HP A9834-9001B User's & Service Manual page 29

If the failure causes a transition to N- I/O or main fans in a CPU cabinet, the cabinet is immediately powered
off. If the failure causes a transition to N- I/O fans in an IOX cabinet, the I/O backplanes contained in the I/O
Chassis Enclosure (ICE) containing that fan group are immediately powered off.
Only inlet temperature increases will be monitored by HPUX, all other high temperature increase chassis
codes will not activate the envd daemon to act as configured in the /etc/envd.conf. The PM monitors ambient
(inlet) temperature. The PM polls an analog-to-digital converter to read the current ambient temperature.
The temperature falls into one of four ranges: Normal, OverTempLow, OverTempMid, or OverTempHigh. The
following state codes machine describes the actions taken based on the various temperature state transitions:
OTL_THRESHOLD = 32C -----> send error code PDC_IPR_OLT
OTM_THRESHOLD = 38C ----> send error code PDC_INT_OTM
OTH_THRESHOLD = 40C -----> shut down 48 V
NOTE In an I/O expansion (IOX) cabinet, the thresholds are set 2 degrees higher to compensate for
the fact that the cabinet sensor is mounted in a hot spot.
Chapter 1
Overview
Cooling System
29