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Hardware/Software Implementation of Vendor-Directed Stress Method

IP.com Disclosure Number: IPCOM000106134D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 8 page(s) / 233K

Publishing Venue

IBM

Related People

Cowell, DL: AUTHOR [+4]

Abstract

Disclosed is a technique for investigating the operating characteristics of a product design. Vectors are defined within the potential operating range of the product and the exact place along each vector where the product fails to function is determined.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 44% of the total text.

Hardware/Software Implementation of Vendor-Directed Stress Method

      Disclosed is a technique for investigating the operating
characteristics of a product design.  Vectors are defined within the
potential operating range of the product and the exact place along
each vector where the product fails to function is determined.

      Testing involves incremental variance of stress parameters
until the unit under test fails.  Because the test results from many
units under test are analyzed statistically, it is important that
even though the failure point for each unit under test is different,
all results must be in a form that can be analyzed, and compared to
previous test results.  Because of this requirement, several obvious
approaches, such as an exhaustive search of stress combinations and
random combinations of stress settings were clearly inappropriate.
Other options involving "Hardcoding" particular stress settings in
the test control software unacceptably limited flexibility, and
providing a complete list of stress settings before each test was
rejected as inefficient.  What was required was a way for the user to
define the test to be run in a general way, with the test system
filling in the details.

      Conceptually, the method involves the definition of a
multidimensional polar coordinate system.  The first step is the
assigning of stress parameters to dimensions (up to three in the
current software, expandable to any number limited by array
dimensioning).  The origin is defined as the intersection of the
nominal values for the parameters.  Fig. 1 illustrates this concept
for a 3-parameter (3-dimensional) system.  With the coordinate system
defined in this way, the next step is the definition of vector(s)
within this system.  Each vector is defined in terms of two parameter
types:

o   A starting point in the form (x,y,z).

o   A set of angles in the form (theta, ranging from 0 to 360).  A
    number N-1 of angles must be defined, when N is the number of
    dimensions in the operating space.

These parameters completely define a vector.

Algorithmic Perspective - The user-defined starting point (x,y,z)
represents the combination of stress settings at which the first test
will be performed.  The set point translation algorithm translates
these settings into appropriate HEEE-488 General Purpose Interface
Bus (GPIB) commands which are sent to the corresponding equipment by
the GPIB interface utility.  All command translation tables and GPIB
control sequences are included within the software and therefore are
shielded from the user.

      Following the first test, the vector calculation algorithm
calculates stress settings which lie a certain distance along the
vector.  These settings are calculated using the angle information
defined by the user, information on desired maximum step sizes in
each axis defined by the user, and straightforward trigonometric
functions.  The code extract below is the ...