Only one input to laser

[Ihrke052]

I have the awc 608 dsp which I used on my 80w laser and worked great however I am looking at trying an alternative laser (diode) and would like to use this setup however my diode driver only has one input and ground going to it. Is it possible to hook up the awc608 using only pwm and ground or ttl and ground?

I tried both options and the laser did not fire correctly. With pwm and ground the laser would start off and then when I press the test fire button it would fire but not turn off until I switched the power off. With ttl and ground it would start on and the laser would only stop firing when I pressed the test fire button (so it basically acted backwards). I'm not ruling out a grounding issue however this exact setup worked flawlessly with my 80w tube. The only changes are the wires connecting the awc608 to the diode driver. Plus I double checked my grounding tonight and it appears to be in order. Any thoughts?

Thanks!

[jgecik]

I'm having a similar issue and would appreciate some help as well. As for me, I'm running the DSP with the 40-60w laser power supply from LightObject and a fresh 45w tube. When I press the laser test fire button, the laser stays on until I turn off the machine.

I double checked all of my connections; they look fine and worked before my last tube cracked. All of my connections are per the wiring diagram here on the forums: http://lightobject.info/download/file.p ... &mode=view

Any help would be greatly appreciated.

[Tech_Marco]

@Ihrke052: sorry I can't help unless I have your laser (diode type) on hand for testing.

@jgecik: Did you connect "TH" or "TL" on the power supply? Double check it as you may reversed TH and TL where TH = level high triggering and TL is level low triggering.


Marco

[Ihrke052]

Hi Marco,

That's understandable. I guess my main question was whether or not the controller can output just through 1 signal, in this case PWM and Ground (leaving out the TTL) and still work (Not just for a diode laser but just in general). My laser input only has the 2 options, input and ground, so I do not have the option for the third input. Does this controller not work with only the 1 signal?

Thanks!

[Tech_Marco]

If you asked me then I would say that it should. But you gt to figure out whether is your power supply "Level high" or "Level Low" PWM signal for power controlling.

What I can do here is to run a test on a laser machine simply ground the TL and have PWM output signal driving the laser tube.


Marco

[Tech_Marco]

Update: I talked to the programmer and confirmed that there is output from the PWM vs Ground even though without the TTL connected.


Marco

[jgecik]

@Marco

Thanks for your response. I double-checked all my connections. My set up had TTL on the DSP hooked up to TL on the power supply. I tried hooking TTL up to TH on the supply and trying out the laser test fire button, but I got the same result (laser remains on until I cut power).

Okay, here's something interesting: The laser cuts off when I hit the "Reset" button.

I also ran a test cut (a small circle in some MDF) and after the cut finished, the laser still remains on. My wiring set up is the same as it was before my last tube broke. Nothing's changed except the tube, so I'm not sure what could be going wrong.

Also interesting, I loaded the above test cut into the machine with a speed of 10mm/s, but the machine is cutting at around 50mm/s, which is the DSP readout's default speed setting. It also seemed to be cutting at 35% power, which was the readout's default power for the test button. It cut deeper after I bumped up the power on the readout to 98%. The cut instructions seemed not to load into the DSP correctly.

[Ihrke052]

Well, I was able to figure mine out this morning, but it sounds like it might not solve jgecik's issue (sounds like they tried my solution already..). I found a small jumper on the driver for my diode that switches the input signal from High to Low and that's all it took (possibly the same as switching from TH to TL..?). I ran a small test job and it appears to be working smoothly!
Thanks for the input everyone!

[Tech_Marco]

Well, I was able to figure mine out this morning, but it sounds like it might not solve jgecik's issue (sounds like they tried my solution already..). I found a small jumper on the driver for my diode that switches the input signal from High to Low and that's all it took (possibly the same as switching from TH to TL..?). I ran a small test job and it appears to be working smoothly!
Thanks for the input everyone!

That's what I though. TH or TL is a signal output from the DSP to turn On or Off from the power supply. Usually we use "TL" which means Level Low or "0V" to energize a circuit instead of Level High (5V). There is a setting on the LaserCad allow one to switch the stage. But, since you don't use TH or TL, but the PWM, it is useless in this case.

I think your laser diode is 'negative' activated type. So, I'll reversed the PWM and Ground connection and give it a try


Marco

[jgecik]

Here's a question that might have something to do with my problem:

My laser tube had a small bit of metal wire wrapped around the cathode that led to the laser head. I removed it. Should I not have done that?

[Tech_Marco]

You shouldn't remove that wire. It is used to ground the laser tube to the water chiller

Marco

[jgecik]

Tried wrapping a wire from the cathode to the water-out portion of the tube. Still having the same "laser button sticking" problem. I'm really not seeing why this isn't working.

Thank you again for your help, Marco.