Article ID: 11184
Explain the temperature requirements of the D-Series product line.
The Installation Guide
provides these statements of fact:
The D2 fan is designed to run extremely quiet and is only required to operate beyond
temperatures of 40 degrees C (104 degrees F) on the non-PoE model and 35 degrees C (95
degrees F) on the PoE model.
. . .
Note: The D2 fan will turn on when power is first supplied to the switch and will shut off
automatically when the temperature falls below the following switch thresholds:
* D2G124-12 - 40 degrees C (104 degrees F)
* D2G124-12P - 35 degrees C (95 degrees F)
. . .
Operating Temperature * D2G124-12 - 0C to 60C (32F to 140F)
* D2G124-12P - 0C to 50C (32F to 122F)[/code]
The firmware 1.00.03.0002 Release Notes
provides this statement of fact:
The following changes were made to the temperature trip points for fan operation:
* D2G124-24P - Fans turn on when Sensor 1 temperature reads >= 65C
* D2G124-24 - Fans turn on when Sensor 1 temperature reads >= 69C.
* Fans will continue to turn on if Sensor 2 in either model reaches 60C.[/code]
These sets of documentation only appear
to conflict with each other.
The "operating temperatures" are the ambient (room) temperature ranges supported for the proper operation of the switch.
The others represent internal temperatures. The D-Series switch turns fans on for internal cooling as needed for normal operation, but does not have external temperature sensors. These temperatures are taken from sensors located on internal circuitry, and only seem high because under normal operation the internal temperatures are higher than temperatures external to the switch.
Operating Temperature D2G124-12 - 0C to 60C (32F to 140F)
(ambient) D2G124-12P - 0C to 50C (32F to 122F)
Fans Running D2G124-12 - 69C and higher (156F and higher)
(internal) D2G124-12P - 65C and higher (149F and higher)[/code]
Though ambient temperature cannot be directly measured, the fan activation point has been tested to assure that the fans are kicking on at roughly 40C (104F) ambient for the D2G124-12 and 35C (95F) ambient for the D2G124-12P.
The fans run when power is first supplied to the switch to demonstrate that the fans work, and then shut off automatically until needed for cooling purposes.
See also: 11747