Thanks for your very through responses. I have some clarification questions:
Analog outputs is the same as DAC and analog inputs is the same as ADC? And step/dir is input to a stepper motor, right? > Yes. EMC's motion controller module simply outputs commanded position > every millisecond for each axis. Can it also do torque control (I think this is the same as velocity control)? Will it output faster than every millisecond? > Those commands go either to a software > based step/dir generator for budget systems, or to software PID loops. > The PID loops get their feedback from any input device (almost always an > encoder counter), and send their output to any output device (usually > either a DAC or a PWM generator). Let me make sure I understand: there are three cases: 1) DAC: IO card gets a digital number representing voltage from EMC. IO card uses onboard DAC to convert to voltage. Voltage comes out of card, gets amplified by external amp, then goes to motor. 2) PWM-card: IO card gets a digital number representing voltage from EMC. IO card converts to PWM signal using PWM generator. Then gets amplified somehow...? What's the difference between a PWM generator and a PWM amplifier? 3) PWM-EMC: IO card gets pwm signal from EMC, then gets amplified... I heard that linear amplifiers are "smoother" than PWM amplifiers. Thoughts? Since smoothness is important to haptics, I think I should go the DAC route. Is my reasoning reasonable or am I completely misinformed? Thanks again, Gerry ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
