What fires the laser? Particular M code?

Marty

If you are going to do any variable power work (not just on and off), I would expect a PWM input to the laser. The Acorn would not be able to do that. There is the analog output for spindle speed. Possibly that could be used with some interface/conversion circuit as needed. Although looking at the specs for these lasers, it looks like they may require a pulse signal to vary the effective power.

I ended up buying an oxlasers 5W 450nm focusable blue Laser Module Laser Engraver. It has a PWM: 0-5V input. If I just want to turn on and off the laser with M code will that work? should I use the spindle analog output?

eswakon@eas-eng.com wrote: ↑Tue Jun 25, 2019 12:59 pm I ended up buying an oxlasers 5W 450nm focusable blue Laser Module Laser Engraver. It has a PWM: 0-5V input. If I just want to turn on and off the laser with M code will that work? should I use the spindle analog output?

If you are going to turn it on and off, then you can use an M code to turn a relay output on and off. Heck you could use M3 SPINFWD among others.
I would think it possible to use the Acorn spindle Analog output, with voltage dividing resistors to get 0-5VDC, you would have to check for ISOLATION issues and you would have to use the S(spindle) words and figure out what speed to call that provides what voltage/power to your laser. But for now, if you can use on/off dry contact relays, sounds doable to me.

Do document your progress with pictures and video. I am interested to see what you come up with.

Future plans for Acorn PWM are to pipe a 5 vdc PWM output to pin 14 on the DB25
and create two parameters to control the base frequency and duty cycle of the PWM to facilitate easy variable power control of Laser modules via Gcode. This is a new software feature (hardware is in place) and when available will work on all Acorn Hardware.

Keith the next upgrade sounds great.

My next issue is creating the appropriate post processor. There are several available but don't know what is best to the Acorn board. See the attached PDF. https://jtechphotonics.com/?p=3851

cnckeith wrote: ↑Wed Jun 26, 2019 10:42 am Future plans for Acorn PWM are to pipe a 5 vdc PWM output to pin 14 on the DB25
and create two parameters to control the base frequency and duty cycle of the PWM to facilitate easy variable power control of Laser modules via Gcode. This is a new software feature (hardware is in place) and when available will work on all Acorn Hardware.

Any plans to ever make something similar work for oak (or one of the addon boards)?
I'd love to add a laser to our wood routers

Any thoughts on how to get a post processor for a laser that turns on and off the laser with the m3 and m5 commands?

turning it on and off is an easy task. Getting it to burn hotter when you are going fast and not as hot when you run slow is the interesting part. I would think a plc that tapped into the step signals of the x and y would be enough info. Then turn on the laser with each step, or every ten steps, ect.... so when you go fast, there are more steps and more heat. running slow is less steps, so less heat. Machines slow down on the corners or changing direction, so it would burn the part during that time, if it's not adjusted with machine moves.