How to configure the 7i77 board to do Home Axi Z?

Hello everyone! I'm using the analog signal to determine a limit switch. Through a reading from a magnetic sensor that has an analog voltage output that is read by the 7i77 board, I developed a logic in the LinuxCNC classicladder. The logic is that when the voltage is greater than 7.5 volts then it activates the output %Q81 called MA-Z, when the voltage is less than 1.0 volts then it activates the output %Q80 called MI-Z and the home position is when the voltage is 6 volts it activates %Q82 called HO-Z.



I made a virtual connection in the HAL file

Includes the configuration to activate Home by switvch in the INI file

The machine makes the movements when pressing the + and - buttons of the home z, but when trying to do home axi with exio Z, a movement calculation error appears. As per the video below


 

Please, does anyone have any suggestions, I'm trying to find a way to make this Z axis movement stay in an initial position above the top, to avoid the movement collision of the tools. But I can't get the system and 7i77 board to interpret the virtual limit switch, could it be that I'm missing some configuration in the HAl or INI file so that the home axi Z works correctly?

 
 

I would not use classic ladder for this function as it is not real time, but rather use
the "comp" component to compare the analog voltage to your constants.
The "comp" component also has a hysteresis function like a normal switch
so you will not get a noisy signal near the trip point.

Good morning Mr. PCW
Thank you very much for your feedback and your suggestion.
You are right, I understand.
There is a lot of good documentation on this forum about the "comp" component.
I will try to do it in another, faster way, because I loved the documentation about the "comp" component, but it will take me a few months to understand and write code for this purpose.
So I will just create a logic using halui to raise the Z axis when starting the machine, unfortunately that is the limit of what I know how to do at the moment and it would be the fastest way.
Thank you for all your collaboration.