Servo driver selection

I think the granite devices website is slightly misleading as the main blurb on the IONI drive says it is a full featured servo drive, but when you go into the purchase page it says that it only controls servo motors in torque mode

Gatesy wrote: I think the granite devices website is slightly misleading as the main blurb on the IONI drive says it is a full featured servo drive, but when you go into the purchase page it says that it only controls servo motors in torque mode

There are two ways to interpret this:
"IONI is a digital motor drive designed for driving AC/BLDC and DC servo motors and steppers. IONI allows controlling motors in all three operating modes: position control, velocity control and torque control (torque mode only with servo motors)."

It is possible to read it as saying that only servo motors can be controlled in torque mode, ie there is no way to do torque mode with a stepper.

Incidentally, we have been assuming that your motor have the 4-channel gray-code feedback (I think)

Do you have a motor model number to check that it isn't a serial encoder style?

Gatesy wrote: Just had a look at General Mechatronics. Again looks good and easy to install, but they seem to recommend the Granite VSD servo drive, that seems to do everything and prices start at 199 euros, but granite have replaced these drives with the Argon which is 489 euros!!!

Seems a bit strange that your replacement product is over twice the cost of what it replaces.

The Motors are Fanuc model 2-0 AC servo motors, 3 phase 8 pole, 2000rpm, 47V, 3A stall current

Ahh, then I might recommend the Pico Systems products. Our brushless PWM servo amp will drive these motors.
We have converters for both types of red cap encoders (old-style and serial) that produce the commutation the servo amps need. And, our Universal PWM Controller ties the whole thing together. 47 V and 2 A seems like these must be the smallest motors Fanuc makes.

The PWM controller is US $250 and handles up to 4 axes. If you need more, they can be daisy-chained on the same parallel port. The brushless PWM servo amps are $150 per axis, and the converters for Fanuc encoders are $150 per axis (both old and serial styles). Other than that, all you need are a PC with a parallel port and a power supply.

Jon

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.