Stepper with Encoder

[jcoats]

Is there a controller or software that allows using stepper motors with encoders for feedback. I picture this as a 'half step' before going to full servo systems.

I know the high-end ShopBot uses similar method with their controller.

For me, I would like to see an 'open source' solution, but a 'cost effective' one is almost as good!

[samco]

A few people have setup emc to do that.... (tripping a following error when steps are lost). The next step would be to try to slow feed down as things start to 'slip' using emc's 'adaptive feed'

some light reading
http://cnczone.com/forums/showthread.php?t=37309
http://cnczone.com/forums/showthread.php?t=43517

sam

[ger21]

You can get a board that reads encoders and will stop the machine if it's out of position from www.rogersmachine.net Works with Mach3.

Also, Gecko is currently working on a stepper drive that uses an encoder and acts like a servo. Hopefully we'll see it in the next year.

[Juka]

Originally Posted by ger21 You can get a board that reads encoders and will stop the machine if it's out of position from www.rogersmachine.net Works with Mach3. Also, Gecko is currently working on a stepper drive that uses an encoder and acts like a servo. Hopefully we'll see it in the next year.

I think, Granite Devices already have a product like that (VSD-E).
http://www.granitedevices.fi/index.p...vo-drive-vsd-e

Juka

[ger21]

No, that's not the same. That's just a drive that works with steppers and servos. The Gecko drive will be the first of it's kind.

[Juka]

Originally Posted by ger21 No, that's not the same. That's just a drive that works with steppers and servos. The Gecko drive will be the first of it's kind.

Gerry,

Please, read VSD-E manual pages 5/34 (motor support).
http://www.granitedevices.fi/assets/...d-e_manual.pdf

Video,
http://video.google.com/videoplay?docid=243227629497610619&ei=ioI5SZXcFZKw2QLpmsC0Ag&q=VSD-e&hl=fi
What you think ? :-)

Juka

[ger21]

It looks like you may be right. How come noone knows about this? However, if you look on the next page it says that some features may not be supported yet. Is this one of them?

[Juka]

Originally Posted by ger21 It looks like you may be right. How come noone knows about this? However, if you look on the next page it says that some features may not be supported yet. Is this one of them?

Gerry, I hope that Xerxes tell details to you, all...

http://www.cnczone.com/forums/granite_devices/

Juka

[123CNC]

More info on Xerxes VSD-E, from manual:

Status of stepping motor support

The stepping motor support in VSD-E firmware version 1.20 is

preliminary and intended for development use only.
Customers are recommended to wait for final stepper motor support before using VSD-E for steppers. When ready, the
upgrade will be freely downloadable from Granite Devices web site.
However, the firmware V1.20 is already able to control stepper as high pole count sinusoidal AC servo motor

(with encoder). This can be achieved by entering following configuration parameters in GDtool

[Xerxes]

Hi folks and thanks Juka!

Yes, VSD-E already does unstallable stepper control very well. In future firmware there will be great improvement in maximum speeds, though.