For example, traditional step motor systems run in open loop control. That means the drive electronics continuously supply current to the motor whether or not the load is demanding torque.

Fig. 5 is a simple block diagram of the desired system. An example of a closed-loop system is the use of a thermistor for temperature feedback, with results shown in Fig. 6 .

Industrial control systems can be categorized in two types: open-loop and closed-loop systems. The open-loop control system is a continuous control system that provides no feedback from its output.