LinuxCNC config

Hi,

I am nearing the point with my metal lathe where I need to get electronics / PC sorted. I hope to soon have my stepper drivers sorted, then I need to look seriously at the process of configuring LinuxCNC. Last I checked, my PC for LinCNC was still booting, though I have a slight graphics issue still, so I need to be quick to drop the screen res before all goes black, after Lin started. Minor issue.

I will run my LPT inversed, giving me 5O, 12?I. I plan to output S/D for the 2 X/Z motors, I then want to control the VFD with MODBUS, I have ordered the interface.

I figured out the LPT setup, which appears quite easy, on paper. How can I set up spindle speed via MODBUS? I am planning a 3 sensor encoder on the spindle, possibly more on the axis's later on.

So far I have not found a "demo" configuration for this, on this site.

Thanks
Peet