Roland PNC-3000 CNC Mill/Historical Data

This page documents past hardware configurations, modifications, and reverse engineering of the Roland PNC-3000 CNC Mill that are not relevant to it's current configuration, but may be useful to others who happen to be working with one of these machines.

Roland PNC-3000 in Original State

OEM Spindle

  • Spindle had proprietary collet system
    • 3/16" shank tools only
    • Collets no longer available
  • Motor
    • 100w, 120v, 50/60 Hz
    • Matsushita SSC-852AL
    • 15.000 rpm no load speed at 100% power cycle

Reverse Engineering Spindle Speed Controller

voltage between potentiometer wiper and R16 matched to "feedback" pin voltage:

  • 5.1v (lowest stable Potentiometer setting, see behavior described below) = 4,300-5,250 RPM
  • 11.4v (highest potentiometer setting)= 14,600 RPM

for any pot setting, if feedback dropped to near 0v, spindle spins at 15,000 RPM if you drop the pot setting lower while in this condition, you can get it to lower outputs, but raising the feedback voltage then raises the set point voltage (leakage? why does this happen?)

I think we can make it work assuming spindle speed feedback of 0-12v for 0-15000 RPM linear. Arduino 5v PWM can be stepped up and smoothed to 0-12v for control, with 0-12v connected to the PCB by removing the potentiometer and sending the 0-12v signal to where the wiper/center tap was connected (feeding into R16).

  • motor speed 15,000 rpm
  • pully ratios: 1:1 (high) 19:7 (low) (motor:spindle)
  • spindle speed 15,000 rpm (high), 5,526 rpm (low)
  • optical encoder disk has 8 black sections, mounted on spindle
  • encoder: 120,000 pulse/min (high) 44,210 pulse/min (low); 2,000 hz (high) 737 hz (low)

Roland Speed Controller Board:

  • Yellow - 12V Supply
  • Orange - Supply Ground
  • Red - Feedback (0-12v proportional to Spindle Speed)
  • Brown - Spindle Enable (Enable Low, Disable High)

Speed Sensor Circuit: