I/O (Inputs and Outputs)

I/O (inputs and outputs) are the electrical signals through which a robot controller communicates with the outside world: reading sensors and machine states (inputs) and commanding grippers, valves, and machines (outputs). Signals may be digital, analog, or carried over a fieldbus.

Every cell needs enough I/O of the right type — to actuate the gripper, confirm part presence, and handshake with machines. Running out of I/O, or having the wrong fieldbus, is a common late-stage integration surprise.

When sourcing a used robot, check the controller's available I/O and supported fieldbuses against your cell's needs. Expansion modules exist but add cost and lead time.