The following diagram illustrates the control function:
The control function is where things are controlled, moved, activated, and initiated. The control system is what makes actuators engage, valves open, and motors run. The control actions can either be initiated by an operator pushing a button or changing a set point on an HMI screen, or it can be an automated response as part of the process control.
From a security perspective, if an attacker can manipulate the values (the input) the control system reacts to or if the attacker can change or manipulate the control function itself (the control program), the system can ...
