Abstract:
Embodiments of the present invention disclose a module supporting hot plug, a backplane, a system comprising the module and the backplane, and a method for determining connection of the module with the backplane. The module may comprise a first connector comprising a first array of pins, and the backplane may comprise a second connector comprising a second array of pins corresponding to the first array of pins. A portion of the pins of the first array may be selected such that connection of the module with the backplane can be determined based on connection of the selected pins of the first array with corresponding pins of the second array. According to the embodiments of the present invention, the module will be enabled to work only after all the pins are effectively connected to the corresponding pins of the backplane. Thus, no invalid data will be transmitted to the field devices or controller. The hot plug function can be implemented without any extra components and without needing any extra operations from users.

Description:
TECHNICAL FIELD 
       [0001]    Embodiments of the present invention relate to the field of automatic control, and more particularly, relate to a module supporting hot plug, a backplane, a system comprising the module and the backplane, and a method for determining connection of the module with the backplane. 
       BACKGROUND ART 
       [0002]    A discrete control system (DCS) is a kind of automatic control system in which one or more computers are employed to control a plurality of control loops in a process of manufacturing and so on. In the DCS, in order to achieve the extendibility of the system, it is desired to allow one or more modules, such as an I/O module, a main control module, a data forwarding module and the like, to be added to or removed from a backplane provided in a running DCS, i.e., to achieve hot plug of modules. 
         [0003]    The module typically comprises a connector for connecting the module to a backplane. An array of pins may be arranged on the connector of the module. Likewise, the backplane typically comprises a connector having an array of pins corresponding to the array of pins of the module. The array of pins of the module is mated with the array of pins of the backplane such that the module is connected to the backplane. Optionally, a Micro Controller Unit (MCU) may be connected to the connector of the module or to the connector of the backplane so as to control the module. In the array of pins of the module, some pins are used for powering the MCU, and others are to be used by field devices. In a process of connecting the module to the backplane, if the pins for the MCU are effectively connected to corresponding pins of the backplane while the pins for the field devices are not effectively connected to corresponding pins of the backplane, the MCU may work well, but control of the field devices get lost. Thus, invalid data may be transmitted to the field devices or to a controller. In order to avoid problems like this, it should better be ensured that the MCU knows whether all pins/as many pins as possible of the module are effectively connected to the backplane and enables the module based on a correct connection of the module. 
         [0004]    In the prior art, special hot plug ICs or special connectors or mechanical switches are used for making it sure that power is off before the module is connected to or removed from the backplane. These prior art solutions can realize the hot plug function, but the special hot plug ICs are quite expensive and the mechanical switches require additional operations from users during hot plug. 
       SUMMARY OF INVENTION 
       [0005]    In view of the foregoing, one or more of the objectives of embodiments of the present invention is to propose a new hot plug solution so as to solve or at least partially mitigate at least part of problems in the prior art. 
         [0006]    According to a first aspect of embodiments of the present invention, there is provided a module supporting hot plug. The module can comprise a connector for connecting the module to a backplane. The connector comprises an array of pins, wherein a portion of the pins of the array are selected such that connection of the module with the backplane can be determined based on connection of the selected pins with the backplane. 
         [0007]    According to an exemplary embodiment, the selected pins are configured such that once the selected pins are effectively connected to the backplane, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the backplane can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. 
         [0008]    According to an exemplary embodiment, the selected pins can comprise at least three pins which are located at or in close proximity to a periphery of the connector. 
         [0009]    According to an exemplary embodiment, the selected pins can comprise at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array, respectively. According to an exemplary embodiment, the selected pins can further comprise at least one pin which is located between the pins which are located at or in close proximity to the upper left and lower left corners, or between the pins which are located at or in close proximity to the lower right and upper right corners. 
         [0010]    According to an exemplary embodiment, the module can further comprise a Micro Controller Unit (MCU) connected to the connector and configured to determine, based on the determined connection of the module with the backplane, whether the module should be enabled. 
         [0011]    According to an exemplary embodiment, one of the selected pins is connected to a power source via a first resister and to the MCU, and another one of the selected pins is connected to the ground. 
         [0012]    According to an exemplary embodiment, one of the selected pins is connected to the ground via a second resister and to the MCU, and another one of the selected pins is connected to a power source. 
         [0013]    According to a second aspect of embodiments of the present invention, there is provided a backplane. The backplane can comprise a first connector being configured to be used in conjunction with a second connector of a module supporting hot plug. The second connector comprises an array of pins. The first connector comprises an array of pins corresponding to the array of pins of the second connector. A portion of the pins of the array of the first connector can be selected such that connection of the module with the backplane can be determined based on connection of the selected pins of the first connector with corresponding pins of the second connector. 
         [0014]    According to an exemplary embodiment, the selected pins are configured such that once the selected pins are effectively connected to the corresponding pins of the second connector, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the corresponding pins of the second connector can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. 
         [0015]    According to an exemplary embodiment, the selected pins can comprise at least three pins which are located at or in close proximity to a periphery of the first connector. 
         [0016]    According to an exemplary embodiment, the selected pins can comprise at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array of the first connector, respectively. According to an exemplary embodiment, the selected pins can further comprise at least one pin which is located between the pins which are located at or in close proximity to the upper left and lower left corners, or between the pins which are located at or in close proximity to the lower right and upper right corners. 
         [0017]    According to an exemplary embodiment, the backplane can further comprise a Micro Controller Unit (MCU) connected to the first connector. 
         [0018]    According to an exemplary embodiment, one of the selected pins is connected to a power source via a third resister and to the MCU, and another one of the selected pins is connected to the ground. 
         [0019]    According to an exemplary embodiment, one of the selected pins is connected to the ground via a fourth resister and to the MCU, and another one of the selected pins is connected to a power source. 
         [0020]    According to a third aspect of embodiments of the present invention, there is provided a method for determining connection of a module with a backplane. The module can comprise a first connector comprising an array of pins, and the backplane can comprise a second connector comprising an array of pins corresponding to the array of pins of the first connector. The method can comprise selecting a portion of the pins of the first connector, connecting the first connector to the second connector, detecting whether the selected pins are effectively connected to corresponding pins of the second connector, and determining whether the module is effectively connected to the backplane based on the detecting. 
         [0021]    According to an exemplary embodiment, the method can further comprise: configuring the selected pins such that once the selected pins are effectively connected to the backplane, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the backplane is detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane is determined based on the signal. 
         [0022]    According to an exemplary embodiment, selecting a portion of the pins of the first connector comprises selecting at least three pins which are located at or in close proximity to a periphery of the first connector. 
         [0023]    According to an exemplary embodiment, selecting a portion of the pins of the first connector comprises selecting at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the first connector, respectively. 
         [0024]    According to an exemplary embodiment, the method can further comprise: connecting one of the four selected pins to a power source via a first resister and to a MCU, connecting another one of the four selected pins to the ground, short-circuiting the remaining two of the four selected pins with each other, short-circuiting the pin of the second connector corresponding to the one of the four selected pins with the pin of the second connector corresponding to one of the remaining two of the four selected pins, and short-circuiting the pin of the second connector corresponding to the another one of the four selected pins with the pin of the second connector corresponding to the other of the remaining two of the four selected pins. Detecting whether the four selected pins are effectively connected to the corresponding pins comprises detecting a voltage at the one of the four selected pins with the MCU. Determining whether the module is effectively connected to the backplane based on the detecting comprises determining the module is effectively connected to the backplane if the detected voltage is equal to zero, or determining the module is not effectively connected to the backplane if the detected voltage is equal to the voltage supplied by the power source. 
         [0025]    According to an exemplary embodiment, the method can further comprise: connecting one of the four selected pins to the ground via a second resister and to a MCU, connecting another one of the four selected pins to a power source, short-circuiting the remaining two of the four selected pins with each other, short-circuiting the pin of the second connector corresponding to the one of the four selected pins with the pin of the second connector corresponding to one of the remaining two of the four selected pins, short-circuiting the pin of the second connector corresponding to the another one of the four selected pins with the other of the remaining two of the four selected pins. Detecting whether the four selected pins are effectively connected to the corresponding pins of the second connector comprises detecting a voltage at the one of the four selected pins with the MCU. Determining whether the module is effectively connected to the backplane based on the detecting comprises determining the module is effectively connected to the backplane if the detected voltage is equal to the voltage supplied by the power source, or determining the module is not effectively connected to the backplane if the detected voltage is equal to zero. 
         [0026]    According to a fourth aspect of embodiments of the present invention, there is provided a system comprising a module supporting hot plug and a backplane. The module comprises a first connector comprising a first array of pins, and the backplane comprises a second connector comprising a second array of pins corresponding to the first array of pins. A portion of the pins of the first array are selected such that connection of the module with the backplane can be determined based on connection of the selected pins of the first array with corresponding pins of the second array. 
         [0027]    According to an exemplary embodiment, the selected pins of the first array and corresponding pins of the second array can be configured such that once the selected pins of the first array are effectively connected to the corresponding pins of the second array, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the corresponding pins of the second array can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. 
         [0028]    According to an exemplary embodiment, the selected pins can comprise at least three pins which are located at or in close proximity to a periphery of the first array. 
         [0029]    According to an exemplary embodiment, the selected pins can comprise at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the first array, respectively. 
         [0030]    According to an exemplary embodiment, the selected pins can further comprise at least one pin which is located between the pins which are located at or in close proximity to the upper left and lower left corners of the first array, or between the pins which are located at or in close proximity to the lower right and upper right corners of the first array. 
         [0031]    According to an exemplary embodiment, the system can further comprise a Micro Controller Unit (MCU) connected to the first connector and configured to determine, based on the determined connection of the module with the backplane, whether the module should be enabled. In this embodiment, one of the selected pins is connected to a power source via a first resister and to the MCU, and another one of the selected pins is connected to the ground. Alternatively, one of the selected pins is connected to the ground via a second resister and to the MCU, and another one of the selected pins is connected to a power source. 
         [0032]    According to an exemplary embodiment, the system can further comprise a Micro Controller Unit (MCU) connected to the second connector. In this embodiment, one of the pins of the second array corresponding to the selected pins of the first array is connected to a power source via a third resister and to the MCU, and another one of the pins of the second array corresponding to the selected pins of the first array is connected to the ground. Alternatively, one of the pins of the second array corresponding to the selected pins of the first array is connected to the ground via a fourth resister and to the MCU, and another one of the pins of the second array corresponding to the selected pins of the first array is connected to a power source. 
         [0033]    According to an exemplary embodiment, the selected pins comprise a first pair of pins and a second pair of pins and the corresponding pins of the second array comprise a third pair of pins and a fourth pair of pins corresponding to the first pair of pins and the second pair of pins respectively. One of the first pair of pins is short-circuited with the other of the first pair of pins while one of the third pair of pins is short-circuited with one of the fourth pair of pins and the other one of the third pair of pins is short-circuited with the other one of the fourth pair of pins. 
         [0034]    According to the solutions of the embodiments of the present invention, the module will be enabled to work only after all the pins are effectively connected to the corresponding pins of the backplane. Thus, no invalid data will be transmitted to the field devices or controller. With the solutions of the embodiments of the present invention, the hot plug function can be implemented without any extra components and without needing any extra operations from users. 
         [0035]    Other features and advantages of the embodiments of the present invention will also be apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0036]    Embodiments of the invention are presented in the sense of examples and their advantages are explained in greater detail below, with reference to the accompanying drawings, wherein 
           [0037]      FIG. 1  schematically illustrates a diagram of a module supporting hot plug according to a first embodiment of the first aspect of embodiments of the present invention; 
           [0038]      FIG. 2  schematically illustrates a diagram of a module supporting hot plug according to an example of a second embodiment of the first aspect of embodiments of the present invention; 
           [0039]      FIG. 3  schematically illustrates a diagram of a module supporting hot plug according to anther example of the second embodiment of the first aspect of embodiments of the present invention; 
           [0040]      FIG. 4  schematically illustrates a diagram of a module supporting hot plug according to a yet another example of the second embodiment of the first aspect of embodiments of the present invention; 
           [0041]      FIG. 5  schematically illustrates a diagram of a module supporting hot plug according to a third embodiment of the first aspect of embodiments of the present invention; 
           [0042]      FIG. 6  schematically illustrates a diagram of a module supporting hot plug according to an example of a fourth embodiment of the first aspect of embodiments of the present invention; 
           [0043]      FIG. 7  schematically illustrates a diagram of a module supporting hot plug according to an example of a fifth embodiment of the first aspect of embodiments of the present invention; 
           [0044]      FIG. 8  schematically illustrates a diagram of a backplane according to a first embodiment of the second aspect of embodiments of the present invention; 
           [0045]      FIG. 9  schematically illustrates a diagram of a backplane according to an example of a second embodiment of the second aspect of embodiments of the present invention; 
           [0046]      FIG. 10  schematically illustrates a diagram of a backplane according to anther example of the second embodiment of the second aspect of embodiments of the present invention; 
           [0047]      FIG. 11  schematically illustrates a diagram of a backplane according to a yet another example of the second embodiment of the second aspect of embodiments of the present invention; 
           [0048]      FIG. 12  schematically illustrates a diagram of a backplane according to a third embodiment of the second aspect of embodiments of the present invention; 
           [0049]      FIG. 13  schematically illustrates a diagram of a backplane according to an example of a fourth embodiment of the second aspect of embodiments of the present invention; 
           [0050]      FIG. 14  schematically illustrates a diagram of a backplane according to an example of a fifth embodiment of the second aspect of embodiments of the present invention; 
           [0051]      FIG. 15  illustrates a flow chart of a method for determining connection of a module with a backplane according to an embodiment of the present invention; and 
           [0052]      FIG. 16  illustrates a diagram of the module supporting hot plug as shown in  FIG. 6  and a backplane to be used in conjunction therewith. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0053]    It should be appreciated that, while this specification contains many specific implementation details, they should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
         [0054]    In a first aspect of embodiments of the present invention, there is provided a module supporting hot plug. Hereinafter, reference will be made to  FIGS. 1 to 7  to describe the module supporting hot plug according to the first aspect of the embodiments of the present invention. 
         [0055]      FIG. 1  schematically illustrates a diagram of a module supporting hot plug according to a first embodiment of the first aspect of the embodiments of the present invention. The module may be, for example, an I/O module, a main control module, a data forwarding module and the like. The backplane may be, for example, arranged in an I/O station of the DCS. The present invention may be applied to any module and backplane having a hot plug function. 
         [0056]    As shown in  FIG. 1 , a module supporting hot plug  10  comprises a connector  11  for connecting the module  10  to a backplane (not shown). The connector  11  comprises an array of pins  12 . The pins may be male or female ones. The array  12  may comprises m rows×n columns of pins. Although it is schematically shown in  FIG. 1  that the array  12  comprises 4 columns of pins, it will be understood that the number of the column of pins may have any suitable value, such as 2, 3, etc. Likewise, the number of the row of pins may have any suitable value, such as 36. According to the embodiments of the present application a portion of the pins of the array  12  are selected such that connection of the module  10  with the backplane can be determined based on connection of the selected pins with the backplane. 
         [0057]    In the second embodiment of the module supporting hot plug according to the present invention, the selected pins are configured such that once the selected pins are effectively connected to the backplane, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the backplane can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. 
         [0058]    It will be noted that, for the purpose of clarity, the selected pins of the connector of the module are represented by circles filled with black “•” in  FIGS. 2-7 . 
         [0059]    According to an example of the second embodiment of the module supporting hot plug, the selected pins can comprise at least three pins which are located at or in close proximity to a periphery of the connector, as schematically shown in  FIG. 2 . In  FIG. 2 , a module supporting hot plug  20  comprises a connector  21  for connecting the module  20  to a backplane (not shown). The connector  21  comprises an array of pins  22 . The selected pins comprise three pins  221 - 223  which are located in close proximity to a periphery of the connector  21 . Alternatively, the three selected pins  221 - 223  may be located at the periphery of the connector  21 . Preferably, the three selected pins  221 - 223  are located at different side of the connector  21 , for example, top, left and bottom respectively, or in close proximity to different side of the connecter; and/or are spaced apart from each other as far as possible. 
         [0060]    According to another example of the second embodiment of the module supporting hot plug, the selected pins comprises at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array, respectively, as schematically shown in  FIG. 3 . In  FIG. 3 , a module supporting hot plug  30  comprises a connector  31  for connecting the module  30  to a backplane (not shown). The connector  31  comprises an array of pins  32 . The selected pins comprise four pins  321 - 324  which are located in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  32 , respectively. Alternatively, the four selected pins  321 - 324  may be located at an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  32 , respectively. 
         [0061]    In order to improve the accuracy in determining the connection of the module with the backplane based on the connection of the selected pins with the backplane, according to yet another example of the second embodiment of the module supporting hot plug, the selected pins further comprise at least one pin which is located between the pins which are located at or in close proximity to the upper left and lower left corners, or between the pins which are located at or in close proximity to the lower right and upper right corners, as schematically shown in  FIG. 4 . In  FIG. 4 , a module supporting hot plug  40  can comprise a connector  41  for connecting the module  40  to a backplane (not shown). The connector  41  comprises an array of pins  42 . Besides the four pins  421 - 424  which are located in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  42 , the selected pins further comprise a pin  425  located between the pins  423  and  424 . Alternatively, the pin  425  may be located between the pins  421  and  422 . 
         [0062]    In a third embodiment of the module supporting hot plug according to the present invention, the module further comprises a MCU connected to the connector. In this embodiment, the selected pins of the connector are configured such that once the selected pins are effectively connected to the backplane, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the backplane can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. The MCU is configured to determine, based on the determined effective connection of the module with the backplane, the module should be enabled. Otherwise, the MCU will determine the module should not be enabled. 
         [0063]      FIG. 5  schematically illustrates a diagram of a module supporting hot plug according to the third embodiment. In  FIG. 5 , a module supporting hot plug  50  can comprise a connector  51  for connecting the module  50  to a backplane (not shown) and a MCU  53  connected to the connector  51 . The connector  51  comprises an array of pins  52 . The MCU  53  is configured to determine, based on the determined connection of the module  50  with the backplane, whether the module  50  should be enabled. It should be understood that the connector  51  can be implemented with any one of the connectors as shown in  FIGS. 1-4 . 
         [0064]    In a fourth embodiment of the module supporting hot plug according to the present invention, the module further comprises, besides the MCU as described in the third embodiment, a power source for powering the module. In this embodiment, one of the selected pins is connected to the power source via a first resister and to the MCU, and another one of the selected pins is connected to the ground. 
         [0065]      FIG. 6  schematically illustrates a diagram of a module supporting hot plug according to an example of the fourth embodiment. In  FIG. 6 , a module supporting hot plug  60  comprises a connector  61  for connecting the module  60  to a backplane (not shown), a MCU  63  and a power source  64 . The connector  61  comprises an array of pins  62 . Pins  621 - 624  of the array  62  are selected such that connection of the module  60  with the backplane can be determined based on connection of the selected pins  621 - 624  with the backplane. The pin  621  is connected to the power source  64  via a resister  65  and to the MCU  63 , the pin  622  is connected to the ground and the pin  623  is short-circuited with the pin  624 . 
         [0066]    In a fifth embodiment of the module supporting hot plug according to the present invention, the module further comprises, besides the MCU as described in the third embodiment, a power source for powering the module. In this embodiment, one of the selected pins is connected to the ground via a second resister and to the MCU, and another one of the selected pins is connected to the power source. 
         [0067]      FIG. 7  schematically illustrates a diagram of a module supporting hot plug according to an example of a fifth embodiment of the first aspect of the present invention. In  FIG. 7 , a module supporting hot plug  70  comprises a connector  71  for connecting the module  70  to a backplane (not shown), a MCU  73  and a power source  74 . The connector  71  comprises an array of pins  72 . Pins  721 - 724  of the array  72  are selected such that connection of the module  70  with the backplane can be determined based on connection of the selected pins  721 - 724  with the backplane. The pin  721  is connected to the ground via a resister  75  and to the MCU  73 , the pin  722  is connected to the power source  74  and the pin  723  is short-circuited with the pin  724 . 
         [0068]    In a second aspect of embodiments of the present invention, there is provided a backplane. Hereinafter, reference will be made to  FIGS. 8 to 15  to describe the backplane according to the second aspect of the present invention. 
         [0069]      FIG. 8  schematically illustrates a diagram of a backplane according to a first embodiment of the second aspect of embodiments of the present invention. As shown in  FIG. 8 , a backplane  80  comprises a connector  81 . The connector  81  is configured to be used in conjunction with a connector of a module supporting hot plug, such as one of the connectors as described with reference to  FIGS. 1-7 . As described above, the connector of the module supporting hot plug, such as the connector  11 ,  21 ,  31 ,  41 ,  51 ,  61  or  71  as shown in  FIGS. 1-7 , respectively, comprises an array of pins. The connector  81  comprises an array of pins  82  corresponding to the array of pins of the connector of the module. The pins  82  may be male or female ones. A portion of the pins of the array of the connector  81  are selected such that connection of the module with the backplane  80  can be determined based on connection of the selected pins of the connector  81  with corresponding pins of the connector of the module. 
         [0070]    In a second embodiment of the backplane according to the present invention, the selected pins of the connector  81  are configured such that once the selected pins are effectively connected to the corresponding pins of the connector of the module, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the corresponding pins of the connector of the module can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. 
         [0071]    It will be noted that, for the purpose of clarity, the selected pins of the connector of the backplane are represented by circles “o” in  FIGS. 9-15 . 
         [0072]    As an example of the second embodiment of the backplane, the selected pins comprises at least three pins which are located at or in close proximity to a periphery of the connector of the backplane, as schematically shown in  FIG. 9 . In  FIG. 9 , a backplane  90  comprises a connector  91  for connecting the module to the backplane  90 . The module may be, for example, any one of the modules as shown in  FIGS. 1-8 . The connector  91  comprises an array of pins  92 . The selected pins comprise three pins  921 - 923  which are located in close proximity to a periphery of the connector  21 . Alternatively, the three selected pins  921 - 923  may be located at the periphery of the connector  91 . Preferably, the three selected pins  921 - 923  are located at different side of the connector  91 , for example, top, left and bottom respectively, or in close proximity to different side of the connecter; and/or are spaced apart from each other as far as possible. 
         [0073]    As another example of the second embodiment of the backplane, the selected pins comprises at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array, respectively, as schematically shown in  FIG. 10 . In  FIG. 10 , a backplane  100  comprises a connector  101  for connecting the module to the backplane  100 . The connector  101  comprises an array of pins  102 . The selected pins comprise four pins  1021 - 1024  which are located in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  102 , respectively. Alternatively, the four selected pins  1021 - 1024  may be located at an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  102 , respectively. The module may be, for example, the module  30  as shown in  FIG. 3 . 
         [0074]    As yet another example of the second embodiment of the backplane, the selected pins can further comprise at least one pin which is located between the pins which are located at or in close proximity to the upper left and lower left corners, or between the pins which are located at or in close proximity to the lower right and upper right corners, as schematically shown in  FIG. 11 . In  FIG. 11 , a backplane  110  comprises a connector  111  for connecting the module to the backplane  110 . The module may be, for example, any one of the modules as shown in  FIGS. 1-8 . The connector  111  comprises an array of pins  112 . Besides the four pins  1121 - 1124  which are located in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  112 , the selected pins also comprises a pin  1125  located between the pins  1123  and  1124 . Alternatively, the pin  1125  may be located between the pins  1121  and  1122 . 
         [0075]    In a third embodiment of the backplane according to the present invention, the backplane further comprises a MCU connected to the connector of the backplane. In this embodiment, the selected pins of the connector of the backplane are configured such that once the selected pins are effectively connected to the corresponding pins of the connector of the module, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the corresponding pins of the connector of the module can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. 
         [0076]      FIG. 12  schematically illustrates a diagram of a backplane according to the third embodiment. In  FIG. 12 , a backplane  120  comprises a connector  121  for connecting a module (not shown) to a backplane  120  and a MCU  123  connected to the connector  121 . The module may be, for example, any one of the modules as shown in  FIGS. 1-4 . The connector  121  comprises an array of pins  122 . It should be understood that the connector  121  can be implemented with any one of the connectors as shown in  FIGS. 8-11 . 
         [0077]    In a fourth embodiment of the backplane according to the present invention, one of the selected pins of the connector of the backplane is connected to a power source via a third resister and to the MCU, and another one of the selected pins is connected to the ground. 
         [0078]      FIG. 13  schematically illustrates a diagram of a backplane according to an example of the fourth embodiment. In  FIG. 13 , a backplane  130  comprises a connector  131  for connecting the module (not shown) to the backplane  130 , a MCU  133  and a power source  134 . The module may be, for example, any one of the modules as shown in  FIGS. 1-4 . The connector  131  comprises an array of pins  132 . Pins  1321 - 1324  of the array  132  are selected such that connection of the module with the backplane  130  can be determined based on connection of the selected pins  1321 - 1324  with corresponding pins of the connector of the module. The pin  1321  is connected to the power source  134  via a resister  135  and to the MCU  133 , the pin  1322  is connected to the ground, and the pin  1323  is short-circuited with the pin  1324 . 
         [0079]    In a fifth embodiment of the backplane according to the present invention, one of the selected pins of the backplane is connected to the ground via a fourth resister and to the MCU, and another one of the selected pins is connected to a power source. 
         [0080]      FIG. 14  schematically illustrates a diagram of a backplane according to an example of the fifth embodiment. In  FIG. 14 , a backplane  140  comprises a connector  141  for connecting the module (not shown) to the backplane  140 , a MCU  143  and a power source  144 . The module may be, for example, any one of the modules as shown in  FIGS. 1-4 . The connector  141  comprises an array of pins  142 . Pins  1421 - 1424  of the array  142  are selected such that connection of the module with the backplane  140  can be determined based on connection of the selected pins  1421 - 1424  with corresponding pins of the connector of the module. The pin  1421  is connected to the ground via a resister  145  and to the MCU  143 , the pin  1422  is connected to the power source  144 , and the pin  1423  is short-circuited with the pin  1424 . 
         [0081]    In a third aspect of the present invention, there is provided a method for determining connection of a module with a backplane. Hereinafter, reference will be made to  FIG. 15  to describe the method according to the third aspect of the present invention. 
         [0082]    In the method for determining connection of the module with the backplane according to the present invention, the module comprises a first connector comprising an array of pins, and the backplane comprises a second connector comprising an array of pins corresponding to the array of pins of the first connector. It will be understood that the module can be implemented with any one of the modules as described with reference to  FIGS. 1-7 , and the backplane can be implemented with any one of the backplanes as described with reference to  FIGS. 8-14 . 
         [0083]    As shown in  FIG. 15 , a method for determining connection of a module with a backplane  1500  starts with a step  1510 . 
         [0084]    At the step  1510 , a portion of the pins of the first connector is selected. For example, there are selected at least three pins which are located at or in close proximity to a periphery of the first connector, as schematically shown in  FIG. 2 . Alternatively, there are selected at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the first connector, respectively, as schematically shown in  FIGS. 3 and 4 . 
         [0085]    Then, the first connector is connecting to the second connector (step  1520 ). 
         [0086]    Next, at a step  1530 , it is detected whether the selected pins of the first connector are effectively connected to the corresponding pins of the second connector. 
         [0087]    Then, it is determined whether the module is effectively connected to the backplane based on the detecting (step  1540 ). 
         [0088]    It should be noted that, in the present invention, the process of determining the connection of the module with the backplane based on the connection of the selected pins with the corresponding pins of the second connector goes with the following assumption. That is, once the selected pins of the first connector are effectively connected to the corresponding pins of the second connector, it could be considered that all the pins of the first connector are effectively connected to the corresponding pins of the second connector, thereby determining the module is effectively connected to the backplane. 
         [0089]    In an embodiment of the method according to the present invention, the method further comprises configuring the selected pins such that once the selected pins are effectively connected to the backplane, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the backplane is detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane is determined based on the signal. 
         [0090]    Hereinafter, reference will be made to  FIG. 16  to describe a specific example according to the embodiment of the method of the present invention. 
         [0091]    There is shown on the left of  FIG. 16  the module supporting hot plug  60  as illustrated in  FIG. 6 , and there is shown on the right of  FIG. 16  a backplane  160  to be used in conjunction with the module  60 . The backplane  160  comprises a second connector  161  for connecting the module  60  to the backplane  160 . The connector  161  comprises an array of pins  162 . Four pins  1621 - 1624  are located in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the array  162 , respectively, and correspond to the four pins  621 - 624  of the module  60 . 
         [0092]    In this example, the method further comprises connecting one of the four selected pins to a power source via a first resister and to a MCU, connecting another one of the four selected pins to the ground, and short-circuiting the remaining two of the four selected pins with each other. As shown on the left of  FIG. 16 , the four pins  621 - 624  of the module are selected. The pin  621  is connected to the power source  64  via a resister  65  and to the MCU  63 , the pin  622  is connected to the ground and the pin  623  is short-circuited with the pin  624 . 
         [0093]    Further, the method comprises short-circuiting the pin of the second connector corresponding to the one of the four selected pins with the pin of the second connector corresponding to one of the remaining two of the four selected pins, and short-circuiting the pin of the second connector corresponding to the another one of the four selected pins with the pin of the second connector corresponding to the other of the remaining two of the four selected pins. As shown on the right of  FIG. 16 , the pin  1621  is short-circuited with the pin  1624 , and the pin  1622  is short-circuited with the pin  1623 . 
         [0094]    In this example, detecting whether the four selected pins are effectively connected to the corresponding pins comprises detecting a voltage at the one of the four selected pins by the MCU, and determining whether the module is effectively connected to the backplane based on the detecting comprises determining the module is effectively connected to the backplane if the detected voltage is equal to zero, or determining the module is not effectively connected to the backplane if the detected voltage is equal to the voltage supplied by the power source. 
         [0095]    Come back to  FIG. 16 . After the module  60  is connected to the backplane  160 , a voltage at the pin  621  can be detected by the MCU  63 . 
         [0096]    On the one hand, if the selected pins  621 - 624  are effectively connected to the corresponding pins  1621 - 1624 , a current will flow from the power source  64  to the ground in the following direction: the pin  621 →the pin  1621 →the pin  1624 →the pin  624 →the pin  623 →the pin  1623 →the pin  1622 →the pin  622 →ground. Only when all of the four selected pins  621 - 624  are connected to the corresponding pins  1621 - 1624 , a circuit comprising the selected pins  621 - 624  and the corresponding pins  1621 - 1624  will be turned on, and a low level will be detected at the pin  621 . So, the MCU  63  can determine the module  60  is effectively connected to the backplane  160  based on the low level, and thus determine the module  60  should be enabled. Therefore, the module  60  will have output/input values. 
         [0097]    On the other hand, if any one of the four selected pins  621 - 624  is not effectively connected to the corresponding pin of the backplane  160 , the circuit comprising the four selected pins  621 - 624  and the corresponding pins  1621 - 1624  will be turned off, and a high level will be detected at the pin  621 . Thus, the MCU  63  can determine the module  60  is not effectively connected to the backplane  160  based on the high level, and thus determine the module  60  should not be enabled. Therefore, the module  60  will not have output/input values. 
         [0098]    It should be understood that hereinbefore is described a specific example of the method for determining connection of a module with a backplane by way of example as shown in  FIG. 16  and the present invention is not limited thereto. For example, although it is shown in  FIG. 16  that the pin  621  of the four selected  621 - 624  is connected to the MCU  63  and a lower level can be detected at the pin  621  with the MCU  63  when the four selected  621 - 624  are effectively connected to the corresponding pins  1621 - 1625 , it is possible that any one of the selected pins  623 - 624  can be connected to the MCU  63  and the lower level can be detected at any one of the selected pins  623 - 624  with the MCU  63  when the four selected  621 - 624  are effectively connected. 
         [0099]    In another specific example according to the embodiment of the method of the present invention, the method further comprises: connecting one of the four selected pins to a power source via a first resister and to a MCU, connecting another one of the four selected pins to the ground, short-circuiting the remaining two of the four selected pins with each other, short-circuiting the pin of the second connector corresponding to the one of the four selected pins with the pin of the second connector corresponding to one of the remaining two of the four selected pins, and short-circuiting the pin of the second connector corresponding to the another one of the four selected pins with the pin of the second connector corresponding to the other of the remaining two of the four selected pins; wherein detecting whether the four selected pins are effectively connected to the corresponding pins comprises detecting a voltage at the one of the four selected pins with the MCU; and wherein determining whether the module is effectively connected to the backplane based on the detecting comprises determining the module is effectively connected to the backplane if the detected voltage is equal to zero, or determining the module is not effectively connected to the backplane if the detected voltage is equal to the voltage supplied by the power source. This specific example according to the embodiment of the method of the present invention may be implemented, for example, with the module  70  as shown in  FIG. 7  and the corresponding backplane (not shown). Since this example is similar to the example as described with reference to  FIG. 16 , the detailed description thereof is omitted herein. 
         [0100]    According to a fourth aspect of embodiments of the present invention, there is provided a system comprising a module supporting hot plug and a backplane. The module comprises a first connector comprising a first array of pins, and the backplane comprises a second connector comprising a second array of pins corresponding to the first array of pins. A portion of the pins of the first array are selected such that connection of the module with the backplane can be determined based on connection of the selected pins of the first array with corresponding pins of the second array. 
         [0101]    According to an exemplary embodiment, the selected pins of the first array and the corresponding pins of the second array can be configured such that once the selected pins of the first array are effectively connected to the corresponding pins of the second array, the selected pins will come to be connected in series with each other, and a signal for indicating an effective connection of the selected pins with the corresponding pins of the second array can be detected at one terminal of the serial connection of the selected pins, whereby an effective connection of the module with the backplane can be determined based on the signal. More specifically, as an example only, one pin among the selected pins of the first array is connected a MCU while another one pin among the selected pins of the first array is grounded, and part of the remaining pins of the selected pins of the first array are short-circuited with each other. Meanwhile, part of the corresponding pins of the second array are short-circuited with each other in a way complementary with the short-circuited pins of the first array, so as to form a closed circuit when the selected pins of the first array are effectively connected to the corresponding pins of the second array. For example, the selected pins of the first array may comprise a first pair of pins and a second pair of pins and the corresponding pins of the second array may comprise a third pair of pins and a fourth pair of pins corresponding to the first pair of pins and the second pair of pins respectively. One of the second pair of pins is connected to a MCU while the other one of the second pair of pins is grounded, one of the first pair of pins is short-circuited with the other of the first pair of pins, and one of the third pair of pins is short-circuited with one of the fourth pair of pins and the other one of the third pair of pins is short-circuited with the other one of the fourth pair of pins. 
         [0102]    According to an exemplary embodiment, the selected pins can comprise at least three pins which are located at or in close proximity to a periphery of the first array. 
         [0103]    According to an exemplary embodiment, the selected pins can comprise at least four pins which are located at or in close proximity to an upper left corner, a lower left corner, a lower right corner and an upper right corner of the first array, respectively. 
         [0104]    According to an exemplary embodiment, the selected pins can further comprise at least one pin which is located between the pins which are located at or in close proximity to the upper left and lower left corners of the first array, or between the pins which are located at or in close proximity to the lower right and upper right corners of the first array. 
         [0105]    According to an exemplary embodiment, the system can further comprise a Micro Controller Unit (MCU) connected to the first connector and configured to determine, based on the determined connection of the module with the backplane, whether the module should be enabled. In this embodiment, one of the selected pins is connected to a power source via a first resister and to the MCU, and another one of the selected pins is connected to the ground. Alternatively, one of the selected pins is connected to the ground via a second resister and to the MCU, and another one of the selected pins is connected to a power source. 
         [0106]    According to an exemplary embodiment, the system can further comprise a Micro Controller Unit (MCU) connected to the second connector. In this embodiment, one of the pins of the second array corresponding to the selected pins of the first array is connected to a power source via a third resister and to the MCU, and another one of the pins of the second array corresponding to the selected pins of the first array is connected to the ground. Alternatively, one of the pins of the second array corresponding to the selected pins of the first array is connected to the ground via a fourth resister and to the MCU, and another one of the pins of the second array corresponding to the selected pins of the first array is connected to a power source. 
         [0107]    Finally, it should also be appreciated that the above description provides examples to describe the invention and to enable a person of ordinary skill in the art to make and use the invention. However, this above description is not intended to limit the invention to the precise terms set forth. Thus, while the invention has been described in detail with reference to the examples set forth above, those of ordinary skill in the art may made alterations, modifications and variations to the examples without departing from the scope of the invention.