Fanuc servo drive integration

These Fanuc servo amplifiers require SIX PWM signals for each axis. If you have 5 motors on the robot (typical) then you would need THIRTY fast PWM channels to drive the 5 axes. Also, the top and bottom transistor of each pair must never be on at the same time, or it will likely blow the transistors. It might be better to just use 3 PWM generators with a pair of deadtime generators each to produce the 6 transistor drive signals. This would get into custom FPGA development.

Jon

Control blcd jon .picosystem.

Pwm bldc 8015a chino

This is interesting.

Did anything ever come of the previous effort to interface FANUC AC servo drives? What about FANUC AC spindle drives?

Quite a timely subject given the quality of the AC drives+servos and the obsolescence of the late 90s' early 00s' controllers.

Has anyone actually retrofitted just the controller on a red-cap based machine, and documented what was done?

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_jC wrote:

This is interesting.

Did anything ever come of the previous effort to interface FANUC AC servo drives? What about FANUC AC spindle drives?

Quite a timely subject given the quality of the AC drives+servos and the obsolescence of the late 90s' early 00s' controllers.

Has anyone actually retrofitted just the controller on a red-cap based machine, and documented what was done?

.

I have converters for both the first-generation Fanuc encoders and the later serial pulse coders. These give you standard quadrature plus index encoder output plus commutation signals. These could be used with a variety of well-known brand servo amplifiers such as Servo Dynamics, AMC and Copley.

I also have servo amps and controller for LinuxCNC that can be used with Fanuc motors. They go up to 150 V and 20 A peak. So, they are quite good for smaller Fanuc motors, but not really beefy enough for the largest motors.

Jon

I was hoping for a solution that replaces only the controller, and keeps as much of the magnetics cabinet intact as possible, including the existing cabling, powersupply and servo inverters.

The Controller <=> Servo inverter signaling seems quite similar to the Inverter <=> Drive signaling.

I take it from your reply that the current approach is to replace the FANUC Servo Inverters then?

https://lh3.googleusercontent.com/dIx1W-qv9hbpYImoEkqb5KXTtDGcZ4B9At5SoAGrmFo=w800-h600

Its possible with Mesa hardware but requires a few missing bits (Mesa already supports reading the Fanuc serial encoders without losing the absolute position information and has 3 phase PWM output capability)

If I had enough time (I dont) I would make a Fanuc Servo amp daughtercard, This would have a multichannel A-D for the
analog R/S current feedback signals, sets of buffers for the PWM signals (some models are differential, some single ended)
These buffers must be floated to read the drive state in fault conditions (some of the PWM signals are bidirectional so
the drive inputs PWM when running but outputs fault status when in faulted state). Ideally the daughtercard would have the proper Honda (older drives) or high density (newer drives) connectors for compatibility with existing cables

You have just described my thinking.

I envision a fairly large 'sheild' card for a SOM card that has sufficient GPIOs to cover the functionality of a FANUC 18, with the same form factor as the FANUC board and the same Honda connectors and etc.

I don't think anyone has looked at the FANUC spindle drive yet? It has a different interface than the kinematic servos. Also the FANUC I/O module protocol would need to be reverse engineered.

Quite a piece of work, but that is the (pipe) dream. MANOLOMARAVILLAS comment to this thread gave me hope that others might document concrete progress on the FANUC front.

I would need to get more spares to be able to contribute at this time. The FANUC machine I have is running good, but it is limited by its motion controller to 3 axis and is quite weak at HSM. (not deep enough look-ahead)

MANOLOMARAVILLAS please come back and tell us what you are doing.

Has any development gone into this?

I would love to know which mesa cards to use for pwm. Andy, you mentioned about a fpga card to use. What would you suggest? Will something like a 7i80DB work? together with a 7i75? I suppose I will need 30 I/O for a 5 axis machine with pwm. so my configuration for this machine can be as follows:
7i80DB => J2 => 7i75 => PWM
=> J3 => 7i75 => PWM
=> J4 => 7i77 => 7i84(SS)
=> J5 => 7i77 => 7i84(SS)

Would this hardware configuration work for the PWM red cap Fanuc servo drives?
Just to recap: I confirmed each drive has 6 PWM channels, 3-CW, 3-CCW. I need to drive 5 Axis on this machine.