Users with the "Manage other repository settings" permission can define 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 time units that are appropriate for the situation. For example, you might have a data set where times to failure were recorded in hours, but you want to predict the item's reliability after a year of operation. Having a set of units defined for the database allows you to enter the data into the Weibull++ standard folio data sheet in hours and then obtain results from the QCP in terms of years. Similarly, you could accommodate a situation in RCM++, RBI or BlockSim where you need to define the duration of a maintenance task in terms of hours and to specify the total operating time of the system in terms of months.
IMPORTANT: In previous versions, time units were not specified, but were assumed to be consistent throughout the analysis. In Version 9, units are now defined for the entire database and can be modified. 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 > Manage Units to open the Define Units window.
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).
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.
Note: If you will be using the usage format of the Weibull++ warranty folio, note that 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.
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.
To edit an existing unit, click inside the cell and edit the text.
To add a new unit to the bottom of the list, click inside the last row and type the text.
To delete a unit, select the row and click the Delete icon. There is no undo for delete.
To insert a new unit above an existing one, select the existing unit and click Insert.
To move an existing unit up or down in the list, select the row and click the Move Up or Move Down icon.
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