What changed in the Fan Control for the M9502A and M9505A with firmware 1.3.23?

The initial release of the M9502A/M9505A firmware (1.3.8) allowed a minimum fan speed parameter to be set between 8-15. The 8 corresponded to about 35% of max speed and the 15 corresponded to 100% of max speed. The 8-15 numbers did not convey a very clear understanding of the speed so the programming range was changed to be a percent of full speed.

Starting with the Dec 2011 M9502A/M9505A firmware (1.3.23) the minimum fan speed parameter is now set between 35-100. The 35 represents 35% of max speed, and the 100 represents 100% of max speed.

The fan speed on a M9502A/M9505A will vary from the minimum set value up to the maximum value based on the temperature exhausting from the slots. The maximum value is not settable.

The firmware in the M9502A/M9505A has a part that is located on the backplane of the chassis and a part that is located in the ESM which is below slot 1. When new firmware is downloaded into the M9502A/M9505A both the Chassis component and the ESM component are updated.

If a ESM from another chassis or a new ESM is installed during a repair process the possibility exists of creating the situation in which the backplane Chassis component of the firmware is not compatible with the ESM component of the firmware. This should be corrected by installing the latest firmware which will make the backplane component compatible with the ESM component.

If an old firmware revision ESM (1.3.8) is placed into a newer chassis (1.3.23) then the chassis understands (35-100) but the ESM understands (8-15) and the end result will be that the ESM sends the chassis (8-15) which the chassis will round up to the minimum 35. Thus the only settable speed is the minimum.

If old Chassis component firmware is used with a new ESM component then a “UPDATEFW” will be concatenated at the end of the Firmware revision string. The fan speed parameter will be 6-15.

Note: 6 is lower than normal (8-15) and this may cause the fan status to say “Lower Non-Critical” because the speed is so slow. The Ekey links page will not have correct information.

If incorrect fan behavior is suspected, then look at the Firmware revision string.

Firmware 1.3.8 should only be found with Chassis component 0103.

Firmware 1.3.23 should only be found with Chassis component 0107.

If the wrong Chassis or ESM component is found for the Firmware revision then the firmware needs to be re-installed to make them be compatible.

Following are screen captures that show good installations and what happens when the Chassis and ESM components are mis-matched.