Yes, most low cost servo and stepper drives are interfaced via step and direction.
Up until the step and direction interface became popular the standard was a +/- 10v analog input interface and the servo drive was operated in a velocity mode or torque mode. I think that EMC2 might be the only low cost CNC software/hardware that I know of that can output a PWM signal. The drives that you have listed as "not suitable" all have the PID position loops on the drive itself. What kind of machine are you attempting to control? One of the nice things about the newest Gecko servo drive is that it will interface directly with a LPT port, even a low voltage 3.3 volt port. So depending on how you wire your machine no BOB may be required. (I have no interest in any drive or motor seller or manufacturer.) Dave Serial interface(UART,SPI),Pulse/Direction or CW/CCW,analog. On 1/7/2010 2:29 PM, Flying Electron wrote: > I'm deciding on what servo drive to use with the mesa FPGA card and it > doesn't look too bad since there are not too many low cost options. I'm > constrained to a NEMA 23 size motor since a NEMA 23 stepper is on the > machine right now and I want it to be a direct swap. So far I've found > from searching on google and from people's suggestions here on the > mailing list: > > Drives > ------- > [brushless] Pico Brushless PWM Servo Amp $150 > [brushed] Pico PWM Servo Amplifier $125 > > Motors > -------- > [brushless] Pico Size 23 Brushless Servo (61ozin continous, 180ozin > peak, 1000 CPR) $120 > [brushless] Keling KL23BLS-115 Brushless Servo (61ozin continous, 180 > ozin peak, 1000 CPR) $134 > [brushed] Keling KL23-130-60 Brushed Servo (50ozin continous, 350ozin > peak, 1000 CPR) $162 > > Not Suitable > ------------- > dmm-tech.com -- RS232 based communication not PWM > gecko -- EMC2 cannot control PID loop (step/dir input, not > pwm) > viper -- EMC2 cannot control PID loop (step/dir input, > not pwm) > rutex -- EMC2 cannot control PID loop (step/dir input, > not pwm) > > Most of the servo drives I have found have the PID loop built into > them. Is this the normal case? > > Is it possible to run a brushed DC servo with just a simple H-Bridge > controlled directly by the PWM output and a direction signal? I was > looking at the Freescale MC33886 which I think could make a very simple > and cheap H-Bridge. > http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MC33886VW-ND > <http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MC33886VW-ND> > > Anybody know of any companies or products I may have missed in my search? > > > > > ------------------------------------------------------------------------------ > This SF.Net email is sponsored by the Verizon Developer Community > Take advantage of Verizon's best-in-class app development support > A streamlined, 14 day to market process makes app distribution fast and easy > Join now and get one step closer to millions of Verizon customers > http://p.sf.net/sfu/verizon-dev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
