On Thu, 2009-09-24 at 13:45 +0200, Sven Wesley wrote: > I'll see what I can do, I have an aftermarket parallel port though. I > decided to take the cards out from the box and make a new PID tuning, I > think it's not correct. Anyway, something is fishy. The documentation is > saying that far higher step rates should be no problem at all.
On my first pass with the Rutex controllers, I used the PC parallel port. The step rate turned out to be way too slow. I then set up a Pico USC: http://pico-systems.com/oscrc4/catalog/product_info.php?cPath=2&products_id=21 (Short URL) http://preview.alturl.com/4v6w The USC is about ten times faster (300kHz) which allowed the motors to run at their max. RPM. > BTW, SPI is not the same thing as Kirk's "dumb drivers", right? These cards > are supporting SPI communication as well. What I meant with "dumb" driver is, the drive or amplifier takes in a velocity or torque signal and outputs a high power signal that drives the motor. There is a simple relationship between the input and output, IN * gain = OUT, no PID or other kind of intelligence. Some (old) velocity amps use an analog tachometer feed back, which needs to be tuned at the amp, but I still consider these as dumb. Pico's PWM amp is an example: http://pico-systems.com/pwmservo.html or Mesa's: http://mesanet.com/pdf/motion/7i40man.pdf I believe you mentioned you are running brushless motors which would need a different driver. What is the manufacturer and model of your motors? I did think about using the SPI on my Rutex controllers, but this would have required me to write software to interface EMC2 to the Rutex, which is a little beyond my skills. This is what I have done with EMC2/SPI so far: http://www.wallacecompany.com/machine_shop/EMC2/serial_dac/ The only problem I had with encoder noise (even with differential signal drivers: http://www.wallacecompany.com/cnc_lathe/HNC/00011-1a.jpg http://focus.ti.com/lit/ds/symlink/am26c32.pdf http://focus.ti.com/lit/ds/symlink/am26c31.pdf http://usdigital.com/products/interfaces/encoder/cable-drivers/ ) was fixed by adding a filter to my VFD's (shiny silver box in this picture): http://www.wallacecompany.com/cnc_lathe/HNC/00024-1a.jpg http://www.eastek-intl.com/images/PreoSeriesER.pdf -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
