Glass Scale with UC400ETH

[spumco]

Then the position is closed inside the motion controller, you setup the position PID loops inside the motion controller (in the UCCNC).

Well that sounds pretty exciting. Especially as I'm planning to replace my steppers with servos right after I upgrade my mill spindle.

How would you handle the other problem you mentioned - the need for a real time controller (that isn't buffered)? Or the position is closed to the motion controller and the Windows software (UCCNC) doesn't adjust the trajectory - just the hardware controller?

[cncdrive]

It could be solved with a standalone controller where everything is calculated on the motion controller, it can't be solved on Windows and I would also not trust Linux even if they say it can have a realtime kernel an operating system like that is just too complex and the user can do things to overload it.
But then you would loose the ability to run your CAM softwares on the controller and so you win and loose the same time, I see no perfect solution.

[marndra]

Hi,

I just checked my post here and woow I'm surprised about the result. MANY THANKS FOR THAT REALLY MAKING IT TRANSPARENT !
Now it's clear, with my steppers that's abolute senseless.

But what can I do with my actual Hard- and Software to prevent the lost of steps?
I want to optimize it and want to have for sure the most precision and best system with my existing components.
What can I do?

[cncdrive]

If an open loop stepper system is sized and used properly then it will not loose steps.
You could also use a closed loop stepper system like what was mentioned in this forum thread or use servos.
Using servos not only good because they are closed loop, but servos has faster reaction/response time and they also have a so called "peak torque" which makes them even more dynamic.
However sizing servos for a machine is much more complicated than sizing steppers.

[ger21]

But what can I do with my actual Hard- and Software to prevent the lost of steps?

In a commercial application with open loop steppers, they run them at about 50% of their capabilities, so they have a lot of headroom.
So you design the system to be capable of 25%-50% more performance then you will use, and you won;t have any issues. I've had my open loop stepper machine over 10 years, and have never lost steps.

[marndra]

But what can I do with my actual Hard- and Software to prevent the lost of steps?

In a commercial application with open loop steppers, they run them at about 50% of their capabilities, so they have a lot of headroom.
So you design the system to be capable of 25%-50% more performance then you will use, and you won;t have any issues. I've had my open loop stepper machine over 10 years, and have never lost steps.

Woow, great answer ! Many thanks, that's exact what I did in at planning my hardware.
I have also an old Alu router with little steppers and have the same results, if you run it in normal conditions it's precise in their steps!

[janis93]

Is there are any progress in real time closed loop motion controller ?
I am thinking in my head to build one vmc and want to use linear scale for maximum accuracy. and for this i need dual closed loop system.
inner loop: velocity from motor rotary encoder to servo controller.
outer loop: linear encoder signal to motion controller, and if needed is compensated.

[Battwell]

Still waiting patiently for analog closed loop uccnc
Il be first customer.