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What is the MTTF (Mean Time To Failure) for RM/RE encoders?

Encoder system reliability

MTTF (M) = p × t / n



installed population of readheads



average length of service



total relevant failures

From our records (yearly production figures and failure data), readhead MTTF in continuous use is 750 years.

As a practical example, if a customer has 50 machines each containing 2 encoders, the installed readhead population (p) is 100. The mean interval (t) between any readhead failure (i.e. n = 1) may be calculated by rearranging the MTTF formula:



M × n / p


750 years × 1/100


approximately 7.5 years

Therefore with a total of 100 readheads running 24 hours per day, this customer could expect a single readhead failure approximately once every 7.5 years.

This information is not a guarantee of product reliability and does not represent a condition of warranty.

Note: For RE encoders you must also take into account the bearing life which can be found in the RE datasheets.

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