Fanuc servo drive integration

I have meant to make a breakout board with honda connectors, to investigate the protocol with an MSO, but I am elbows and assholes deep in other projects.

That is why I am particularly interested in the discoveries of others on this front.

PCW wrote: 1. Buffers the FPGA signals to full 5V 24ma levels (and also supports differential output for some Fanuc drives)
2. Has protected Schmitt trigger 5V inputs
3. Handles the bidirectional nature of the PWM lines (they return drive status bits when DRDY is not asserted)
4. Has a 2 channel per Axis simultaneous sampling A-D for reading IS and IR so FOC can be implemented
Either in the FPGA or LinuxCNC (IS and IR are analog +-4.4V FS phase currents)

This is sounding rather more involved than I had assumed. I had thought that these motors had the old 4-wire commutation output.

Older systems use the 4 wire commutation system, newer use the serial pulsecoders.
There are Fanuc PWM drives/motors using both systems. AFAIK up until the FSSB
series (serial drive interface instead of PWM), all have analog current sense
and bidirectional PWM lines so basically the same interface hardware

This is sounding rather more involved than I had assumed. I had thought that these motors had the old 4-wire commutation output.

Fanuc went to serial encoders possibly as early as 1990 or so. These encoders typically have much higher resolution than the older ones with the 4 commutation signals. Those topped out at 10,000 cycles/rev (40,000 quadrature counts/rev). The serial ones start at 32768 counts/rev, and typically are between 64K and 256K, but they also have 1 MEG count/rev. These resolutions would be impossible with quadrature output. The 1 Meg encoder would give 30 million counts/second at 1800 RPM.

Jon

Wow... This discussion is way above me... It scares the hell out of me reading it... I have no clue... I didn't expect it to be so complicated... I might just stick with what I know, but I am very interested to learn more about this. This particular machine that I'm busy with was built around 1988. It's a Victor V-center 65, and was originally built with a Fanuc 15M controller. It has 5 axis capacity, (For Jc's question above, when I say servo drive, I mean Servo amplifier) , So for now, it might save me a lot of time to rather remove these Fanuc servo's and fit analog servos, which I am familiar with. But I am keeping these drives and motors, for educational purposes, ... to educate myself. I also know these drives are very reliable and performs very well. that's why I would like to learn more about this. There's a lot of machines with these drives, but has problematic controls. So please keep this project going, I hope you will have a less complicated solution in near future, and I will by that time definitely be buying that.

Thanks to Peter and Andy, and all others for your reply.

A FANUC 15M is a little simpler than what is shown in the FANUC 20 documentation I posted.

As far as I know your 15M is based upon series A16B- hardware, while the documentation I posted was for series A20B- hardware.

Have a look at the Connection Manual for your machine. Maybe www.cncmanuals.com/pdf/73/ge-fanuc-serie...manual-hardware.html

Page 75 of that document shows separate amp (BLDC phases?) and Serial Encoder lines to the controller CPU.

It looks way easier to interface than the more modern hardware.

edit: page 82 absolute.