ABB Triguard SC300E Safety Manual

Also see for Triguard SC300E: User manual

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ABB Triguard SC300E Safety Manual Manual pdf 16 page image

Issue 5 - September 2006 Page 16 of 653.3.2.6 Hot Repair AdaptersWherever dual slot hot repair facilities are required, the hot repair adapter boards must be fittedon the chassis backplane.3.4 Classification (SIL level) System Time ConstraintThe Triguard SC300E Safety PLC is a fault tolerant system that inherently tolerates and reportsa first major fault (for example a processor failure).The system diagnostics of a digital output module are not fully available after a first fault is foundon the module. The time allowed to repair this module before a shutdown to the safe state isrequired is the system time constraint.The Triguard SC300E System may be configured with or without time constraint dependent onthe safety output configurations used.In systems configured with single outputs and final elements, then a time constraint will apply.The time constraint has been conservatively calculated by TUV dependent on the SIL level (lowdemand) and based on worst case of all outputs used.Time constraint for SIL 3 systems is 2353 hoursTime constraint for SIL 2 systems is 7440 hoursTime constraint for SIL 1 systems is 23528 hoursTime constraint may be extended if less than 32 outputs are safety related, for extended timeconstraint values refer to the table Appendix 2.3.4.1 Without System Time Constraint Dual Final ElementsIn AK6 (SIL 3) classified safety loops it is probable that the safety loop final element has at leasttwo possible operational paths (Figure 3 shows a typical configuration).Providing each final element is driven from a separate SC300E digital output on separate digitaloutput modules, the system will have no time constraint.DualSolenoidValveDual Solenoid ExampleMDO Card 1 TCMDO Card 2 TCSC300E TMRSystemMDO Card 1 TC ESD Valve 1MDO Card 2 TC ESD Valve 2SC300E TMRSystemDual Valve Example