Reliability HotWire

Reliability HotWire

Issue 136, June 2012

Tool Tips

*What does the "System is new on start date" option mean in the Weibull++ event log?

The event log folio in Weibull++ allows you to enter information about the dates/times when a failure (or another type of event) brought a system down, and the dates/times when it was restored to operation. The software then automatically extracts the data sets you can use to analyze the times-to-failure and times-to-repair.

Event log control panel

If you select the System is new on start date check box on the Main page of the control panel, this indicates that the system had not accumulated any operating time prior to the date when you started recording data in the log. Therefore, the time to the first occurrence of an event will be recorded as complete data (State = F in a standard folio data sheet).

If you clear the check box, this indicates that the system had already been operating for some unspecified period of time before you started recording data in the log. Therefore, the first time will be recorded as censored data (State = S in a standard folio data sheet).

When you calculate an event log folio, the software automatically analyzes the extracted data and provides the results in two reports that can be accessed from the Results area of the control panel. To see the actual data sets that were used to calculate these results (or if you want to perform other analyses on your own), choose one of the commands under Event Log > Transfer Life Data or click one of the transfer icons on the control panel. You have the option to transfer the data to a new Weibull++ standard folio or to replace the data in an existing standard folio. 

*Can I use different time units for different types of inputs/results in Synthesis applications?

With the release of Version 8, all of the Synthesis Elements (Weibull++, ALTA, BlockSim, Xfmea and RCM++) allow you to specify different time units for data, inputs and results.

To manage the time units available within any given Synthesis repository, an authorized user can choose File > Manage Repository > Manage Units. For example, using the default equivalencies shown in the following picture, 1 day = 24 hours, 1 month = 730 hours, and so on.

Manage Units window

While performing analyses in this repository, users will be prompted to specify the time units when applicable, and they can change the units later if necessary. For example, in a Weibull++ standard folio:

  • You can select the units in the setup window that appears when you create a new data sheet.
  • You can change the units for an existing data sheet by clicking the Change Units icon on the control panel. You will have the option to leave the existing numbers unchanged (e.g., 10 days becomes 10 hours), or to automatically convert the data using the specified base unit equivalency (e.g., 10 days becomes 240 hours).

Change Units icon

  • When you calculate results in the QCP, you can use the Units drop-down list to choose the units that will be used for the time inputs and/or results.

Quick Calculation Pad (QCP)

Likewise, when defining the universal reliability definition (URD) resources that can be maintained from any Synthesis application, it may be more convenient for users to make some inputs in terms of months (e.g., the scheduled interval for preventive maintenance), other inputs in terms of days (e.g., the logistic delay while waiting for a repair crew to be available) and still other inputs in terms of hours (e.g., the time required to perform the repair). 

Maintenance Task window