Patent Publication Number: US-2012047296-A1

Title: Control module for communicaion networks and method for using the same

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to control modules for communication networks, and particularly to a control module capable of switching a communication network to be selectively controlled by different control units. 
     2. Description of Related Art 
     A server of a communication network (e.g., the Internet or intranets) generally includes a master control unit and at least one slave control unit. In use, the master control unit is first used to control the communication network. When the master control unit malfunctions, the communication network is switched to be controlled by the slave control unit, until the master control unit is repaired, then the communication network is switched to be controlled by the master control unit again. However, most conventional switch devices for switching communication networks to be selectively controlled by their master control units and slave control units have complicated hardware structures and are costly. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present control module can be better understood with reference to the following drawings. The components in the various drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present control module. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the figures. 
         FIG. 1  is a block diagram of a control module for communication networks, according to a first exemplary embodiment. 
         FIG. 2  is a flow chart of a method for switching a communication network to be selectively controlled by different control units, according to an exemplary embodiment. 
         FIG. 3  is a block diagram of a control module for communication networks, according to a second exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a control module  100 , according to a first exemplary embodiment. The control module  100  can be used in a server (not shown) of a communication network  200  such as the Internet or an intranet, to control the communication network  200 . The control module  100  includes a master control unit  11 , a slave control unit  12 , and a switch unit  13 . 
     The master control unit  11  includes a pulse signal generator  111 , a control signal generator  113 , and an interface  115 . The pulse signal generator  111  and the control signal generator  113  are both electrically connected to the interface  115 . The pulse signal generator  111  can generate a master pulse signal, and the control signal generator  113  can generate a master control signal. Similar to the master control unit  11 , the slave control unit  12  includes a pulse signal generator  121 , a control signal generator  123 , and an interface  125 . The pulse signal generator  121  and the control signal generator  123  are both electrically connected to the interface  125 . The pulse signal generator  131  can generate a slave pulse signal, and the control signal generator  123  can generate a slave control signal. 
     The interface  115  and the interface  125  are electrically connected to each other. In use, the master pulse signal is transmitted to the slave control unit  12  through the interfaces  115 ,  125 , and the slave pulse signal is transmitted to the master control unit  11  through the interfaces  125 ,  115 . Upon receiving each other&#39;s pulse signals, the master control unit  11  and the slave control unit  12  can cooperatively regulate phases of the master pulse signal and the slave pulse signal to be synchronous. However, in the first exemplary embodiment, only the master pulse signal is used. 
     The switch unit  13  includes a timer  14  and a multiplexer  15 . The timer  14  is electrically connected to the interface  115  and the multiplexer  15 . The master pulse signal is transmitted to the timer  14  via the interface  115  to periodically reset the timer  14 . Therefore, the master pulse signal prevents the timer  14  from timing for an interval that exceeds a period of the master pulse signal. The timer  14  can generate selecting signals having different voltage levels changing according to the timing status of the timer  14 . Particularly, if timing intervals of the timer  14  are shorter than or equal to the period of the master pulse signal, the timer  14  generates a first selecting signal, for example, a signal with a relatively higher voltage level. If a timing interval of the timer  14  exceeds the period of the master pulse signal, the timer  14  generates a second selecting signal, for example, a signal with a relatively lower voltage level. The multiplexer  15  receives the selecting signals from the timer  14 . 
     The interfaces  115 ,  125  are both electrically connected to the multiplexer  15 . The master control unit  11  and the slave control unit  12  respectively transmit the master control signal and the slave control signal to the multiplexer  15  through the interfaces  115 ,  125 . The multiplexer  15  is electrically connected to the communication network  200 , and selectively transmits one of the master control signal and the slave control signal to the communication network  200  to place the communication network  200  under control of either the master control unit  11  or the slave unit  12  accordingly. Particularly, the multiplexer  15  transmits the master control signal to the communication network  200  when receiving the first selecting signal, and transmits the slave control signal to the communication network  200  when receiving the second selecting signal. 
     Referring to  FIG. 2 , a method of using the control module  100  to control the communication network  200 , according to an exemplary embodiment, is provided. The method includes the following operations 
     The timer  14  starts to time (S 1 ). The control signal generators  113 ,  123  respectively generate the master control signal and the slave control signal and transmit the master control signal and the slave control signal to the multiplexer  15  (S 2 ). At the same time, the switch unit  13  detects if the master pulse signal is generated (S 3 ). If the master control unit  11  works normally, the pulse signal generator  113  generates the master pulse signal and transmits the master pulse signal to the timer  14  to periodically reset the timer  14 . Upon receiving the master pulse signal, the timer  14  generates the first selecting signal and transmits the first selecting signal to the multiplexer  15  (S 4 ). Upon receiving the first selecting signal, the multiplexer  15  transmits the master control signal to the communication network  200  (S 5 ). Thus, the communication network  200  is controlled by the master control unit  11 . 
     If the master control unit  11  malfunctions, it is not able to generate the master pulse signal. Without receiving the master pulse signal, the timer  14  is not periodically reset and an interval from the last reset exceeds the period of the master pulse signal, i.e., overtime (S 6 ). Thus, the timer  14  generates the second selecting signal and transmits the second selecting signal to the multiplexer  15  (S 7 ). Upon receiving the second selecting signal, the multiplexer  15  transmits the slave control signal to the communication network  200  (S 8 ). Thus, the communication network  200  is controlled by the slave control unit  12 . In this way, master control unit  11  malfunctions will not interfere with functioning of the communication network  200 . When the master control unit  11  is repaired, the master pulse signal transmitted to the timer  14  resumes. Thus, the timer  14  resumes to generate the first selecting signal transmitted to the multiplexer  15 . Upon receiving the first selecting signal, the multiplexer  15  resumes transmitting the master control signal to the communication network  200 , returning control of the communication network  200  to the master control unit  11  again. 
     Referring to  FIG. 3 , a control module  300 , according to a second exemplary embodiment, is provided. The control module  300  is similar to the control module  100 , except that the control module  300  includes a plurality of slave control units  12 . The interface  115  of the master control unit  11  and the interfaces  125  of all the slave control units  12  are electrically connected to each other, such that the master control unit  11  and all the slave control units  12  can respectively receive the master/slave pulse signals of each other. Upon receiving pulse signals generated by each other, the master control unit  11  and the slave control units  12  cooperatively regulate phases of the master pulse signal and the slave pulse signals to be synchronous. 
     The interface  115  and all the interfaces  125  are also electrically connected to the timer  14  and the multiplexer  15 , such that all the pulse signals generated by the master control unit  11  and the slave control units  12  are transmitted to the timer  14 , and all the control signals generated by the master control unit  11  and the slave control units  12  are transmitted to the multiplexer  15 . When the master pulse signal stops, the switch unit  13  can select one of all the slave pulse signals to periodically reset the timer  14 , and the timer  14  then generates a selecting signal corresponding to the selected slave pulse signal and transmits the selecting signal to the multiplexer  15 . Upon receiving the selecting signal, the multiplexer  15  transmits the slave control signal generated by a slave control unit  12  that generates the selected slave pulse signal to the communication network  200  to control the communication network  200 . 
     Similar to use of the control module  100 , in use of the control module  300 , when receiving the master pulse signal, the switch unit  13  first transmits the master control signal to the communication network  200  to control the communication network  200 . When the master control unit  12  malfunctions and stops generating the master pulse signal, the switch unit  13  selects a slave control unit  12  to control the communication network  200 . Particularly, the switch unit  13  transmits the slave pulse signal generated by the selected slave control unit  12  to the timer  14  to periodically reset the timer  14 , and the timer  14  generates a selecting signal corresponding to the selected control unit  12  and transmits the selecting signal to the multiplexer  15 . Upon receiving the selecting signal, the multiplexer  15  transmits the slave control signal generated by the selected slave control unit  12  to the communication network  200  to control the communication network  200 , thereby maintaining the communication network  200  to function normally. If the selected slave control unit  12  also malfunctions, the switch unit  13  can detect that the selected control unit  12  stops generating the slave pulse signal, and then select one of other slave control units  12  to control the communication network  200  as above detailed method. 
     The present control module  100  can automatically switch the communication network  200  to be selectively controlled by the master control unit  11  and the at least one slave control unit  12 , thereby maintaining the communication network  200  to function normally when the master control unit  11  malfunctions. Compared with conventional switch devices for switching communication networks to be selectively controlled by different control units, the control module  100  has a simpler hardware structure and conserves cost. 
     It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of structures and functions of various embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.