Can't get lathe to Feed

The original issue earlier in this post was the lack of inputs, so this was Andy's solution to use one sensor.
I've got it to feed now by making a few changes, but it will only feed in M3 not M4, I assume because M4 is a negative rotation value.
Also, the actual feed rate looks to be at maximum (near G0 speed) not at the 0.1mm per rev I would expect to see.

I'm beginning to wonder if I would be making life easier for myself if I did add an extra sensor.
I notice on the encoder wheel we have the 100 slots and an additional outer slot.
Am I correct in saying the 100 slots are for reading velocity, and the single outer slot is a strobe for screw cutting?
Is this strobe slot what the 'Z' index pulse looks for ?

Would this be a far more simpler in proven exercise?

The 100 slots are for reading velocity _and_ spindle position feedback
during threading. That is, the Z motion is "geared" to the spindle rotation
by LinuxCNC during threading. The index pulse is used to start synchronized
motion at the same angular position each pass.

If 'spindle-at-speed' does not go true for M4 you might want to use the absolute values tor the 'near' component input.

net spindle-cmd-rpm-abs <= spindle.0.speed-out-abs
net spindle-cmd-rps-abs <= spindle.0.speed-out-rps-abs

Not sure which one you are using now (rpm or rps).

Note that with the LinuxCNC "master" (development) version you can use a single IO line and use missing-tooth index:

linuxcnc.org/docs/devel/html/man/man9/encoder.9.html

This is a new feature, added since this thread started.

rider-83 wrote:

Also, the actual feed rate looks to be at maximum (near G0 speed) not at the 0.1mm per rev I would expect to see

Did you set the F-number to 0.1 and mode to G95? 

Is spindle.0.speed-in scaled in revs per second? If it is rpm then you might see that problem.