Proximity Sensor Home Switch Issues

I'm using NC PNP proximity sensors for homing. I'm using a Mesa 7i96s card. I am providing 24 volts to each sensor and each sensor displays a red indicator light so I know they are getting power. When I move an object close to the sensor, the light turns off until I move the object away. Then the light turns back on. When I look at the input pins where each sensor is connected, I can see a yellow light just behind the input pins which would indicate to me that the board recognizes the sensor is present. In the configuration wizard I have the correct pins selected and am using the x home, y home and z home options. When I try to home any axis, the sensor light turns off when it should trigger, but my axis continues to move requiring I hit the emergency stop. I'm not sure if I'm selecting the correct settings in hal show, but under a section 7i96s I found a homing option for each axis listed as hm2.7i96s.0.gpio.005.in which has a yellow dot next to it. The next line is hm2.7i96s.0.gpio.005.in_not which has a red dot next to it. I have a line for each of the 3 sensors but is listed as 006 and 007 which is the correct pins I'm using. When I move an object close to the sensor, it changes from the light on to the light off but I don't see any changes in hal show. Any ideas as to what I'm doing wrong, or, what I might do to trouble shoot the problem?  I've spend several hours messing with it today.

Sounds like maybe a wiring error if the GPIO hal pins always read high

Do the GPIO pins show high (Yellow in the halshow "WATCH" pane)
If you run LinuxCNC with the input pins unconnected?

(unplug the switch connector(s) from the 7I96S and run LinuxCNC to test)

When connected, the halshow home pins are yellow.
When I move an object close to the sensor, the halshow remains yellow even though the light on the sensor goes off indicating it senses an object.
When I remove the pins, the halshow changes from yellow to red and I can still move the axis.
After removing the pins I turn the power off to the 7i96s and then power back on. I reopen Linuxcnc. Halshow pins are red and I can move the axis.

I know this is more than you asked for but I thought I would try all the combinations to see what would happen.

Andy,
Thank you so much for your reply. I can't express how thankful I am for people lik you that take the time to help people like me.

You might have something there. I'm assuming when you spoke of the power supply floating relative to the 7i96s, that the 7i96s should be grounded using the same ground that supplies ground to the power supply. I know there is a ground screw on the 7i96s but I have not grounded it yet. I will certainly get a ground to the 7i96s right away and see if that solves my problem. Following is how I have everything wired:

I used Dinkle Combiner terminal blocks to split the power from the 24v power supply.
The blue wire is connected to v- and brown to v+.
The black wire is connected to the input pin on the 7i96s
I will run a ground from the same earth ground the comes in from the power cord that supplies the main power.

Does that sound right to you?

Andy is talking about the 7I96/7I96S input common. This is TB3 pin 12.
This must connect to the 24V supply ground, the same pin as the
Proximity sensor ground.

The frame ground pin on the 7I96/7I96S should be grounded to earth
ground for EMI/ESD reasons, but this is unrelated to your input issue.

Ok... Thanks for clarifying where the ground need to originate and where it needs to be connected to the 7i96s. As I reread his reply, I see that he did specify the ground should connect to the input common pin. Thanks again!