connecting to laser TTL

Hi,

just to make sure I understood that correctly.
I have a 7i96s and want to connect a laser module which uses a TTL signal to control it. When I connect it like shown below, the M67 command will control the intensity, right? Or do I need to configure something to make that work?

Thanks!

 

 

Well, I know what TTL & PWM means. The problem is, that TTL (in this context) only means 5V while PWM is just pulses with no indication to voltage or frequency.

The manual of the Atomstack M100 just says 5V TTL. I googled, but did not find any good indication if they meant 5V analog or PWM. Usually (YMMV) more devices work with analog than PWM, so I went that road.

If, from your experience, TTL in this context means PWM, I'll happily take that advice. If you remember, you explained to me yesterday how to flash the second PWM output. So this has already been done.

I'll look up in the manual how that needs to be wired and post it here.

Ok, so I have flashed the card with 7i96s_2pwmd which changes STEP4 to a PWM output. Then connect the STEP4- output on the mesa card with TTL on the laser controller and the same with GND on both sides.
HAL config as per this discussion:
forum.linuxcnc.org/27-driver-boards/5480...and-wiring-for-laser

 

 

That correct? Thanks.

Yes, this is correct, well done! 

This what I added to my .hal:

# invert pwm output
setp hm2_7i96s.0.pwmgen.01.out0.invert_output true

# set output type to PWM
setp hm2_7i96s.0.pwmgen.01.output-type 1 # pwm

# set scale
setp hm2_7i96s.0.pwmgen.01.scale 100 # 100%

# test - this will enable the output and should give about 1,25V
# setp hm2_7i96s.0.pwmgen.01.value 25 # pwm
setp hm2_7i96s.0.pwmgen.01.enable true

# Link PWM output to analog-out 0
net laser-power motion.analog-out-00 => hm2_7i96s.0.pwmgen.01.value

If you comment in the pwm line (and comment out 'net laser...' you permanently get 1,25V on the output.
You can also leave it as is, run lcnc and run 'M68 E0 Q25' for the same effect. 'M68 E0 Q0' to turn it off again.

Where I'm not so sure is that the output is permanently enabled and only controlled by M67/M68. I'm going to use Lightburn which uses these M-commands instead of the spindle control. Is that ok?