Spindle Step/Dir Output

[nat2157]

Does Acorn allow the spindle output to be in step and Dir as opposed to 0-10v? Can't seem to find anything in the manual on this.

[tblough]

The spindle output is variable voltage (the Acorn can also do PWM). You can use an extra axis output to drive a stepper/servo spindle with step and direction.

[Navanod]

Tom you got me curious now. I was told in an email that step/dir isnt really supported for a spindle output. This would actually simplify things if my lathe spindle which is an ac servo motor could be set up with step/dir instead of the 0-10v analog output as my ac drive is +-10v.
otherwise I will need another intermediate board which uses PWM input of 0-10.

I want to achieve ridged tapping so bi directional control is important as well as CSS

Any videos/document showing how to do this would be welcome

[tblough]

You are correct that it is NOT supported. There have been numerous threads on here with problems attempting this and a few success stories. Spend some time with the search function and a lot of time reading. This route will require a lot of work on your part with no guarantee of success - it seems to be very drive/motor dependent.

VFD powered AC synchronous motors for spindle drives are what is well documented and proven to work.

[Navanod]

Tom I think I did read every thread I found on the subject, but it was a little left floating in the air as to whats happening now as the last post mentioning that its not functioning was last year in February. There is no room at all in my lathe for a huge motor thats why Im using the Servo motor which fits. its fine though because the servo has the 10v analog control its just +-10v so i need another breakout board for that..which i was hoping to avoid.

your comment of try searching the forums wasn't really helpful

[tblough]

Good luck with your conversion. Post your results here to help the next person.

[cnckeith]

gary campbell has had the best results that i have heard of using the Leadshine AC motor drive package as a Lathe spindle servo motor as an alternative to the traditional three phase / vfd method. He says the Leadshine unit has an input that can be used to switch it from 0-10 to step and direction and vise verse. So it can be used either as a spindle motor or as a servo motor. Just requires a little macro programming on Centroid end to accomplish.

Gary says "I use LeadShine EM motors with ELP drives to drive the spindles on small wood lathes that I produce. I use them in both velocity (-10-0-10 volt) mode AND step and direction mode, switched by an input."

i would avoid the DMM route as several have tried and failed with this combination, one issue was the 0 rpm command would never result in the DMM not moving, it would always be rotating at a slow speed or dithering.

[suntravel]

Tom you got me curious now. I was told in an email that step/dir isnt really supported for a spindle output. This would actually simplify things if my lathe spindle which is an ac servo motor could be set up with step/dir instead of the 0-10v analog output as my ac drive is +-10v.
otherwise I will need another intermediate board which uses PWM input of 0-10.

I want to achieve ridged tapping so bi directional control is important as well as CSS

Any videos/document showing how to do this would be welcome

I use JMC servos in speed mode for the spindle 0-10V for the speed and one Acorn output to change direction through a input on the servo drive.

Works perfect for rigid tapping.

Should also work to switch the servo from speed to position mode and use a Acorn header to drive the servo as C-axis. Will try this out on the lathe I am building.

Uwe

[Navanod]

gary campbell has had the best results that i have heard of using the Leadshine AC motor drive package as a Lathe spindle servo motor as an alternative to the traditional three phase / vfd method. He says the Leadshine unit has an input that can be used to switch it from 0-10 to step and direction and vise verse. So it can be used either as a spindle motor or as a servo motor. Just requires a little macro programming on Centroid end to accomplish.

Gary says "I use LeadShine EM motors with ELP drives to drive the spindles on small wood lathes that I produce. I use them in both velocity (-10-0-10 volt) mode AND step and direction mode, switched by an input."

i would avoid the DMM route as several have tried and failed with this combination, one issue was the 0 rpm command would never result in the DMM not moving, it would always be rotating at a slow speed or dithering.

I have the motor already its a chinese servo but should do the job well and it might be some work to get it running but im sure it can do a great job. I just saw that the manual I have states that there is an input for changing between position and speed mode so thats a win for now. There is also modbus and this might be helpful for setting different tuning parameters based on what the machine is doing but I am yet to really understand it and will need my partners help to really test out some code.

I use JMC servos in speed mode for the spindle 0-10V for the speed and one Acorn output to change direction through a input on the servo drive.

I wish that was the case with the drive I have but as of yet I dont see a way to reverse direction without a -10v output. Still im digging into the modbus interface to see what can be done on that side

[Navanod]

" Leadshine unit has an input that can be used to switch it from 0-10 to step and direction and vise verse. So it can be used either as a spindle motor or as a servo motor. Just requires a little macro programming on Centroid end to accomplish."

Would love to have my hands on such a macro if someone has an example I think its my best bet as it will save me purchasing an additional piece of hardware to convert the 0 -10v to an -10 -+10v. This way I can use just use 0 10v just for speed control and then for ridged tapping the step/dir...