Abstract:
A server rack includes a main body, an electronic scale, and an alarm. The main body is used for receiving a number of servers. The electronic scale includes a pressure sensor and a microcontroller. The main body presses on the pressure sensor so that the pressure sensor can measure the pressure from the main body to obtain a pressure signal. The microcontroller analyzes the pressure signal to calculating the total weight of the main body and the servers. The alarm stores a predetermined weight threshold, which is the total weight of the main body and the maximum servers that the main body can bear. The alarm also compares the measured total weight with the predetermined weight threshold. When the measured total weight is larger than the predetermined weight threshold, the alarm alarms.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to server racks, and particularly, to a server rack having a payload weighing function. 
     2. Description of Related Art 
     Server racks are used for accommodating a number of blade servers. But the load-carrying capacity of a server rack is limited. When the weight of the blade servers exceeds the load-carrying capacity of the server rack, the server rack is at risk of being damaged. 
     Therefore, it is desirable to provide a server rack, which can overcome the above-mentioned limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosures should be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. 
         FIG. 1  is a schematic view of a server rack, according to an exemplary embodiment. 
         FIG. 2  is one embodiment of a functional block diagram of the server rack of  FIG. 1 . 
         FIG. 3  is one embodiment of a schematic view of an amplifying circuit of the server rack of  FIG. 1 . 
         FIG. 4  is one embodiment of a microcontroller of the server rack of  FIG. 1 . 
         FIG. 5  is one embodiment of a display of the server rack of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1  and  FIG. 2 , a server rack  100  is used for accommodating a number of blade servers  200  and includes a main body  10 , an electronic scale  30 , a display  50 , and an alarm  70 . The display  50  and the alarm  70  are electrically connected to the electronic scale  30 . 
     The main body  10  is hollow and cuboid-shaped, and used for receiving the blade servers  200  therein. The main body  10  is positioned on a loading surface  300 , and includes a bottom surface  101  facing the loading surface  300 . Four supporting feet  11  are respectively fixed on four corners of the bottom surface  101 , and used for supporting the main body  10 . In one embodiment, the supporting feet  11  can be made of light metal. 
     The electronic scale  30  includes four pressure sensors  33 , four amplifying circuits  35 , and a microcontroller  37 . 
     Referring to  FIG. 3 , each pressure sensor  33  is positioned under a corresponding one of the supporting feet  11  to sense any loads supported by the feet  11 , and includes a first signal terminal  331  and a second signal terminal  332  used for outputting pressure signals. 
     Referring to  FIGS. 2-3 , each amplifying circuit  35  is used for amplifying the pressure signal of the corresponding pressure sensor  33 , and includes a first operational amplifier  351 , a second operational amplifier  352 , a third operational amplifier  353 , a first resistor R 1 , a second resistor R 2 , a third resistor R 3 , a fourth resistor R 4 , a fifth resistor R 5 , a sixth resistor R 6 , a seventh resistor R 7 , an eighth resistor R 8 , a first capacitor C 1 , a second capacitor C 2 , a third capacitor C 3 , and a fourth capacitor C 4 . 
     The first operational amplifier  351  includes a first negative input terminal  351   a , a first positive input terminal  351   b , and a first output terminal  351   c . The second operational amplifier  352  includes a second positive input terminal  352   a , a second negative input terminal  352   b , and a second output terminal  352   c . The third operational amplifier  353  includes a third positive input terminal  353   a , a third negative input terminal  353   b , and a third output terminal  353   c.    
     The first negative input terminal  351   a  is connected to the first signal terminal  331  through the first resistor R 1 . The first positive input terminal  351   b  is connected to the first output terminal  351   c  through the second resistor R 2 . The first output terminal  351   c  is also connected to the third negative terminal  353   b  through the third resistor R 3 . The first negative input terminal  351   a  is also connected to the first positive input terminal  351   b  through the first capacitor C 1 . The second positive input terminal  352   a  is connected to the second signal terminal  332  through the fourth resistor R 4 . The second negative output terminal  352   b  is connected to the second output terminal  352   c  through the fifth resistor R 5 . The second output terminal  352   c  is connected to the third positive input terminal  353   a  through the sixth resistor R 6 . The second positive input terminal  352   a  is connected to the second negative terminal  352   b  through the second capacitor C 2 . The third positive input terminal  353   a  is grounded through the seventh resistor R 7 . The third negative input terminal  353   a  is connected to the third output terminal  353   c  through the eighth resistor R 8 . The first positive input terminal  351   b  is also connected to the second negative input terminal  352   b  through a rheostat R 9 . The first negative input  351   a  is grounded through the third capacitor C 3 . The second positive input terminal  352   a  is grounded through the fourth capacitor C 4 . 
     The first, second, third operational amplifiers  351 ,  352 ,  353  respectively include a voltage input terminal and a voltage output terminal. The voltage input terminal is connected to a direct current power supply VCC. The voltage output terminal is grounded. In one non-limiting example, the resistance of the first resistor R 1  is equal to that of the fourth resistor R 4 . The resistance of the second resistor R 2  is equal to that of the fifth resistor R 5 . The resistance of the third resistor R 3  is equal to that of the sixth resistor R 6 . The resistance of the seventh resistor R 7  is equal to that of the eighth resistor R 8 . The capacitance of the first capacitor C 1  is equal to that of the second capacitor C 2 . The capacitance of the third capacitor C 3  is equal to that of the fourth capacitor C 4 . 
     In one embodiment, the resistances of the first resistor to the eighth resistor R 1 -R 8  respectively can be about 1KΩ, 20KΩ, 1KΩ, 1KΩ, 20KΩ, 1KΩ, 51KΩ, 51KΩ. The capacitances of the first capacitor to the fourth capacitor C 1 -C 4  respectively can be about 100 pF, 100 pF, 0.1 uF, 0.1 uF. The voltage of VCC can be about 10V. 
     The third output terminals  353   c  of the four amplifying circuits  35  respectively output an A/D 1  signal, an A/D 2  signal, an A/D 3  signal, and an A/D 4  signal. 
     Referring to  FIG. 4 , the microcontroller  37  is electrically connected to the four amplifying circuits  35  and the display  50 , and used for adding the output signals of the four amplifying circuits  35  to obtain the total weight of the main body  10  and the blade servers  200 . The microcontroller  37  includes an RA 0  terminal, an RA 1  terminal, an RA 2  terminal, an RA 3  terminal, an RC 0  terminal, an RC 1  terminal, an RC 2  terminal, an RC 3  terminal, an RC 4  terminal, an RC 5  terminal, and an RC 6  terminal. The RA 0 -RA 3  terminals are analog to digital (A/D) conversion terminals, and electrically connected to the third output terminals  353   c  of the four amplifying circuits  35 . The RC 0 -RC 6  terminals are input/output terminals, and electrically connected to the display  50 . 
     Referring to  FIG. 5 , the display  50  is positioned on the sidewall of the main body  10 , and is used for displaying the weight calculated by the microcontroller  37 . In this embodiment, the display  50  is a crystal display, and includes an LCD CON 0  terminal, an LCD CON 1  terminal, an LCD CON 2  terminal, an LCD CON 3  terminal, an LCD CON 4  terminal, an SDA terminal, and an SDL terminal. The LCD CON 1 -LCD CON 4  terminals are input/output terminals. The LCD CON 0 -LCD CON 2  terminals are respectively electrically connected to the RC 0 -RC 2  terminals of the microcontroller  37 . The LCD CON 3  terminal and the LCD CON 4  terminal are electrically connected to the RC 5  terminal and the RC 6  terminal of the microcontroller  37 . The SDA terminal is a serial data terminal. The SCL terminal is a serial clock terminal. The SDA terminal and SDL terminal are electrically connected to the RC 3  terminal and the RC 4  terminal of the microcontroller  37 . 
     Referring to  FIG. 2 , the alarm  70  is positioned on the sidewall of the main body  10 , and electrically connected to the microcontroller  37 . The alarm  70  includes a memory  71 , a comparison unit  72 , and a buzzer  73 . A predetermined weight threshold is stored in the memory  71  and represents the total weight of the main body  10  and the maximum blade servers that the main body  10  can bear. The comparison unit  72  is used for comparing the calculated weight with the predetermined weight threshold. The buzzer  73  is used for alerting users when the calculated weight is larger than the predetermined weight threshold. 
     In other embodiments, the number of the supporting feet  11  can be other than four according to practical need. In yet other embodiments, the supporting feet  11  can be omitted, and the pressure sensors  33  positioned directly under the main body  10 . The number of the pressure sensors  33  can be varied according to number and placement of supporting feet. 
     It should be noted that in any embodiments, the weight of the supporting feet  11  can be tared before use. 
     It will be understood that the above particular disclosures and methods are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous disclosures thereof without departing from the scope of the disclosure as claimed. The above-described disclosures illustrate the scope of the disclosure but do not restrict the scope of the disclosure.