Spindle feedback at high spindle speeds

frequency wrote:

The value is in a binary format with differential line drivers for each bit.

14 bits of io is rather a lot to "spend" on a spindle encoder, but it would be very easy to interface to EMC2 if you do have 14 spare input pins.

frequency wrote:

An cheap additional PCI parallel port card for the position information i think will solve my problems.
EMC then will always know the position of the spindle at low speeds and ignores it if the position is not needed at high spindle speeds!?

Configured for input, a parallel port gives you input pins. You could simply not wire the LSB, and would have 2048 resolution of the spindle.

You could wire the individual bits into the HAL "weighted sum" component to get the position back to 0-2047 numbers. You would probably need a custom component to convert the numbers to a count. (ideally stored internally as 64 bits, to prevent wrap-around problems)

One thing a bit inelegant with this is that the parallel port driver reads in the port state as an integer, then cuts it up into bits, then the weighted-sum would put them back together as an integer again. A custom component _could_ read the data direct from the port register if you wanted to, and didn't intend to use the extra parport outputs.