Artesyn System Management Interface Based on HPI-B (Centellis 2000 R3.0/4411) User's Guide (June 2014) - Manual (Page 77)

Using HPI-B
System Management Interface Based on HPI-B (Centellis 2000 R3.0/4411) User’s Guide (6806800P20C) 77
4.6 Cooling Management
As mentioned earlier, the HPI daemon software of the ATCA-MF106/SAM1411 performs shelf
management functions. One of the most important functions is cooling management. Details
are given in the following sections.
4.6.1 Cooling Management Performed by ATCA-MF106/SAM1411
Cooling management as performed by the ATCA-MF106/SAM1411 HPI daemon software
includes the monitoring of operating temperatures within a shelf, and depending on the data
obtained, controlling the cooling fans in order to ensure proper cooling of all components in a
shelf. Apart from proper cooling, another important goal of cooling management is to keep the
noise caused by the fans to a minimum. This is important to meet NEBS requirements.
4.6.1.1 Basic Functionality
For the cooling management, the software considers all IPMI temperature sensors in the shelf.
This includes sensors on FRUs, such as blades and AMC modules, but also inlet/outlet sensors
of the shelf. The latter are combined to a single virtual difference sensor.
After system start-up, the fans are operated at minimum speed and the shelf management
software starts to monitor all temperature sensors.
As soon as a sensor reaches or exceeds the upper minor threshold, the software initializes and
starts a virtual Proportional-Integral-Derivative (PID) controller for the respective sensor. The
PID uses the current sensor temperature as input and the fan control level as output. In the case
of the virtual difference sensor, the input is a predefined air difference temperature profile. The
algorithm used within the PID keeps the measured temperature at the upper minor threshold.