Controlling spindle using python scripts and Modbus TCP

Hi All,
I have been playing with this for days and have not cracked it. I was using AI for answers but every solution failed. I want to do the following. I have the python code sorted but getting LinuxCNC to call the python scripts seems to be the problem. The python script sets the Modbus TCP registers on the VFD.Spindle forward, pass the value 1 to my python script as an argSpindle reverse, pass the value 2 to my python script as an argStop spindle, pass the value 5 to my python script as an argSpindle speed, pass a value between 0 and 200 to a python script.can anyone offer a solution. Cheers
 

Sounds like a user component.

There are some examples, for example the mitsub_vfd.py here github.com/LinuxCNC/linuxcnc/tree/master/src/hal/user_comps