homing with Phase Z encoder on MESA 7i96s

To check, in halcmd:

sets b-index-enable true

and watch b-index-enable in halshow

Then move the axis past an index mark

b-index-enable should go false when the index is detected

yes, I checked all that with 4 encoders but I never saw any change in the Z signal. I think my .hal is compliant. Could there be a connection subtlety on the 7i96s card?

You are not guaranteed to see any change in the Z signal
as its a short pulse and quite hard to catch at the 1 KHz servo thread.
(especially with higher resolution scales)

This is why the actual index event is captured in hardware.

The index (Z) signal is only provided as a hal signal for debugging
or using it as a GP input. It's normally not of any other use.

If index enable goes false on an index event, the index was detected.
 

I don't quite understand, but that means I could never use it as a homing device? my encoders are 2500 pulses/ 10000 pulses quadrature hole.

No, homing to index is common and fully supported.

I'm just saying that the actual index hal pin is not useful
for homing. The index-enable pin is what's used to communicate
index information from the hardware/driver to LinuxCNC

That is, this hal statement:

net phaseZ [HMOT](CARD0).encoder.00.input-index

Doesn't do anything useful.

But this hal statement:

net b-index-enable joint.3.index-enable <=> [HMOT](CARD0).encoder.00.index-enable

Allows LinuxCNC to enable index detection AND allows the driver to inform LinuxCNC
when the index has been detected.

To test whether the index hardware is working (assuming you can move the axis past
an index mark), you would:

With LinuxCNC running,  use halshow to watch the signal b-index-enable
and then with either halshow or halcmd, set b-index-enable true"

halcmd sets b-index-enable true

halshow should now show b-index-enable true

now, if you move the axis past an index mark, b-index-enable should go false.

This is how you test for correct index operation.

what do you think of my configuration:

# --- Encodeur configuration ---
setp [HMOT](CARD0).encoder.00.counter-mode 0
setp [HMOT](CARD0).encoder.00.filter 0
setp [HMOT](CARD0).encoder.00.scale [JOINT_3]ENCODER_B_SCALE
#setp [HMOT](CARD0).encoder.00.index-enable true
setp [HMOT](CARD0).encoder.00.index-mask 1
setp [HMOT](CARD0).encoder.00.index-invert 0
setp [HMOT](CARD0).encoder.00.index-mask-invert 0

# --- Feedback position/velocity via encodeur ---
net b-pos-fb <= [HMOT](CARD0).encoder.00.position
net b-pos-fb => pid.b.feedback
net b-pos-fb => joint.3.motor-pos-fb
net b-vel-fb <= [HMOT](CARD0).encoder.00.velocity

# --- Index pour homing ---
net b-index-enable joint.3.index-enable <=> [HMOT](CARD0).encoder.00.index-enable
net phaseZ [HMOT](CARD0).encoder.00.input-index

# --- Raw counts (optionnel debug) ---
net b-pos-rawcounts <= [HMOT](CARD0).encoder.00.rawcounts

# --- Switches (home et fins de course) ---
net b-home-sw => joint.3.home-sw-in
net b-neg-limit => joint.3.neg-lim-sw-in
net b-pos-limit => joint.3.pos-lim-sw-in