Pin out direction.

Hello all,

I was unsure where to post this but i have another question I'd like to ask.

I have a laser etcher and have it hooked so I turn it on and off via a relay and at this stage a custom M code (M107/M108 for main laser power on/off, M105/M106 for laser burn/not), my issue is that when I turn everything on the relay is powered "ON" due to my BOB, but when i start LinuxCNC it flips the relay off.

Just wondering if there is a way to control this so it does not change state until told so via g-code. I have tried using a startup gcode but this did nothing as i think it is to early before it has assigned everything else, and I tried using the invert signal in the *.hal file but this seams to reset it every cycle time, i just want a "one shot" on startup if that is possible.

Hopefully this is not to difficult and that i have missed something simple, but i will keep looking unless anyone has any ideas to offer.

Thanks for reading and answering if anyone does either of those.

Will

PC's will send service data to parallel port during boot, and i am not aware of a standard for that, so the best way would be to change the pin and reboot, if it does flip > change pin and reboot again. Pretty sure some pins do not change state during boot time.

Thanks Tommylight,

Forgot to say I'm running a PCI card as well if that makes a difference.

Dam that sounds annoying as i have used all my other output pins at this point, I'll keep trying to think of a way to get round this if I can.

Might just be easier to have a manual on/off switch somewhere and have the g-code pause with a message window saying turn on maser laser power or something, I mean I need to remove the previous tool before running the laser anyway.

Anyway I will keep thinking and see what if anything I can come up with in time.

Cheers

Will

Willheg wrote:

Forgot to say I'm running a PCI card as well if that makes a difference.

It does, pins on add on cards do not change during boot, at least not on over 15 of them i used.
They remain low until LinuxCNC tells them differently.

Can you set up your BOB to use a charge pump, so that everything will be held in a known state until Linuxcnc is in control?

Alternatively, use a 5i25 instead of a PCI parallel port. It costs several times more money, but can step literally 100x faster. (and PWM faster too, possibly useful for a laser)