Avon 3000 Mill retrofit

Hi All, 
At some point the S-code could be used to command the spindle speed. The control sends an analog voltage to the LARRIOZ speed control card. The card reads a sensor that counts spindle revolutions and compares it to the commanded speed. The card can then switch relays, that in turn switch the contactors driving the motorized CVT transmission between spindle and spindle motor to increase/ decrease the spindle speed as required.
 
This never worked since I got the mill. I did at the time try to get it to work, but due to lack of knowledge and/ or documentation, I could not get working. I would think that the lithium battery in the Dallas non-volatile SRAM would be long gone, but I am not sure what would be stored in SRAM. I assume (While I know not to assume anything) that the firmware would live on the EPROM and the SRAM might hold parameters relating to the specific installation. Other than JP 1(Jumper), and P1 (Potentiometer) there is no other configuration or programming port on the LARRIOZ HABIKON1 board.
Although slow, I prefer this system, as I would not sacrifice low speed torque, as would be the case with using only a VFD for speed control.
I suppose it would be fairly easy with modern microcontrollers to get the system going again, but I would be happy to hear from others as to their experience or suggestions as to how I should proceed.
Regards
P
 

Hmm...

I don't think VFDs really lose that much torque at low speeds.

Maybe at really low speeds they might, but you should be fine.

However, with a gearbox, halving speed doubles torque, which is not the case with a VFD at all.

Can you find any specs on the motor that drives the CVT adjuster? Maybe even a pic. of its nameplate. I suspect something should be available for it. Using a VFD for speed control a person can gain some low end torque using closed loop speed feedback and PID, but the CVT on my Wilton mill certainly has a lot more low speed torque than I was able get with just a vfd on another project.

I see you already answered my question. That motor is powered by two contactors fwd/rev. Good enough. It also shows a spindle speed sensor with two wires. Is that perhaps some proximity sensor?

I can see possibly configuring that with hal and/or a custom hal component by using mesa card outputs to trigger the two contactors (via relays, probably).

Never mind, a misunderstanding on my end.

Normally it will only need to switch once when he selects a different speed. Google: "cvt mill belt drive"