Surge protection. Measurement and control without signal function or operational display. The following signals are protected by binary signals (SL - balanced 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 sensors, light barriers, contactors, solenoid valves, and signal lights. The pluggable surge protection allows for interruption-free and impedance-neutral plugging and unplugging. Testability via V-TEST tester. Space-saving design for up to 4 binary signals. Version with ground-free PE connection to avoid stray currents in case of potential differences. Can be used in accordance with the construction regulations IEC 62305 and IEC 61643-22 (D1, C1, C2, and C3). Integrated PE foot safely conducts up to 20 kA (8/20 μs) and 2.5 kA (10/350 μs) to PE. Color-coded voltage levels for quick identification in the control cabinet. Safety function with coding element for different voltage levels.