Surge protection. Measurement, control, and regulation without signal function or operational display. The following signals are protected under binary signals (SL - symmetrical load): Switching signals with and without a common reference potential of 24V, 5V to 60V. Two-wire systems typically have a common reference potential for binary sensors, actuators, and indicators such as limit switches, push buttons, position transmitters, photoresistors, contactors, solenoid valves, and signal lights. The plug-in surge protection allows for interruption-free and impedance-neutral plugging or unplugging. Testability through the V-TEST device. Space-saving design for up to four binary signals. Designed with a ground-free PE connection to avoid stray currents in case of potential differences. Complies with installation standards IEC 62305 and IEC 61643-22 (D1, C1, C2, and C3). Integrated PE foot safely diverts up to 20 kA (8/20 μs) and 2.5 kA (10/350 μs) to PE. Colored labeling of voltage levels enables quick identification in the control cabinet. The safety function includes a coding element for different voltage levels.