Hi Nicklamp
Please see below link, it gives the ranges for standard and enhanced controllers.
At the bottom of that there are further links to webinars that will help setting up.
if you have succeeded in reading MI's then you have the hardest part done.
To read MI's you probably used the modbus block 3 - "read holding registers", for inputs use block 2- Read Inputs.
Input 0 will be 6000h
https://support.unitronics.com/index.php?/selfhelp/view-article/vision-and-modbus-communication