Time and Usage Units

The Time and Usage Units window defines the time units that will be available for use in any project within the database. This allows users to work with time-based inputs and results in the units that are appropriate for the situation. For example, you can enter data into a Weibull++ life data folio data sheet in hours and then obtain results from the QCP in terms of years. Similarly, in RCM++, RBI or BlockSim, you can define the duration of a maintenance task in terms of hours and specify the total operating time of a system in terms of months.

IMPORTANT: It is important to realize that making changes to the existing units can have implications for all analyses throughout the database; therefore, it is best to set up units once, upon creation of the database.

To define time units, choose File > Manage Repository > Time and Usage Units. (In a secure database, this is available only to users with the "Manage other repository settings" permission.)

The units are defined in relation to a common, or "base," unit so that the software can convert data from one unit to another. For example, the units defined by default assign a conversion factor of 1 to the Hour unit, which indicates that an hour is equal to 1 System Base Unit (SBU); the Year unit has a conversion factor of 8760, which indicates that a year is equal to 8,760 SBUs (i.e., 8.760 hours). Note, however, that the SBU does not have to be hours. You could consider days to be your base unit and define all other units in relation to a day (e.g., an hour would be 1/24th of a base unit, with a conversion factor of 0.04167). The SBU does not have to be the default unit either; you can set any unit as the default by selecting it in the Default column; the default unit will be used automatically each time the software requires a unit.

Each unit must have a name, an abbreviation of up to three characters and a conversion factor. In addition, each unit must be assigned to any one of the two available categories: Time or Usage. (If you will be using the usage format of the Weibull++ warranty folio, only the units assigned to the Usage category will be available for those analyses; units assigned in the Time category are not available in the warranty usage format.)

Use the Delete and Insert buttons below the window to manage the list of units. You can also move a unit up or down its current position by selecting it and using the Move Up or Move Down buttons.

Note: In Weibull++, you can specify which of the configurable repository time units are equivalent to the built-in (not configurable) "warranty time units" used in some warranty folio formats. For details, see Manage Warranty Units in the Weibull++/ALTA documentation.

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