A digital process indicator and a process controller are both used in industrial automation, but their functions are different. A digital process indicator is mainly a monitoring device. It receives input signals from sensors or transmitters (such as temperature, pressure, flow, or level sensors) and displays the measured value clearly on a digital screen. Its primary role is to show real-time process data so operators can observe and track system performance. It does not automatically adjust or control the process. It may include features like alarm outputs, a high-brightness LED display, universal input support (4–20 mA, 0–10 V), and optional communication ports, but its core function remains indication only. In contrast, a process controller not only displays the measured value but also controls the process. It compares the actual process value with a predefined setpoint and automatically takes corrective action if there is any deviation. For example, if temperature exceeds the set limit, the process controller can switch off a heater or activate a cooling system. Many controllers use PID (Proportional-Integral-Derivative) logic to maintain precise control. This makes a process controller suitable for applications where automatic regulation is required.