7i92, laser power velocity controlled

Adding an indicator light of some sort to the machine to show that the laser is on/enabled would not be difficult, and might be a very good idea. Also adding hal connections and or physical connections to disable the laser when in e-stop would be wise and not difficult.

In addition, for safety, the PWM polarity should be such that a high output from the 7I92 disables the laser (this means using active low PWM), otherwise the laser may turn on at power up or after a watchdog bite.

I got to test a few things yesterday, but first my current workflow for safety:

• I install the Laser on my machine
• I start my machine
• I load my Laser NC-code
• I put on my glasses
• I apply power to the laser
• I start the program
• I turn off the power to the laser after the program is finished or when it stops

For now that is OK for me. In short terms i will use the LED on my powersupply as an indicator, in long terms i would like to test the active low PWM like described here: active low PWM

Now to the fun part:
I tested my PWM output and velocity linearity. I engraved a rectangle and a number where number 1 is engraved with 10% velocity, number 2 is 20% velocity and so on.

Number 1 looks way too burnt, number 7 a little weak. But all in all pretty linear. This is for now more than acceptable for my application. (engraving clock-faces)

As a reference: the rectangles are 0,5mm thick. The laser burn width is about 0,15mm.