So how long does a Revolution Pi system actually last? Well, as the saying goes: It depends….. In order to get an idea of the durability of a device, the so-called MTBF value is often used. MTBF stands for “Mean Time Between Failures“. A distinction is made here between failures that can be repaired and those that cannot.
Devices that cannot be repaired are therefore also referred to as MTTF, which stands for “Mean Time To Failure“. Colloquially, the terms are often used as synonyms, which is why “Mean Time Before Failure” is often used nowadays.
MTBF is therefore – simply spoken – a key figure that stands for the reliability of a device. The higher the MTBF value, the more reliable the device and the longer its lifespan. A device with an MTBF value of 100 hours will fail more often on average than a device with an MTBF value of 1,000 hours.
In our MTBF specifications, we have of course included the usual environmental and functional stresses, the failure criteria and the period of validity.
Under unfavorable operating conditions, significantly lower MTBF values (higher failure rates) than expected can occur, for example when used under continuous shock or at higher temperatures. Of course, the MTBF value also increases conversely when the device is used under optimum conditions, for example with regard to the room temperature etc.
MTBF value calculation
Of course, the question now arises as to how such an MTBF value is calculated. Both the mathematical determination and the application of MTBF values for reliability prediction basically assume that the Revolution Pi modules under consideration are used during their service life within their specified operating conditions. These conditions can be found in the respective technical data sheets of the products.
Failures over the life cycle follow a so-called bathtub curve. In most cases, a product fails immediately (possibly because of a manufacturing defect or a defective component) or much later after the MTBF has been reached. The MTBF also includes the FIT value.
FIT (Failures In Time) describes the expected failures for an operating time of 109 hours, which corresponds to just over 114,000 years. FIT and MTBF are linked by the formula: MTBF = 109 h/FIT
Calculated MTBF values of the Revolution Pi modules
After all the theory, we finally come to the most important part of this article: The MTBF values of our Revolution Pi modules. These are as follows (all calculations according to RDF 2000):
- At 50 °C: 516,840 hours, 59 years, 1,946 Fit
- At 65 °C: 201,480 hours, 23 years, 4,956 Fit
- At 50 °C: 315,360 hours, 36 years, 3,152 Fits
- At 65 °C: 148,920 hours, 17 years, 6,671 Fits
- At 50 °C: 337,229 hours, 38 years, 2,965 Fits
- At 65 °C: 245,307 hours, 28 years, 4,077 Fits
- At 50 °C: 1,026,987 hours, 117 years, 974 Fits
- At 65 °C: 709,462 hours, 81 years, 1,410 Fits
- At 50 °C: 813,940 hours, 93 years, 1,229 Fits
- At 65 °C: 557,512 hours, 64 years, 1,794 Fits
- At 50 °C: 962,375 hours, 110 years, 1,039 Fits
- At 65 °C: 663,105 hours, 76 years, 1,508 Fits