The GALILEO SMS (SIL Multisystem) is an advanced multifunction gas detection control panel designed to comply with the SIL (Safety Integrity Level) requirements, according to the European Standard EN 50402 on Functional Safety. The functional safety is aimed at supervising and managing the behaviour of an overall system in case of failures. To assure a full redundancy, the control unit‘s main board is designed around 2 powerful microprocessors that communicate each other the monitored data, ensuring the complete availability of all main board functions even in the case of a failure in one microprocessor. A broad range of self-testing facilities are implemented to detect and localize possible faults. The redundancy offered by every module being part of the system, added to the possibility to communicate with remote input/output modules via a redundant closed BUS, makes this system comply with the Functional Safety requirements up to SIL3. The GALILEO SMS consists of a control unit, used for monitoring and controlling, connected to an optional number of Analogue Input Modules (AIM), LOOP modules and RELAY modules. The system will be connected in two digital RS485 (EIA¬485) type closed loops capable of accommodating: