How many I/O and what are they for.???

[JAZZCNC]

Ok so Other INPUTS.

These can be anything from the door bell ringing to kettles boiled.!! . . However common ones are Probes, Drive faults, Spindle faults, low coolant levels, etc.

Then going to slightly higher level machines you have ATC ~(automatic tool changer) these require INPUTS to signal to the controller that things like the pneumatic drawbar is open or closed, the carousel is in or out or at a certain location. Counting the tool positions etc. A typical ATC can require 10+ INPUTS and nearly as many OUTPUTS.

INPUTS also allows you to use external buttons or switches to control features found on the screen so you can make control panels etc. Things like Cycle start, feed hold, Spindle on/off, coolant, etc can all be controlled from buttons feeding signals back into the INPUTS.

Using INPUTS and OUTPUTS you literally can control anything from turning the kettle on to being told when it's boiled and it's for this reason and the fact you don't actually know what you might add or need in the future that you can never actually have too much I/O.

So the best advice is if you think you'll upgrade in the future then buy a controller with the most I/O your budget will run too or at least buy a controller that can add I/O at a later date using cards etc.
Some times you are better paying a little more at the beginning for extra I/O or a better quality card that lets you add it because it will save you money down the road when you need more I/O.