Lathe build.

Ive been building a large type lathe now for about 9 months.

I had finished the bulk of it and have just finished getting the wiring sorted out.

The build was;
2 x 90 VDC 8amp motors (1 with a break retro fitted for Z)
double ball screw 0 back lash 1/4 inch
550mm x 280mm Z
15KW Spindle motor
Granite devices VSDE x 2
Granite VSDEPI
Smooth stepper
Mach3.
Delta VSD-B 15KW VSD



Needless to say ive been having lots of problems with random movement and the smooth stepper crashing. Ive been over the entire lathe with a SCOPE and there is 0 noise (well next to none)
It would seem mach3 and smoothstepper are just buggy.

I also have as spares 2 x control techniques 2HP 3 phase motors one with a brake but dont have a driver for these.

I was looking to change over to MESA and EMC2. Ive been a long time user of Ubuntu and debian in server environments.
Can anyone comment on Step /dir vs PWM which most MESA cards seem to support.

I was looking to goto the following....
EMC2
3x2x
2 x 8I20 so I can use my 3 phase servo motors
6I68
Also need a PWM driver for the VSD and how do I do encoder feed back.

Can anyone comment on the MESA parts required and would I be better of ditching the granite devices. Also reading the EMC hardware guide it doesnt say anything about the 8I20 cards or the 6I68 cards working?

Any help advice greatly appreciated.

With the granite servo-drive you need to do all tuning on the drive. There's probably software (win/linux?) on the granite site for that. Unless the drive is well matched to the servo/load you will have problems...

if you want to use a mesa card (e.g. 5i20) with your step/dir granite servo drives then you would wire the encoder feedback both to the granite-drive (so it can close the loop) and to the 5i20 card (so it EMC2 knows where the machine is). If the granite card has isolated I/O you don't strictly need anything more than a 5i20.

The 3X20 is supported by EMC (this includes both 3X20 motherboards, the 6I68 and 7I68)
Its probably overkill for most motion control applications however. Unless you need a lot of I.O
a 5I20 is probably sufficient.

I would retain you Granite drives and run in step+dir mode as a starting point.
This would require running the HostMot2 stepgen in velocity mode.
If this doesn't work out, the same Mesa hardware can be used with other drives
(there's even the distant possibility of running the Granite drives in SPI mode)

If your VFD takes PWM, then a simple I/O protector/breakout like the 7I42TA
will handle the step+dir outputs plus the PWM output for the VFD. If the VFD needs an analog output,
a 7I47S would be a good choice. The 7I47/7I47S will also handle differential encoder inputs
(the 7I42 will only work with single ended encoders)

The 8I20 is not currently supported by EMC but may be supported some time this year