Server Fan Control With BMC Failure Detection
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Solution Overview
Problem
Existing server fan control systems fail to maintain normal operation when the baseboard management controller (BMC) malfunctions, leading to potential overheating and shutdown due to abnormal fan behavior.
Innovation Solution
A control module is introduced between the BMC and the fan to detect abnormal states by monitoring PWM signals, ensuring the fan continues to operate with a preset signal when the BMC is malfunctioning, thereby maintaining heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the BMC uses PWM signals to control fan speed, then the fan speed can be adjusted to maintain server temperature, but when the BMC malfunctions, the fan may stop or work abnormally leading to overheating
Solution Approach 1:
A control module is introduced as an intermediary between the BMC and the fan. This control module receives PWM signals from the BMC, monitors their validity, and outputs controlled signals to the fan. When the BMC malfunctions or outputs abnormal signals, the control module detects this and activates a preset PWM signal to ensure the fan continues to operate reliably, preventing overheating while maintaining system temperature control.
2Adaptability or versatility
If the system relies solely on BMC for fan control, then the control system is simple, but the system fails to respond to BMC abnormalities
Solution Approach 1:
The control module continuously monitors the PWM signals from the BMC and provides feedback on their validity. It detects abnormalities such as invalid PWM signals or failures in PWM output and responds by switching to a preset PWM signal to control the fan. This feedback mechanism enables the system to adapt to BMC abnormalities and maintain reliable fan operation without requiring complex additional hardware.
Data Source
AI summary
A system for maintaining the operation of a cooling fan for a server if that function of a baseboard management controller (BMC) of the server should fail includes the BMC and a control module. The control module is electrically connected to the BMC and the fan, and the control module receives a first signal outputted by the BMC in a cycle and determines the state of the BMC depending on whether the first signal includes a change in level or fails to include a change in level. When an abnormal state of the BMC is determined, the control module outputs a preset pulse width modulation (PWM) signal to the fan to maintain operation of the fan.