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Pin explanation

Added by markp over 7 years ago

Hey Group,

On the v0.3 board, I see the following signals: 'laser on' 'laser enable' and 'laser pwm'. What is each pin for, exactly? I could not find this information in the wiki.

Thanks


Replies (7)

RE: Pin explanation - Added by jaap over 7 years ago

Hi Mark,

The board has 4 outputs via opto-coupler:

  • Laser on: not in use right now in the firmware. Could be used for lasers that need a seperate laser on signal in the future.
  • Laser enable: this is used to turn the laser on. Without PWM, this would give you full laser power.
  • Laser PWM: this is a modulated signal that should give you the right laser power, depending on your config file and the file you are sending.
  • Exhaust enable: this could be used to turn your exhaust on/off with each laser job (not implemented in the firmware yet).

There is an error in the printboard releases 1 till 3 (all until now): Laser PWM and Exhaust enable are swapped. So you should connect Exhaust enable to get the PWM signal.
Example of the connection: http://redmine.laoslaser.org/projects/laos/wiki/HPC_July_2012_power_supply

RE: Pin explanation - Added by markp over 7 years ago

Ok, thanks. This helps.

What kind of signal does the PWM have?
My laser has a manual analog dial to set the laser power. Is the PWM signal compatible with this?

Thanks

RE: Pin explanation - Added by jaap over 7 years ago

Yes, you can use the dial in series with the pwm signal to have both manual and pwm control.

RE: Pin explanation - Added by markp over 7 years ago

Ok. That is good to know.

The dial is a potentiometer, with 3 pins connected.
The laser PWM has 2 pins.

Do you have an example on how to connect this?

RE: Pin explanation - Added by Anonymous over 7 years ago

The principle is as follows, if I understand it correctly:

laser-pwm.png View (119 KB)

RE: Pin explanation - Added by markp over 7 years ago

Ok, this is clear for me.
Just connect the PWM and pot in series.
The PWM signal goes throug the pot, where the voltage is lowered to the desired laser strength.

Just out of curiosity, at which frequency does the pwm operate?

Cheers!

RE: Pin explanation - Added by Anonymous over 7 years ago

Found it in the config file:

laser.pwm.freq 1000        ; pwm frequency [Hz]
    (1-7/7)