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2012 DSP Laser Issues

PostPosted: Fri Nov 18, 2011 2:21 am
by Gadroc
I've got my DSP all hooked up and so far running pretty good. I only have one small issue. If I configure the laser to fire on TL when I power down the machine the laser fires, but if I configure the laser to fire on TH the laser will fire while I have the reset button pressed. Anyone else run into these issues or suggestions to fix it?

Re: 2012 DSP Laser Issues

PostPosted: Sun Nov 20, 2011 7:01 am
by qclaser
TH TL All try one time Software also should choose to TTL signal

Re: 2012 DSP Laser Issues

PostPosted: Sun Nov 20, 2011 5:31 pm
by Gadroc
It's not a wiring issue. Macro and his engineers have replicated the issue and are working on it.

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 1:27 pm
by Gadroc
Warning to all 2012 DSP owners and potential buyers!

It looks like there is a hardware issue with these boards per this thread. When configured to TH the board will fire with full PWM power when the Reset button is depressed. You will have to wire them using TL which results in the laser firing when power is removed.

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 2:27 pm
by bdring
I have noticed that. I put my e-stop switch in the water protect circuit. I push the e-stop when I don't want the laser to fire.

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 2:29 pm
by mattrsch
Thanks for the heads up!

Could you get away with a logic inverter on TL and an AND gate watching TH and the inverted TL with the output attached to the laser power supplies TH input? That way they both have to agree to fire the laser, so if reset makes TH go high but doesn't effect TL, the laser won't fire on reset. If power off lets TL go low but doesn't make TH go high, the laser won't fire.

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 3:11 pm
by twehr
mattrsch wrote:Thanks for the heads up!

Could you get away with a logic inverter on TL and an AND gate watching TH and the inverted TL with the output attached to the laser power supplies TH input? That way they both have to agree to fire the laser, so if reset makes TH go high but doesn't effect TL, the laser won't fire on reset. If power off lets TL go low but doesn't make TH go high, the laser won't fire.


I just posted an idea on the other forum. Why not just put an inverter (alone) between the controller and the TH. When power is removed form the controller, it will still go low, but the power to the inverter will also be removed - thus it will not go high, so no firing.

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 3:49 pm
by Gadroc
Thanks Tim.

I'm looking into what it would take to do that. Does anyone have any recommendations on how to proceed with the not on the laser trigger signal?

Would a very simple NOT circuit work described here using the two resistors and a transistor?
1) http://www.electronics-tutorials.ws/logic/logic_4.html
2) http://www.kpsec.freeuk.com/trancirc.htm

Or will this application require more thought and require something like a schmitt trigger?

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 4:12 pm
by mattrsch
twehr wrote:
I just posted an idea on the other forum. Why not just put an inverter (alone) between the controller and the TH. When power is removed form the controller, it will still go low, but the power to the inverter will also be removed - thus it will not go high, so no firing.


I suppose you could do that, but then it wouldn't be over complicated!

Re: 2012 DSP Laser Issues

PostPosted: Tue Nov 29, 2011 4:15 pm
by mattrsch
Gadroc wrote:Thanks Tim.

I'm looking into what it would take to do that. Does anyone have any recommendations on how to proceed with the not on the laser trigger signal?

Would a very simple NOT circuit work described here using the two resistors and a transistor?
1) http://www.electronics-tutorials.ws/logic/logic_4.html
2) http://www.kpsec.freeuk.com/trancirc.htm

Or will this application require more thought and require something like a schmitt trigger?


I don't see any reason that wouldn't work. Do you have any op-amps laying around? you could do one of these:
Image

Just choose the same value for Rin and Rf