mach and steppers with encoders

[dertsap]

is it any help to use encoders on steppers ,to pickup on missed steps ,will mach catch the missed steps and compensate for that , or are encoders worthless waste of cash time and effort

thanks
curt

[ger21]

It can't compensate, but with the encoder board from www.rogersmachine.net , it can pause your machine when steps are lost. It's actually a macro that comes with that board that monitors the encoder position and pauses Mach if any deviation occurs. If you can program in VB, you could write your own to do the same thing.

Actual closed loop may happen in the future, but will most likely require a Gecko G100, and would probably at least a year away, if at all.

[dertsap]

thanks Ger ,
cheap enough concidering the trouble a guy can get into

[awerby]

Originally Posted by dertsap is it any help to use encoders on steppers ,to pickup on missed steps ,will mach catch the missed steps and compensate for that , or are encoders worthless waste of cash time and effort thanks curt

[I've been testing out the new Taig DSLS system, which uses encoders on the stepper motors, and I think it's a big improvement over their standard open-loop system. Missed steps under a certain amount (I think it's 20 counts) are compensated for; larger lags will shut down the machine with an error. The new system goes about twice as fast as the old one, and just that alone makes the extra price worthwhile for someone cutting soft materials which can use the extra speed. Add the security of not destroying a part due to lost steps which you may have a lot of hours into, and it seems like something worth spending a few more bucks on. In the case of the Taig, considering that the ER spindle and Mach3 are thrown in as well as a relay box for spindle on/off (and an extra I/O function), the difference isn't much at all. If you're building a system from scratch, it's going to mean more money and expense, but there are rewards, at least potentially.]

Andrew Werby
www.computersculpture.com