Demystifying Spindle Sensors

20000
(at the moment I am not at quadrature, just A and Z)

In that case you might well have a problem with the speed of the opto-sensor.

Regarding the spindle speed display - isn't it supposed to read it off the sensors? The displayed value is about 1.33 ratio smaller then the actual speed. That is even for low speeds.

Trispectiv wrote: Regarding the spindle speed display - isn't it supposed to read it off the sensors? The displayed value is about 1.33 ratio smaller then the actual speed. That is even for low speeds.

How do you know that your "actual speed" measurement isn't 1.33 times too high? What are you measuring it with?

After I converted the Orac and I was trying to use it with Mach3, I was checking the inverter frequency against the spindle RPM with a tachometer (a piece of reflective was already on the backplate when I got the lathe). Now with LinuxCNC I was just checking against the know VFD frequency and expecting the known RPM. For instance, I only get up to around 1500 RPM hen I max the VFD frequency, which should mean 2000 RPM.

I assume you have set the encoder scaling correctly, and have enabled counter-mode?

The encoder velocity output is in revs per second, with a factor of 60 there and a factor of 4 for quadrature you get an overall factor of 133.333. Is that what you are seeing?