I feel like when I calling Microsoft customer's support...
"We dont know what is your problem, but it works with us..."
I know how Linuxcnc does the threading, and know why it is acceptable with LPT and not acceptable with devices using ethernet link.
LPT uses base_thread, ethernet uses servo_thread, so LPT can be ten times faster.
I told you few posts ago, the servo_thread=1000000 (1 ms period) can make delay that can produce 18 degrees positon error at spindle rotates 3000 rpm.
3000 rpm => 50 rps => 20 ms per revolution.
It is mathematics, everyone can make this calculations.
The solution is not send the extended index in hope the Linuxcnc see it, and resets position to zero when received it.
The solution is send raw_count latched at every real encoder's index edge.
We can restore encoder's index (if we need) from (old != new) at the component.
And we can reset position not to zero, but to real position captured at index edge.
We can be confused, because we use "index" word for different meanings (encoder's output, program variable, hal pin) but we can not change this.
Detailed explanation:
Let's assume the encoder's index edge occurs at 1000 raw_counts.
Time goes, counter counts A/B signals.
The component requests data.
At this moment raw_counts is 1050.
We send both values, counted and latched.
The component knows, the index was 50 counts ago and sets position to 50/scale not to zero. (of course only when hal index_enable pin is set)
What don't you understand?
I didn't want attached my project as offtopic, but I see I must.
