Servo driver selection

Ah, I see what you mean about the Granite drives. Well if the IONI drives servos in all 3 modes then that brings that back into my choices. As it seems this will control the servo in all modes and output all waveforms to the servo as well

I will have to check the number written on the encoder cover. I'm quite happy to change them as like I mentioned previously I'd quite like to get away from Fanuc specific parts and use generic parts as much as possible

They certainly are small, only a small mill though. Will certainly give the PICO products some consideration, thanks

Gatesy wrote: I will have to check the number written on the encoder cover. I'm quite happy to change them as like I mentioned previously I'd quite like to get away from Fanuc specific parts and use generic parts as much as possible

The Fanuc encoders are unlikely to go wrong, and they are also likely to be very high quality.

The granite IONI drives seem to be able to provide the greatest variety of waveforms and control modes.

Is there any advantage in using velocity control mode over torque mode?

Seeing as using a dumb drive creates a proper feedback through the control and PC, are there any advantages or disadvantages in using a smart servo drive?

Gatesy wrote: Is there any advantage in using velocity control mode over torque mode?

The velocity feedback loop in the drive might run faster than the LinuxCNC feedback loop, and so give better velocity control.

The drawback is that you often need a Windows-only separate application to tune the drive, which is relatively inconvenient.

I don't know if the IONI drives have a dedicated mode for the Fanuc commutation signals. It seems a logical thing for them to offer.

If not, then the Pico system might be preferable.

The Granity software configuration tool is available as both windows and Linux versions

Cascaded control loops (PIV):
Torque / current control, update frequency 20.0 kHz
Velocity control, update frequency 2.5 kHz
Position control, update frequency 2.5 kHz

I have contacted Granite and need to let them know what my encoders are..

The numbers on the encoder casings are A860-0308-T112 And they are 2500P

Apparently this an incremental encoder

Gatesy wrote: Apparently this an incremental encoder

With the 4 commutation tracks?

I did have a look inside one a while, and I seem to remember it was like a glass disc with 4 tracks etched on to it?????

I'll have to check tomorrow to be sure

Gatesy wrote: I did have a look inside one a while, and I seem to remember it was like a glass disc with 4 tracks etched on to it?????

That sounds like the 4-track gray-code, as has been discussed.

Do these encoders give out a standard encoder output, or is it unique to Fanuc?