On 6 November 2014 21:29, Billy Huddleston <[email protected]> wrote: > Was looking into using a Step/Dir servo solution. It's possible to send the > encoder info back to linuxcnc to complete the control loop to linuxcnc. My > question is, how do you > configure Linux CNC in this case?
There are two ways. You can just configure exactly like a stepper, then either only use the encoder feedback to detect following errors, or in fact use an error output from the drives to detect that. The alternative is to configure the stepgens in velocity mode, which means that they output a step and direction signal at the _rate_ requested, not the number of steps requested. This means that the step-pulses are a digitally encoded velocity signal. (conceptually identical to +/- 10V velocity command). The drive remains configured just the same, but the HAL config is a lot more servo-like, with PID components (that need tuning) and encoder feedback. I have never used either setup, so can't comment on the pros and cons. You might also want to consider the (rather cheaper) hybrid steppers that have recently appeared. http://www.leadshine.com/producttypes.aspx?type=products&category=easy-servo-products&producttype=easy-servo-drives Available on eBay. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
