Kontron AM4904, User Manual

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Operating the Unit
71 AM4904 User Guide
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The fan control module implements the following states:
Table 3-30: FAN control states
State Description Actions
Normal
The fan control is not in any
other state.
The fan level is decreased in steps of
fan_stepdown fan level steps each
fan_dec_timeout seconds down to the dynamic
fan level.
When the dynamic fan level is reached it is dec-
remented each fan_dynamic_timeout seconds
until fan_norm_level is reached.
Minor
The fan control is not in critical
and error state and
at least one temperature sen-
sor reports that the upper non-
critical threshold has been
crossed.
If the current fan level is equal the dynamic fan
level and the previous state was normal then
the dynamic fan level is increased by one.
The current fan level is increased in steps of
fan_stepup fan level steps each
fan_inc_timeout seconds until the maximum
fan level is reached.
Critical
The fan control is not in error
state and at least one tempera-
ture sensor reports that the
upper critical or upper non-
recoverable threshold has been
crossed.
If the current fan level is equal the dynamic fan
level and the previous state was normal then
the dynamic fan level is increased by one.
The current fan level is set to the maximum
value.
Error
At least one of the cooling
units is not in M4 or M5 state or
the fan control module has not
been discovered all cooling
units or the fan control is not
able to adjust the speed of a
cooling unit.
The fan level is set to the maximum value until
this state is left.