Windows 2000 Compatibility, Analyzing Grouped vs. Ungrouped Data in Weibull++ and other Tool Tips from Reliability HotWire


Reliability HotWire	Issue 2, April 2001
Tool Tips
Can I speed up the data entry process in Weibull++ and ALTA? There are some shortcuts available in Weibull++ and ALTA for speeding up the data entry process. In a Data Entry Spreadsheet that is configured for grouped data entry, it is not necessary to enter a value for the “Number in Group” if the value is 1. Weibull++ and ALTA will automatically insert the value of 1 for the cells that are left blank in the “Number in Group" column. Another shortcut can be used when a “State F or S” column is displayed in the Data Entry Spreadsheet. In this case, the cells in the “Time Failed” column can be entered first. When a positive value is entered, Weibull++ and ALTA automatically insert an “F” in the corresponding “State F or S” column position. When a negative value is entered, the applications automatically insert an “S” in the "State F or S" column. For example, for a right censored item at 100 hrs, type "–100" in the “Time Failed” column. An "S" will automatically be inserted into the "State F or S" column. What do I need to know before analyzing data from an Accelerated Life Test with two types of stresses? Before analyzing data with more than one stress type (e.g., temperature and humidity), there must be an "overlap" of the stress levels in order to be able to fit a combination model (life-stress relationship). This is because a relationship between the stress levels and the failure behavior of the product needs to be established. For example, consider a situation where Stress 1 has levels A and B, and Stress 2 has levels X and Y. If the failure data is only collected where the stress levels are at A and X and at B and Y, a mathematical relationship between the two stress types and reliability cannot be obtained. If you attempt to analyze such a data set in ALTA using one of the 2 combination models available in the application (Temperature-Humidity or Temperature-NonThermal), a message box will inform you that such an analysis is not possible. The same failure data will have to be collected at a stress combination of A and Y or B and X in order to obtain a solution for the data set. How do I get the latest software updates? An integral part of ReliaSoft's continuous improvement process involves issuing updates for all of our products to address technology changes, functionality requests and/or issue resolutions. Same version software updates (i.e., same major version number such as 6.X.X) are made available to all licensed users free of charge. We encourage you to update your product when a new update is released. Service releases are available via the ReliaSoft.com Web site. Consult the product home page for the product of interest or consult the Reliability Software Downloads table for updated information. When reinstalling older versions of software on a PC that is running Windows 2000, I get an error message saying that I need a service pack for Windows NT. What can I do to fix this? If you have a CD-ROM of ReliaSoft products shipped before the release of Windows 2000 (i.e., February 2000) you will encounter this issue when reinstalling any of the applications from these CDs on Windows 2000 machines. Free updates for these products are available on the ReliaSoft Web site. For more information (and download information) see http://www.reliasoft.com/support/rs20006.htm.

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