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Author Topic: servo versus stepper drives  (Read 3294 times)

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Offline greg

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servo versus stepper drives
« on: January 04, 2007, 10:38:54 PM »
my first post. i was thinking of getting the new second lpt port setup from rogers machine. then i wondered if i could run steppers off of gecko servo drives and lower the volts and set up the encoders? would this be possible?   greg

Amnz

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Re: servo versus stepper drives
« Reply #1 on: January 04, 2007, 10:40:41 PM »
Hi Greg,
I don't think so...
Gecko stepper drives and Gecko servo drives are two different animals....
But you can mix them on a machine. Such as the X axis could be a stepper drive(running a stepper motor) and the Y axis could be a servo drive(running a brushed DC permanent magnet motor).

John (Bloy)
« Last Edit: January 04, 2007, 10:44:40 PM by Amnz »

Offline Chaoticone

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Re: servo versus stepper drives
« Reply #2 on: January 04, 2007, 10:57:49 PM »
You can run encoders on steppers as well. They make dual shaft steppers that would work good for that.

Brett
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Offline greg

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Re: servo versus stepper drives
« Reply #3 on: January 04, 2007, 11:12:23 PM »
i was wrong in asking about geckos because they say for brushed drive. would a servo brushlessdrive work with steppers? greg

Offline chad

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Re: servo versus stepper drives
« Reply #4 on: January 05, 2007, 06:59:41 PM »
no..

Steppers are steppers, servos are servos. You could home brew a true closed loop stepper system with lots of electronics exp.
Steppers are usually way behind servos in performance and speed this is also reflected in the price of steppers vs. servos. They were designed as a way to get close to servo position accuracy with out the added expense and complexity of a true closed loop system.

AC servo  (brush-less) = true closed loop - highest performance - highest cost.
DC servo (brushed) = true closed loop - high performance - medium to high cost.
Stepper = open loop - moderate performance , can loose position - low to high cost.

Now i am not trying to say that steppers are junk, I have a couple of machines with them and they do great. I am just trying to say that they are what they are. I also have a couple of machines with ac servos and they stomp the steppers. :)

There is a company that makes a encoder feedback for steppers. It doesn't provide true closed loop feedback but it will tell mach to stop if a stepper has lost position.

Chad