Encoders with steppers

[rmajor55]

Hello,

I have a question for all the smart people on here. Is there any advantage to using encoders with steppers? I was planning on using the Keling 425oz kit with thier 4030 drivers on my JGRO then later on an aluminum machine and I might be able to get some encoders quite cheaply(free). Is it necessary or even possible to hook both encoders and steppers up together?

Thanks,
Robin

[joeclaar]

Same question, different application.

I am thinking about redoing a stepper board in a quilting machine I have. It has stepper motors but no encoders. Unlike milling steel, cloth quilts change dimensions as you quilt (draw in because of the sewing). It would be nice to be able to free wheel the steppers (move the x-y platform by hand) and be able to know the exact position of the needle (my z-axis).

Thanks -- Joe

Originally Posted by rmajor55 Hello, I have a question for all the smart people on here. Is there any advantage to using encoders with steppers? I was planning on using the Keling 425oz kit with thier 4030 drivers on my JGRO then later on an aluminum machine and I might be able to get some encoders quite cheaply(free). Is it necessary or even possible to hook both encoders and steppers up together? Thanks, Robin

[Al_The_Man]

Originally Posted by joeclaar It would be nice to be able to free wheel the steppers (move the x-y platform by hand) and be able to know the exact position of the needle (my z-axis). Thanks -- Joe

It is possible and is done in a system where the loop is closed in the controller, with both steppers and servo's, The system can turn off the servo action but still record the position.
When re-enabling the servo the controller records the present position as the valid one, so as to prevent the system from jumping immediately to the original position or recording a position error.
Again, it depends on the Controller itself closing the loop.
Al.

[jcc3inc]

Gentlemen,

I attached encoders to the double ended stepper shafts on my test table setup in order to detect lost steps. My operation does not involve feedback for positioning, but rather an added encoder readout to show actual position. Since my CNC controller shows position at all times, one can compare the readout position with the CNC display (while not moving, obviously) to see if data is lost.

See attachment (I hope)

Regards,
Jack C.

[mar999]

run it as fast as it will go until stall (see if it will return to 0-0)