The parameters
Here is what we evaluate for each safety circuit
- CCF (Common Cause Failure)
This parameter defines the robustness of the circuit against a common cause of system failure. The calculation of the frequency of common failures is performed considering the technology used, the chosen architecture (category), the type of application and the environment in which the machine operates - MTTFd (Mean Time to Failure Dangerous)
This parameter indicates the average life of a component before a dangerous failure occurs. From this parameter it is possible to calculate the dangerous failure rate (ld) - B10d
This value represents the average number of cycles a component can perform before suffering a dangerous failure. To correctly calculate this parameter it is necessary to define the cyclogram of the machine to define the number of operations that the component itself must perform, the hours of operation and the frequency of use - DC (diagnostic coverage)
This parameter defines the diagnostic coverage that the control system is able to perform on the components that perform the safety function.
At the end of the design, Hydroservice releases the report for calculating the performance level [PL] reached which must be integrated by the customer in the technical file of their machine to document the fulfillment of the essential safety requirements defined within the Machinery Directive.