Advice on component selection.

NeoTech wrote:

Seems like the argon drivers is good universal ones and tad bit expensive tho i might say - but sure i will prob. not swap em out for a long time anyway.

Shipping shouldn't be too bad to you either, Granite are in Finland.

There are quite a few nice AC servo motors on eBay, but make sure you get ones with either a Resolver or a Quadrature encoder. The serial encoders on Panasonic make things unfortunately difficult.

Nobody seems to want Resolvers so resolver-feedback servos tend to go quite cheaply. But Mesa do a really nice Resolver card (7i49) so servos like this:
www.ebay.co.uk/itm/Hauser-Parker-HDX-92-...odrive-/181631944909
Might work nicely.

Just be aware that the electrical connectors can often cost more than the servo, so prefer ones you find with connectors already fitted.

NeoTech wrote:

But if i use a resolver servo, would i need the Argons then?!

You need some form of motor drive whatever you use.

I am not sure how the Argon drives do commutation.

On my specific machine I have brushless 3-phase motors with resolvers. The 7i49 converts the resolvers to a motor shaft position in HAL which is used for position feedback by LinuxCNC.

The drives I use (Mesa 8i20) take a digital current and phase-angle value from HAL and apply that to the motor. There is a HAL component that converts the shaft position to a calculated required phase angle.

(as an aside, I bought 3 servos very cheaply from eBay, then ended up having to write the 7i49 driver, the 8i20 driver and the bldc HAL component to make them work

To save me the effort, can you work out from the Argon docs how they handle brushless-motor commutation? (You will need to understand this anyway)

NeoTech wrote:

So the argons has a adapter; shop.granitedevices.com/product/38/argon-resolver-adapter.

That is remarkably inexpensive. I assume it is a set of passive devices/filters that allows the drive firmware to excite/read the resolver.
The dedicated converter chips cost £20 for the bare chip, so they clearly aren't using one of them.

Before I launch into a long explanation, do you know how brushless motors work?
I made a start on a wiki page, but never finished it:
wiki.linuxcnc.org/cgi-bin/wiki.pl?BLDC

The commutation can be done in the drive or in LinuxCNC. It is typically better to do it in the drive, just because it is faster and the drive can sense more about the motor.
If you have Argons and Argons can use resolvers then that is probably better than using the 7i49 card.
But that is something to worry about if you end up with resolver motors, and not before.

NeoTech wrote:

Good ? Bad ?

Bad

You have a thread trying to run every 25uS and at least one iteration was 125uS late....

There may be things to try to improve it.