The Siemens TD400C is a user-friendly, four-line text display specifically designed for operator control and monitoring with SIMATIC S7-200 programmable logic controllers. It provides a cost-effective solution for displaying messages, process parameters, and alarms directly on the machine. Featuring a backlit LCD screen for clear readability and customizable function keys, the TD400C allows operators to interact with the machine process, enter values, and acknowledge messages efficiently. Its compact and rugged design ensures reliable performance in various industrial environments, making it an ideal HMI for simple to medium complexity applications.