PRISM Forum - Message Replies

Topic: PRISM Questions and Answers
Topic Posted by: SRC ( )
Organization: SRC
Date Posted: Wed Jan 12 8:33:33 US/Eastern 2000
Topic Description: Welcome to the PRISM forum! Please feel free to post your questions and comments about the PRISM assessment software here.

Back to message list Show all replies About this forum

Original Message:

Posted by: Boutbien Laurent ( )
Organization:MBDAM (Châtillon France)
Date posted: Wed Feb 27 10:21:13 US/Eastern 2002
Subject: similarity between software and paper guide
Using your own example for a system analysis, i was focusing on the study concerning the reliability calculation for the four resistance R1-R4 of A3A2 sub-assembly. The aim of this study was to identify the relation between the software and the tabulated figures within the paper guide. Keeping the original parameters (i.e element temperature calculation is based on ambient temperature and default temperature rise), I was not able to check the default tabulated parameter for the following factors : PiTO , PiTE , Pi DT and lambdaSJ. I am aware that choosing different options for the element temperature calculation will induce different Pi-factors. However I do not understand why selecting the default option is not leading to the selection of the default parameters (these summarised in the tables : table C5 page 192 version 1.2). Can you please explain why the parameters are not corresponding to the ones expected (for ground stationary, indoors). Thank you for your help. Best Regards


Subject: Resistor Pi Factors for PRISM
Reply Posted by: David Dylis ( )
Organization: Reliability Analysis Center (RAC)
Date Posted: Thu Feb 28 15:29:00 US/Eastern 2002
I performed the calculation using the default values for a Ground, Stationary, Indoors environment and it appears that the PRISM User manual and PRISM software values match. Please verify that the default conditions are being used in your calculations. The default conditions for a Ground, Stationary, Indoors environment environment are as follows:

Operating Temperature (30C)
Dormant Temperature (23C)
Relative Humidity (40%)
Vibration (0.0 grms)

You can also reset the environment back to its default conditions by clicking on the box with the circular arrow that appears next to the environment pull-down box within the PRISM software.

If you have any additional questions, feel free to contact me: David Dylis
Data and Information Manager
Reliability Analysis Center (RAC)
201 Mill St.
Rome, NY 13440-6916
Phone: (315) 339-7055
Fax: (315) 337-9932
RAC Web Site:

Reply to this message