This is a controller for a new CNC machine (photo gallery) I'm working on.

2012-03-12 - status - got the firmware "stepper simulator" working right. Holds to 1/10 degree! 4000 step/rot demo on youtube

60/120 volt DC isolated power supply for the motors. Design size: 360 watts (60v @ 6A or 120V @ 3A). Should provide the 15 VDC control power too, if it works the way I want. Hand-wound transformer, flyback design, toner transfer on single sided PCB. Based on a March 2011 Q&A article in Nuts and Volts magazine. I rewound the two small secondaries to 9 and 10 turns, as they were not quite producing enough voltage. EMI is high enough to reset the controller board though. I got a big linear transformer that works with the primary side of the supply that I'm also testing. Current status: the linear supply seems to be working OK for now, so no further power supply work is planned at the moment.

The main driver board uses an 80 MHz RX/62T microcontroller (center) and an FNB41560 three-phase driver chip (right). Interfaces include:

• FT232R usb to serial chip for programming and console (gRX compatible) or serial communications (UART1, upper left)
• E1 header for HEW compatibility (E1, upper left)
• Dual CAN interfaces (one bus, two connectors) with optional termination (top center)
• RJ45 and 8-pin header step/direction interface with limit and fault feedback (left center). Interface is TTL compatible and 5V tolerant, with 5V CMOS outputs.
• Hall/encoder interface (lower left). Complementary logic levels from the encoder are filtered and converted to LVDS (U7).
• Four limit sensors with +5, gnd, and signal connections each.
• Extra TTL serial port (UART2), can also be configured as a GPIO port. Optional +5 power via a jumper.
• U/V/W motor outputs
• +15 VDC logic and driver power (buck regulator for +5 rail)
• 15-300 VDC motor power

Full connector pinout documentation (mostly for my own reference)

The board also has an RGB status LED, current sensors for each motor phase, and motor voltage monitoring.

Note: no support whatsoever is offered for these design files; use at your own risk!

• bldc.sch - schematics, gEDA/gschem format.
• bldc-sch.pdf - schematics, PDF format.
• bldc.pcb - layout, gEDA/pcb format.
• bldc-sw.tar.gz - firmware (not inluding Renesas libraries), for GNU/Linux build environment.

Shown 2X actual size

Click image for schematic (pdf)

Shown actual size

bldc top paste gerber