Midplane Temperature Sensing for Stable Disk Drive Cooling Control
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Solution Overview
Problem
Data storage systems face challenges in accurately measuring temperature due to preheated air streams affecting sensor readings and potential false data from faulty sensors, leading to hysteresis and inefficient fan speed control.
Innovation Solution
A method involving multiple temperature sensors on a midplane to detect and compare temperature signals, selecting the most accurate signal to control fan speed and identify faulty sensors, ensuring reliable temperature control and minimizing hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple temperature sensors are used to detect temperature in preheated air streams, then backup information is available for sensor failure, but false sensor readings complicate the control algorithm
Solution Approach 1:
The system performs preliminary actions by continuously monitoring all temperature sensors and pre-identifying faulty sensors before they cause control problems. The microprocessor compares temperature readings from multiple sensors and proactively identifies which sensor has failed, allowing the system to switch to using only healthy sensor data without disruption to the cooling control function.
2Temperature
If fan speed is increased to cool the system, then cooling effectiveness improves, but the sensor to ambient temperature difference decreases causing hysteresis
Solution Approach 1:
The system uses feedback by continuously monitoring the temperature sensor readings and comparing them against expected values based on fan speed and ambient conditions. When a sensor reading deviates significantly from the expected range (indicating the sensor is measuring preheated air rather than ambient air), the system adjusts its control strategy to account for this feedback, preventing hysteresis and improving temperature control stability.
3Ease of manufacture
If temperature sensors are located on the first available PCB in the system, then installation is simplified, but the sensors are located in air streams preheated by upstream electronics
Solution Approach 1:
The system segments the temperature measurement function by using multiple temperature sensors distributed at different locations in the air flow path. Rather than relying on a single sensor that may be in preheated air, the system divides the measurement task across several sensors, allowing it to identify and select readings from sensors that are positioned in cooler, more representative locations.
4Device complexity
If a single temperature sensor is used, then the system is simpler, but the system shuts down for lack of information when the sensor fails
Solution Approach 1:
The system applies local quality by assigning different roles to different sensors based on their performance. Rather than treating all sensors equally or requiring a complex redundant system, the microprocessor dynamically evaluates each sensor's readings and identifies which sensor is functioning correctly. The system then locally adapts by using only the reliable sensor data for control decisions, maintaining simplicity while ensuring reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of temperature measurement and fan speed control, reducing noise and power consumption while preventing system damage from excessive temperatures.
Implementation Method 1
The midplane has a plurality of temperature sensors mounted thereto, such plurality of temperature sensors being disposed to detect the temperature of the air flow passing through the channels
Implementation Method 2
The fan has the speed thereof controlled in response to a temperature control signal. The method includes: detecting temperature signals produced by the plurality of temperature sensors; comparing differences between the detected temperature signals; and selecting one of the detected temperature control signals from the compared differences as the temperature control signal
Data Source
AI summary
A system having: a midplane having air flow channels therein; a disk drive mounted to a first side of the midplane; and a temperature sensors mounted to the midplane. The system includes a pair of electrical chassis connected to a second side of the midplane. A first one of the chassis has therein: a fan; and a fan controller for controlling speed of the fan in response to a temperature control signal. A second one of the chassis has therein: a microprocessor for: detecting temperature signals produced by the temperature sensors; comparing differences between the detected temperature signals; and selecting one of the detected temperature control signal from the compared differences as the temperature control signal. A faulty one of the temperature sensors is detected by: selecting one of the detected temperature control signal as the faulty one of the plurality of temperature sensors from the compared differences.