The Yokogawa ASI143-S00 is a single-channel, non-isolating (zener) safety barrier designed for DC switch input (discrete input) signals in intrinsically safe (IS) applications. Its primary function is to protect hazardous areas by limiting the voltage and current that can reach a field device, such as a mechanical switch, proximity sensor, or electromechanical relay. It provides a passive signal path for the dry contact signal to the control system in the safe area (e.g., a PLC/DCS digital input card). The "-S00" suffix denotes a standard configuration within this series.
