TLHarrell wrote:I would hope there is some sort of an alert condition prior to the safety loop being tripped. I've had a couple projects ruined due to my laser stopping in the middle of a run. Once from a USB glitch, once from the new computer going to sleep in mid-job. Give yourself time to respond to a condition.
I haven't planned everything out yet but did figure I wouldn't want it breaking the safety loop immediately. I figure I could set up a buzzer and have it give you a minute or so to respond before it breaks the loop (It would also have a ignore option).
Talking about glitches and tips for a successful build, The first time I plugged in my laser cabinet I set up mach3 so I could jog the axis around and tune the motors. I then turned the cabinet off and went and ate dinner. When I returned I flipped the cabinet on... and that is when it happened... I heard the most terrible noise of 60000V arcing and the flickering of blue and orange coming from under the laser power supply. I panicked went for the power switch but realized I don't want to be anywhere near the frame and unplugged the outlet. By the time I got it unplugged the power supply had shut itself off. At this point my heart just sank because I figured I not only just destroyed my expensive laser ps but my motor controllers, power supplies, and my laptop. I took a few seconds to figure out what happened and couldn't figure it why, but the laser ps had arced out of the high voltage connector then into the laser power supply case, the laser was not hooked up at this point in my build and the power supply was suppose to be unplugged but wasn't.
After a while I finally figure out what had happened because this shouldn't have been possible. While at dinner mach3 crashed locking up my computer, one note it looked like it was still running so it tricked me. The laser power supply was hooked up to the interface board so it was fully functional. When I returned from dinner and flipped the laser cabinet on I didn't know is that somehow the pc was sending the fire command across the parallel port and the estop was not on. The laser supply fired the laser releasing 60000V arcing out of the high voltage connector and back to the case a full 3 inches through the air. After a few seconds the power supply realized it was arching and shutdown right as I disconnected the power cord.
Luckily not only did the power supply take this hit, it works perfectly and so does all of my electronics and my computer. So I was quite lucky I was not injured in this accident.
The moral of the story: 1. Do not plug in the laser power supply before it is connected to the laser
2. Leave the estop on when you turn on the cabinet
3. Don't trust mach3 or at least make sure it is still responsive before turning the laser on
4. Oh and don't trust Chinese products to be fully up to safety spec. (I am pretty sure those connectors are not suppose to allow arching 3 times their length)