Overvoltage protection. Measurement, control, and regulation without signaling function or function indication. Combined protection of a current loop 0(4) ... 20 mA and the 24 Vdc supply voltage. Protection of the 24 V supply voltage with type III arrester (IEC 61643-11). Pluggable arrester with uninterruptible and impedance neutral plugging or unplugging. Applicable according to the erection standard IEC 62305 / 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.