PWM will work fine as the input to your current source, you just need a capacitor to convert it to a voltage. For logic level PWM outputs the capacitor generally does not need to be large, and a larger capacitor will slow down the response time. You will have to test different values until you get the right balance of response time and filtering. Use an op-amp to buffer the output, and it will work the same way as the R-2R ladder would.
Javid ----- Original Message ----- From: "Klemen Dovrtel" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Saturday, December 01, 2007 8:13 AM Subject: [Emc-users] open loop galvanometer control >I have two open loop galvanometers ( > http://www.laserfx.com/Backstage.LaserFX.com/Systems/Pinouts/MFEdataLG.jpg > ) which i would like to use emc controlled laser show > (similar to this one: > http://elm-chan.org/works/vlp/report_e.html ). > > I will use a hardware encoder for measuring the angle > of galvanometer. I will configure hal using > hal-encoder and hal-pid. I think i will manage to do > this (i checked the etch-servo sample configuration). > > The galvanometer is current driven, so i was thinking > of using a op-amp and R-2R resistor ladder for current > source. So i need a 10 bit digital output for R-2R > resistor ladder (instead of pwm used in etch-servo > sample configuration). How can i archive this? Is this > a good solution, or should i also use PWM (i didn't > make the hardware driver yet). > > My second problem is, that I think the position signal > from emc should be modified a bit ( > hight_on_the_wall=constant*tangens(emc_output signal > ), because otherwise the "drawing" on the wall will be > stretched at the sides. How can i achieve this? > > Regards > Klemen > > > > ____________________________________________________________________________________ > Never miss a thing. Make Yahoo your home page. > http://www.yahoo.com/r/hs > > ------------------------------------------------------------------------- > SF.Net email is sponsored by: The Future of Linux Business White Paper > from Novell. From the desktop to the data center, Linux is going > mainstream. Let it simplify your IT future. > http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
