Calculation Data for MIL-HDBK-217, Telcordia, Bellcore, or Mechanical Model
The following form is shown in the Calculation Data pane when a MIL-HDBK-217, Telcordia, or Bellcore model is either inherited or selected for Calculation model. This same form is also shown when the Mechanical model is selected.
The following table describes the data fields in the Calculation Data pane for these models. Field availability depends on selections made in various fields.
Field | Description |
|---|---|
Name | The name assigned to the assembly in the System Tree Items table. |
Calculation model | The reliability prediction standard or model to use to compute the predicted failure rate of the assembly. Choices include all licensed models. As described in Model Selection, a lower-level assembly inherits the model selected for its parent assembly, but when a MIL-HDBK-217, Telcordia, or Bellcore model is selected, you can specify an override model, which its child items also inherit. |
Method | The Telcordia calculation method to use to take burn-in, laboratory, and/or field data into account. This field is available when Telcordia models are licensed. When a method is selected, the Method Data pane for that method is shown so that you can enter the collected burn-in, laboratory, and/or field data. For more information, see Telcordia Calculation Methods. |
Temperature | The operating temperature of the assembly in degrees C. For more information, see Operating Temperature. |
Temperature delta | A temperature adjustment value in degrees C. This value is added to the operating temperature to get the ambient, environment, or case temperature, depending on which is appropriate for the model selected. While this field is unavailable for the top-most assembly (system), it is available for all lower-level assemblies. |
Environment, 217 / Telcordia | The surroundings in which the assembly operates. This field appears when a MIL-HDBK-217, Telcordia, or Bellcore model is selected. For choices, see MIL-HDBK-217, Telcordia, and Bellcore Environments. Environment selections are inherited and overridden in the same manner as calculation model selections. For more information, see Model Selection. |
Environment, dormant | The surroundings in which the assembly is dormant. The choices for MIL-HDBK-217, Telcordia, and Bellcore models are Ground, Airborne, Naval, and Space. |
Duty cycle | The percentage of time that the assembly is in an active state. For more information, see Duty Cycle. |
 | The subsequent fields specify whether assembly results are calculated or specified. For more information, see Calculation Data for Specifying Whether Assembly Results are Calculated or Specified. |
| | When Telcordia Issue 3 or Telcordia Issue 2 is selected for Calculation model and either Specified, Failure Rate or Specified, MTBF is selected for Failure rate type, then Standard deviation specified is the last field shown. In it, you specify a standard deviation for the assembly’s specified failure rate or MTBF value. |