shared home/limit swiches

i have a RPI-4 running linuxcnc 2.9.10. using  a 7i96s, the qtdragon GUI, and inductive proximity switches. i have one switch acting as both home and limit.
everything is working perfectly except for a minor annoyance on the status bar. when i home, and the axis move toward the home switch, initially trips the switch, it properly reverses off the switch (search velocity is positive, and latch velocity is negative so the axis is of the switch), then continues on to the final home position. but when it initially hits the switch, the status bar shows "hard limit tripped". the machine doesn't stop, so it is properly ignoring limits while homing. the fault clears itself after several seconds. just curious why this is happening. i thought i read somewhere that it re-enabled limits after the cycle was done, apparently not the case? I assume if it bothers me enough i could learn/write some HAL code to block it in the GUI?? or better yet just use the switch as home, and just rely on the soft limits

If you have shared home/limit switch, you should add a HOME_OFFSET to move off the switch before homing finishes to avoid this.

that was what I understood to be the case...but it isnt!!! ive done .1" to 1" offsets in both positive and negative. it dont matter. all that does is change the final parking position of home.
The hard stop tripped status shows up instantly when the axis hits the switch initially.
this is just a visual annoyance at this time so ill deal with it the way it is.

Shared home/limit switches are pretty common so I would expect more
complaints about this if this always happened.

I wonder if this is possibly  caused by contact bounce.

Have you set the switch input inm pins to "slow" ?

I was thinking the same thing about if it was "normal" I would have been able to find those posts. So i just assumed maybe I just didnt set something up right yet (like the slow parameter you mentioned, Ill give that a try). thanx

oh, by the way, im using inductive switches.

i tried
setp hm2_7i96s.0.inm.00.input-00-slow true
but saw no diffference. maybe there are other things that need to go along with that but im no HAL programmer.
as such i made friends with google AI and had him write me some code to block the hard limit status in the status bar. it took several passes, and even i got to call him out when i knew something was wrong. eventually here is what he came up with, so i put it in my custom.hal and it works. figured i would post it in case anyone else runs into this and finds this thread;

# =====================================================================
# OVERRIDE X, Y, Z LIMIT FLASHING DURING HOMING (Safe from pncconf)
# =====================================================================

# 1. Load 3 instances of each logic gate (one per axis/joint)
loadrt and2 count=3
loadrt not count=3

# 2. Add them all to the real-time processing thread
addf and2.0 servo-thread
addf and2.1 servo-thread
addf and2.2 servo-thread
addf not.0 servo-thread
addf not.1 servo-thread
addf not.2 servo-thread

# =====================================================================
# JOINT 0: X-AXIS CONFIGURATION
# =====================================================================
# Disconnect pncconf's direct mapping to the X limit pins
unlinkp joint.0.neg-lim-sw-in
unlinkp joint.0.pos-lim-sw-in

# Invert X homing status (Output goes FALSE when homing)
net x-is-homing <= joint.0.homing
net x-is-homing => not.0.in

# Mask the X signal during homing
net min-home-x => and2.0.in0
net x-mask-control <= not.0.out
net x-mask-control => and2.0.in1

# Route masked signal back to X limits
net min-home-x-gated <= and2.0.out
net min-home-x-gated => joint.0.neg-lim-sw-in
net min-home-x-gated => joint.0.pos-lim-sw-in


# =====================================================================
# JOINT 1: Y-AXIS CONFIGURATION
# =====================================================================
# Disconnect pncconf's direct mapping to the Y limit pins
unlinkp joint.1.neg-lim-sw-in
unlinkp joint.1.pos-lim-sw-in

# Invert Y homing status (Output goes FALSE when homing)
net y-is-homing <= joint.1.homing
net y-is-homing => not.1.in

# Mask the Y signal during homing
net min-home-y => and2.1.in0
net y-mask-control <= not.1.out
net y-mask-control => and2.1.in1

# Route masked signal back to Y limits
net min-home-y-gated <= and2.1.out
net min-home-y-gated => joint.1.neg-lim-sw-in
net min-home-y-gated => joint.1.pos-lim-sw-in


# =====================================================================
# JOINT 2: Z-AXIS CONFIGURATION
# =====================================================================
# Disconnect pncconf's direct mapping to the Z limit pins
unlinkp joint.2.neg-lim-sw-in
unlinkp joint.2.pos-lim-sw-in

# Invert Z homing status (Output goes FALSE when homing)
net z-is-homing <= joint.2.homing
net z-is-homing => not.2.in

# Mask the Z signal during homing (Change 'min-home-z' if pncconf used 'max-home-z')
net min-home-z => and2.2.in0
net z-mask-control <= not.2.out
net z-mask-control => and2.2.in1

# Route masked signal back to Z limits
net min-home-z-gated <= and2.2.out
net min-home-z-gated => joint.2.neg-lim-sw-in
net min-home-z-gated => joint.2.pos-lim-sw-in

rubes wrote:

# =====================================================================
# JOINT 0: X-AXIS CONFIGURATION
# =====================================================================
# Disconnect pncconf's direct mapping to the X limit pins
unlinkp joint.0.neg-lim-sw-in
unlinkp joint.0.pos-lim-sw-in

# Invert X homing status (Output goes FALSE when homing)
net x-is-homing <= joint.0.homing
net x-is-homing => not.0.in

# Mask the X signal during homing
net min-home-x => and2.0.in0
net x-mask-control <= not.0.out
net x-mask-control => and2.0.in1

# Route masked signal back to X limits
net min-home-x-gated <= and2.0.out
net min-home-x-gated => joint.0.neg-lim-sw-in
net min-home-x-gated => joint.0.pos-lim-sw-in
 

I don't understand why and what for ...

In hal file :
net min-home-x <= parport.0.pin-12-in-not => joint.0.home-sw-in => joint.0.neg-lim-sw-in

In ini file :
[JOINT_0]
HOME_IGNORE_LIMITS = YES

that is what everyone gas been telling me (the part about home_ignore_limits). that other line i dont understand because i am not a HAL programmer. but there is probly several ways to accomplish this. if your one line per axis accomplishes the same thing, it is certainly more elegant and efficient.

the problem, which is really just an annoyance, is that even though ignor_limits is set to yes, when the axis is homing and touches the switch, it flashes the hard limits tripped error on the status bar for several seconds (At least on my machine it does, apparently im the only one). it doesnt actually stop the machine though, so the logic is properly ignoring the limit switch. I just wanted to cleanup the screen a bit, try and learn some HAL, and yeah even try out this AI thing since ive never been a big fan. its actually kind of cool.

oh, one more thing, i'm using QtDragon

rubes wrote:

that is what everyone gas been telling me (the part about home_ignore_limits). that other line i dont understand because i am not a HAL programmer. but there is probly several ways to accomplish this. if your one line per axis accomplishes the same thing, it is certainly more elegant and efficient.
 

Personally, I like writing statements on separate lines. I find its easier to understand and maintain