7.5Environmental limits
Temperature and humidity values experienced by the drive must be such that condensation does not occur on any drive part. Altitude and atmospheric pressure specifications are referenced to a standard day at 58.7°F (14.8°C). Maximum wet bulb temperature is 82°F (28°C).
7.5.1Temperature a. Operating
The drive meets the operating specifications over a 41°F to 140°F (5°C to 60°C) drive case temperature range with a maximum temperature gradient of 36°F (20°C) per hour.
The maximum allowable drive case temperature is 60°C. See Figure 4 for HDA case temperature measurement location.
The MTBF specification for the drive assumes the operating environment is designed to maintain nominal case temperature. The rated MTBF is based upon a sustained case temperature of 104°F (40°C). Occasional excursions in operating temperature between the rated MTBF temperature and the maximum drive operating case temperature may occur without impact to the rated MTBF temperature. However, continual or sustained operation at case temperatures beyond the rated MTBF temperature will degrade the drive MTBF and reduce product reliability.
Air flow may be required to achieve consistent nominal case temperature values (see Section 11.2). To confirm that the required cooling is provided for the electronics and HDA, place the drive in its final mechanical configuration, and perform random write/read operations. After the temperatures stabilize, measure the case temperature of the drive.
b.
HDA Temp.
Check Point
Figure 4. Location of the HDA temperature check point
Note. Image is for reference only, may not represent actual drive.
7.5.2Relative humidity
The values below assume that no condensation on the drive occurs.
a.Operating
5% to 95%
b.
5% to 95%
28 | Constellation ES.2 SAS Product Manual, Rev. D |
