Rockwell Automation Safety Function: Hinge Switch - Manual (Page 11)

Safety Function: Hinge Switch 11
Rockwell Automation Publication SAFETY-AT096A-EN-P – November 2013
SISTEMA software calculates the MTTFd by using B10d data provided for the
contactors along with the estimated frequency of use, entered during the creation of
the SISTEMA project.
The DCavg (99%) for the contactors is selected from the Output Device table of
EN ISO 13849-1 Annex E, Direct Monitoring.
The DCavg (99%) for the hinge switch is selected from the Input Device table of
EN ISO 13849-1 Annex E, Cross Monitoring.
The CCF value is generated by using the scoring process outlined in Annex F of
EN ISO 13849-1. The complete CCF scoring process must be performed when
implementing an application. A minimum score of 65 must be achieved. A CCF of 65
was entered for practical purposes in each case. Calculations are based on one
operation of the safety guard door per hour, therefore, 8760 operations of the
contactors per year.
The measures against CCF are quantified using the scoring process outlined in
Annex F of EN ISO 13849-1. For the purposes of PL calculation, the required score
of 65 is needed to fulfill the CCF requirement. The complete CCF scoring process
must be performed when implementing this example.
Verification and Validation Plan
Verification and validation play important roles in the avoidance of faults throughout
the safety system design and development process. EN ISO 13849-2 sets the
requirements for verification and validation. The standard calls for a documented
plan to confirm all of the safety functional requirements have been met.
Verification is an analysis of the resulting safety control system. The Performance
Level (PL) of the safety control system is calculated to confirm that the system meets
the required Performance Level (PLr) specified. The SISTEMA software is typically
used to perform the calculations and assist with satisfying the requirements of
EN ISO 13849-1.
Validation is a functional test of the safety control system to demonstrate that the
system meets the specified requirements of the safety function. The safety control
system is tested to confirm that all of the safety-related outputs respond
appropriately to their corresponding safety-related inputs. The functional test
includes normal operating conditions in addition to potential fault injection of failure
modes. A checklist is typically used to document the validation of the safety control
system.
Prior to validating the Guardmaster safety relay (GSR) system, confirm that the
Guardmaster safety relay has been wired and configured in accordance with the
installation instructions.