User Manual

Reliability Demonstration Report
MaxBotix
®
Inc.
Document Release: 05/12/2010, pg. 4 of 10
10
0
MaxBotix, MaxSonar, XL & WR are trademarks of MaxBotix Inc.
v1.1b • 07/2009 • Copyright 2005-2010
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Web:
www.maxbotix.com
2 High Temperature Operational Life Test (MTBF)
2.1 Test scope
The purpose of this test was to use High Temperature Operational Life Testing to
demonstrate the long-term operation of our Maxbotix Inc., MaxSonar™ sensor line. The
test started on January 18, 2010 and ended on March 15, 2010.
2.2 Test Samples
The test was carried out on 50 units. Of these, a sample of 25 units was issued from our
production stock to represent the XL product line and a sample of 25 was issued to
represent the WR product line. All units were prescreened on the assembly floor to
ensure correct operation before the test using the same method as our regular production
parts.
2.3 Test Conditions
During this burn-in time the units under test were powered at 5.0 Volts, and the product
was commanded to range continuously. All units were installed in a test chamber that
maintained a temperature of 85°C +/- 3°C. All units were monitored once daily for the
following parameters: Mean Voltage, Peak to Peak Output Voltage, Maximum Output
Voltage, Minimum Output Voltage, Analog Output Voltage, Average Current Draw, &
Voltage of Operation (Input Voltage). During this time temperature data was monitored
to ensure the correct operation of our temperature chamber.
All parts were subjected to test conditions for a 1340.5-hour duration. After the test was
completed all units were removed from the test assembly and inspected to verify the
integrity of the components and the overall operation of the units under test.
2.4 Test Results
No failures were observed during the course of this test. In addition, all product passed
production tests after this life testing was completed.
By testing 50 units for 1340.5 hours data was accumulated for 67,025 hours of combined
product usage hours. During the course of this test no failures were observed, with an
calculated mean time between failure (MTBF) of 232,896 hours with a 90% confidence
factor. Reference the Appendix for calculations related to the MTBF value.
2.5 PVC Housing Flow
During the course of this test the PVC housing on the MaxSonar™ WR product line was
observed to cold flow. Because this test was conducted for an extended period of time in
excess of 80°C this is an expected result. Despite moderate deformation of the housing
all units continued to function normally. This is still in line with our -40°C to +65°C
(+85°C limited operation) values. It is recommended for units that will be subjected to
temperatures in excess of +80°C that these temperatures be maintained no longer than 30-
minutes for non-recurring operation and 5-minutes for recurring operation.
For more information on the effects of temperature on the stiffness of PVC reference the
Appendix.