HURCO KMB-1 Control Update

The 5v limits switches, (connected to the 7i77 spare encoder terminals QA3,QB3,IDX3 etc), are registering in linuxcnc randomly. Even though the machine is parked mid stroke, the Y axis min is always true, and I can trigger the X max with a wrench from false to true, but it stays that way with the wrench removed.
Looking at the original control there is a 470ohm resistor to 5v holding the signal to the MUX chip high, and when the limit is triggered, this gets grounded.
Do I need to do something else electrically to gets this working?
Thanks

Are the encoder inputs for the limit switches jumpered for single ended use?

Aha, no they weren't.
But they are now.
Can now toggle them all to change state, but oddly y-min is inverted, and cannot quite see what I have done wrong there.

Thanks again.

Actually the A/B inputs are inverted (which is what you want for an active low home switch input)
But the index input is not inverted.

options:

1. If you have more spare encoder inputs, just use A,B

2. Add 1 or  more  "not" components to invert the polarity of the input-index pin


 

Yes, it is the index pins that are inverted. Thanks.
net min-y <= hm2_7i92.0.encoder.03.input-index is a pin that needs inverting.
i tried with
net min-y <= hm2_7i92.0.encoder.03.input-index-not , but it errors
the other syntax my friendly AI chatbot suggests for this is:-

loadrt not count =2 (I'll just show one here)
add not.0 servo-thread
net my-input-signal-1 <= hm2_7i92.0.encoder.03.input-index
net inverted-signal-1 = not.0.in
net inverted-signal-1 => your-desired-component (which I guess is min-y)

I don't get what the connection is between inverted-signal-1 and my-input-signal-1
Or should all three lines read inverted-signal-1

Still trying to learn.

I still don't follow it I am disappointed in my self to say.

But, have blindly entered:- (Pasted out of the hal file)

loadrt not count=2
addf not.0 servo-thread
addf not.1 servo-thread
net my-input-signal-1 <= hm2_7i92.0.encoder.03.input-index
net non-inverted-signal-1=not.0.in XXXXX
net inverted-signal-1 => not.0.out
net inverted-signal-1 => min-y
net my-input-signal-2 <= hm2_7i92.0.encoder.04.input-index
net non-inverted-signal-2=not.1.in
net inverted-signal-2 => not.1.out
net inverted-signal-2 => max-z

This errors at the line XXXXX with net command needs a pin

Oh dear, I am for sure making heavy weather of this.
The revised code makes more sense in that I can kind of see the linkage now, but linuxcnc is unhappy with the net inverted-signal statement.

Pin 'min-y' does not exist

I was thinking that the point of that line was to create pin min-y

loadrt not count=2
addf not.0 servo-thread
addf not.1 servo-thread

net inverted-min-y <= not.0.in hm2_7i92.0.encoder.03.input-index
net min-y => not.0.out

net inverted-max-z <= not.1.in hm2_7i92.0.encoder.04.input-index
net max-z => not.1.out

"net" syntax is

net signal pin [pin] [pin]

if "signal" does not exist, it will be created
if "signal" does exist, the pins in the net statement will be added
to the existing pins already connected to the signal.

In this case its assumed that the signals min-y and max-z already exist and
connect to linuxcnc's joint limit and possibly home pins.