ABB Triguard SC300E Safety Manual

Also see for Triguard SC300E: User manual

Contents

ABB Triguard SC300E Safety Manual Manual pdf 9 page image

Issue 5 - September 2006 Page 9 of 652.3.2 SC300E Functional OverviewA Triguard SC300E system has a fully triplicated architecture from input modules to outputmodules. All Triguard SC300E input and output modules interface to three isolated I/Ocommunications buses, each being controlled by one of the three processor modules.At the input modules, field signals are filtered and then split, via isolating circuitry, into threeidentical, signal processing paths. Each path is controlled by a microcontroller that co-ordinatessignal path processing, testing and signal status reporting to its respective processor, via one ofthe triplicated I/O communications buses.Each of the processors communicates with its neighbours via read only, serial communicationslinks. The processors synchronise at least once per application logic execution cycle, and eachreads the input, output and diagnostic status of its neighbours. Each processor correlates andcorrects its memory image of the current state of the system using a 2-oo-3 software vote,logging any discrepancies found in a local diagnostic history table.Each processor then executes its programmed application logic and sets its respective outputs,via the I/O communications bus, to the required state.Commanded output states are received by an output module's microcontrollers which, using2-oo-3 hardware voters, set the outputs to the field. Any discrepancy between a commandedoutput state and the field output is detected by the microcontrollers and reported to theappropriate processor.All input and output modules can be configured to use a hot spare partner module. In the eventof a fault on the main I/O module its duty can be taken over by the hot spare partner, allowingrepairs to be effected.In maximum configuration a single SC300E system can support a main chassis and 14extension or remote chassis. Each chassis can be populated with 10 modules each containingup to 32 I/O channels, however, for safety configurations all outputs are configured for dual slothot repair. Input modules may be configured for single slot hot repair only where the inputconfiguration or process safety time allows.