Frequently Asked Question

I have a SIF where the Final Element Part include two solenoids in 1oo2 logic. How can this be modelled in exSilentia?
Last Updated 4 years ago

The easiest solution is to select the generic 1oo2 solenoid from the equipment database in the tool. This is representative of a generic three way solenoid.

Otherwise, if you want to model a specific solenoid in a redundant configuration you will need follow the following approach:

1. Create an intermediate SIF (temporary SIF)
2. In this SIF define 1 final element group with 1oo2 or 2oo2 voting as applicable and select the appropriate solenoid
3. Set the proof test interval to the same value as in the final SIF
4. Set the mission time of this SIF equal to the proof test interval of the final element group that the solenoids are part of.
5. Set the demand mode to high demand

The tool will calculate a PFH and a MTTFS that you can use to determine the equivalent failure rates of the redundant solenoid configuration.

In your final SIF, create a user defined final element interface. When entering information on the user defined device, the failure rate section has a 'Based on' selection that allows you to calculate based on PFH and MTTFS. From the 'Based on' drop down, choose PFH, then enter the values in the fields that appear. The tool will calculate the equivalent lambdaDU and LambdaSU.

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