#OXSpindleDriver
This is an update on the “OXSpindleDriver” Caper
Background:
I have proven to myself:
… the TinyG can be configured to output a linear Svalue vs PWM signal
… the RioRand motor control does not reproduce the PWM from the TinyG accurately nor linearly. The spindle runs at 6x the expected Svalue across a narrow speed range.
… running the RioRand with the 3V signal from the smoothie is marginal minor voltage variations change motor speed.
… there isn’t a better controller in this price range available in the market. If you know of one please let me know.
Options/trade-offs:
1.) Leave the controller as is and be satisfied with high speed operation using a cheat sheet to get more accurate Svalue speed settings in its narrow range.
2.) Modify the Rio Rand controller for better operation. (I did some of this, it gets ugly)
3.) Design a new controller that is focused on OX machines and spindles.
…
So I have decided to design and fab my own Spindle Driver
Are there others interested in this project or its product?
What do you think of the below design goals?
I am not a good PCB designer so I would need help if we want a PCB made available.
I will open source the design but without PCB help am unlikely to make these available as a kit or as a pre-assembled product.
I will fully document my prototype.
…
OX Spindle Design goals (no particular order):
A. Spindle driver PWM linearity error of <10% from 500-12,000 RPM
B. PWM range of 1-99% Duty Factor=Duty Cycle=Phase
D. Fused main power
E. Screw terminal connections
F. >10 amp drive @ 48vdc
G. Includes a remote PWM Driver Module connected at the TinyG.
H. Led indicators for PWM and DC voltage
I. Optical isolated input 0-5vdc
J. Motor compatibility, 400W DC, [two lead]
K. Integrated heat sync
L. Rational mounting on OX style extrusions
Optional features:
…On board motor voltage DVM. Cheap and moderately accurate tachometer by calibrating speed with motor voltage. You could tell if the motor is running roughly the programmed speed.
… Additional remote PWM generator module so a manual speed control can be connected instead of TinyG’s PWM. Could integrate this with the PWM Driver Module
…800W DC motor compatibility, [two lead]
… Integrated cooling fan (if needed)
… Local PWM override switch (motor comes full on with DC power not PWM)
- Does not include:*
…Local speed control
If interested here is a schematic of my changes to the Rio Rand controller used to prove out some improvements.