Indicates the number of rows to display in the table shown lower in the window.

Indicates the stress that is temperature-related. This parameter is shown only when Temperature-NonThermal or Generalized Eyring is selected for Life stress model. These two models must have two and only two active stresses. One stress must be thermal, and the other must be non-thermal. For this parameter, you select the stress that is thermal. Choices are all active stresses in the table below. The default is the first active stress. If you make changes in the Active or Name columns in the table, the choices are updated.

Indicates the type of stress applied to accelerate component aging. Choices are Constant and Time Varying (CEM). The default is Constant.

The model to use to extrapolate the data in the ALT data set to predict reliability of the product at normal stress levels. Choices are Arrhenius, Eyring, Inverse Power Law, Temperature-Humidity, Temperature-NonThermal, Generalized Eyring, Proportional Hazards, and General Log-Linear. The default is Arrhenius. Only the Arrhenius, Eyring, and Inverse Power Law models support time-varying stresses. When any other model is selected, the stress is constant. For more information, see Life Stress Models.

Table

Descriptions follow for the columns in the table. Each row is a stress. Your selection for Stress count determines the number of rows.

Indicates whether this stress is active. When this checkbox is selected, the stress is shown as a column in the ALT Data Points pane, and the data that you enter in this column is used in ALT calculations. When this check box is cleared, the stress is inactive, which means that no column is shown for it in the ALT Data Points pane. To indicate that a stress is inactive, the other columns in the row are unavailable. The number of stresses that must be active depend on your selection for Life stress model. When you click OK, a check is performed to verify that the required number of stresses are active. For more information, see Stress Data Validation.

The name for the stress. The names here are synchronized with the stress column names in the ALT Data Points pane. By default, the column names are Stress 1 through Stress 10. However, changing the name here changes the column name in the ALT Data Points pane. Likewise, changing the column name in the ALT Data Points pane changes the name here. For information, see Changing the Names of Data Point Columns.

The normal stress that the system experiences when it runs. This value is a calculation input. It cannot be blank. The default is 0. When you click OK, a check is performed to verify that the value that you entered is equal to or greater than the minimum value required by your selection for Conversion.

Specifies the default value for the stress column in the ALT Data Points pane. The name for this table column depends on your selection for Stress.

The method for converting supplied stress values. The default is None, which means that no conversions are performed. Other choices are for converting between Celsius, Fahrenheit, Kelvin, and Rankine temperature scales and for multiplying and dividing by the value entered for Factor. When you click OK, a check is performed to verify stress values.

For constant stress, the minimum value depends on its conversion type:

For time-varying stress, the stress profile must be valid. The stress level values supplied in this profile are validated in the same manner as the value for a constant stress.

The value to multiply by or add to the stress value when Multiply By or Divide By is selected for Conversion. If some other choice is selected, this column is unavailable. The default is 1. The minimum is 0. If you enter a negative number, a window opens, indicating that the value must be greater than 0. Once you click OK, you can enter a valid value.

The model to use to transform the stress data. This column is shown only when General Log-Linear is selected for Life stress model. Choices are: