Originally Posted by
stirling
I'm posting this here because I use Gecko drives but I suppose my question is about microstepping drives generally. Hope that's ok. Also I've searched and can't see if this has been discussed before.
When a system is turned off the motors are more than likely somewhere between full steps and if the system is mechanically "tight" then presumably that's where they'll stay. So, now the system is turned back on again. The drives as far as I'm aware don't have memory so presumably as they get step signals they energise the coils through their 10 microstep sequence BUT starting as if the motors WERE on a full step position to start with. So... presumably (sorry - lots of presumablys here) until the microstepping gets back in synch with the ACTUAL position of the motor, the motors either don't move or perhaps even "jitter" a bit. Am I on the right lines here?
Reason I'm asking is because some motion controlers I've seen "save" the last coord position before shutdown and start up again there, and some don't. Seems to me those that save the position shouldn't - due to my thinking above. Right?/Wrong? - just wondering.
Thanks
Ian
Unless it's a closed loop system with absolute encoders, the system HAS to determine it's physical location by some method which means movement to establish an absolute machine location.
Phil, Still too many interests, too many projects, and not enough time!!!!!!!!
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