Dave wrote: > 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? > I'm upgrading a smt pick and place machine from steppers to servos so all the moves will be rapids from point to point, doesn't matter what path it takes to get to the end point as long as it gets there. It's a frankenstein machine I built with axis travels of 750mm on the X and Y, works fine, but it badly needs a speed upgrade. The machine originally had an AVR microcontroller generating steps for each axis and a windows box with a serial cable going directly to each axis sending commands to the AVR which would generate the steps to move the axis.
I've got EMC2 connected to the machine now, with the stepper drivers hooked up to the parallel port bypassing the AVR microcontrollers. The windows box is still managing the show. I've got a tclsh piped to a serial port on the linux box and the windows machine jogs, uploads gcode programs, and gets current position of the machine through the serial port connection by sending commands to emcsh. I've also got the console output of emc piped out another serial port so that (PRINT messages in the gcode will be sent out the serial port back to the windows machine so the app running there can get notifications of where in the gcode program it's at so it can update it's own gui accordingly like showing what chip is currently on the nozzle and percentage of job completion. It's a huge hack but it works. :-) > 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 > > ------------------------------------------------------------------------------ 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
