1948021A1 | ABB SERIAL I/O INTERFACE MODULE

I/O system S900 is a I/O system for use in hazardous areas. It provides bus-compatible local inputs and outputs (protection classIP20) for connection of digital and analog field instruments. Due toits degree of explosion protection it can be mounted in bothhazardous areas (zone 1 and zone 2) and safe areas.The system consists of a mounting termination unit accommodating the power supply units, the communication interfaces, and theI/O modules. The passive mounting termination unit ensurespower distribution and data transfer, and also provides the connection platform. The power supply units reliably power the entiresystem. One power supply unit is sufficient for normal operation.A second (redundant) power supply unit can be added, to improvethe system availability. The communication interface controls alldata traffic between the I/O modules and the distributed controlsystem (DCS) or the programmable logical controller (PLC). Thecommunication interfaces can also be used in redundancy mode(line redundancy and module redundancy)