Abstract:
A backup control system comprises a control package, a file package including a battery monitor and a flip-flop circuit, and a back board having a return wire which provides connection/disconnection of the monitor terminal of the monitor. The monitor checks a voltage of the monitor terminal at all times and outputs a reset signal to the flip-flop circuit when the voltage of the monitor terminal becomes lower than a reference voltage. The return wire connects the monitor terminal to the power line when the file package is connected to the connection board, and disconnects the monitor terminal from the power line when the file package is removed from the connection board. The flip-flop circuit stores one of a set state and a reset state, and changes in state from the set state to the reset state when the reset signal is received from the monitor.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a system for backing up setting data of a plurality of circuit packages and, more specifically, to a backup method and system in a control system having a detachable backup memory. 
     2. Description of the Related Art 
     In general, a transmission apparatus in a switching system has a number of circuit packages (built-in circuit boards) which are detachably mounted on the backboard of the apparatus frame. This type of transmission apparatus further has a file package including a backup memory which stores start-up setting data such as a line connections state and a soft strap setting state of the transmission apparatus. When a communication service of the switching system is stopped due to, for instance, power shutoff, the communication service can be restored in a short time by using the start-up setting data stored in the backup memory. 
     FIG. 1 is a schematic block diagram showing a conventional control system having such a file package. A control package  10 , a host supervisory/controlling apparatus (i.e., a central control apparatus)  20 , a plurality of circuit packages  30  to be set, and a file package  40  are connected to each other via a backboard. Each of the circuit packages  10 ,  30  and  40  are detachably mounted by means of a connector. The control package  10  includes a processor  11  for controlling the circuit packages  30 , an parallel I/O interface  12  for data communication with external systems, and interfaces for data communication with the host supervisory/controlling apparatus  20  and the packages  30  to be set. The file package  40  includes a backup memory  41  for storing start-up setting data, a battery  42  for supplying power to the backup memory  41 , and a mode setting switch  43  that indicates whether there has occurred replacement work on the file package  40 . 
     In the transmission apparatus having the above configuration, an operation of replacing a faulty circuit package with a new one or the same circuit package in another transmission apparatus is performed manually. In such an operation, there occurs no problem in replacing the control package  10  or the package  30  to be set. However, since the file package  40  stores data to be set in the associated transmission apparatus, a file package that has already been used in another transmission apparatus cannot be used for replacement as it is. 
     Therefore, a certain availability checking means is needed which allows the processor  11  of the control package  10  to recognize whether the start-up setting data stored in the file package  40  is available. In the above conventional apparatus, the mode setting switch  43  is provided as an availability checking means and a switching operation therefor is performed manually. More specifically, in restarting the apparatus, the processor  11  of the control package  10  checks the state of the mode setting switch  43 . If the mode setting switch  43  is on, the processor  11  judges that the file package  40  is a substituted one. Thus, the processor  11  initializes the backup memory  41 , starts up the apparatus, and stores start-up setting data of the respective packages into the backup memory  41 . Upon completion of the restart of the apparatus, an operator switches the mode setting switch  43  to the off state. On the other hand, if the mode setting switch  43  is off in restarting the apparatus, the processor  11  judges that the file package  40  is not a substituted one. Thus, the processor  11  reads the start-up setting data from the backup memory  41 , and restarts the apparatus. 
     A description will be made of another general availability checking means. First, in mounting the control package  10  and the file package  40 , a particular pattern that was determined when the transmission apparatus was designed is stored into the backup memory  41 . When the apparatus is restored from a power shutoff state, the processor  11  reads a pattern from the backup memory  41 , and judges availability of the data stored in the backup memory  41  based on whether the readout pattern is the preset particular pattern. 
     However, in the conventional system in which the mode setting switch  43  is operated manually, it cannot be checked whether the start-up setting data stored in the backup memory  41  is available. Further, an operator is required to be present until completion of restarting. Since there are many packages to be set, it is very difficult to improve the working efficiency. Further, it is virtually impossible to be free of careless mistakes. 
     While the availability checking method using the particular pattern can check whether the file package  40  is the same one, it cannot check the start-up setting data of the backup memory  41  is available. This is so because even if the file package  40  is the same, a possibility is not denied that during power shutoff the file package  40  was used in another transmission apparatus and the data was written. 
     As described above, in the conventional system, it cannot be checked whether the start-up setting data stored in the backup memory was changed while the system was stopped. Therefore, for instance, when the power is shut off for maintenance and inspection, or the like, it is not completely assured that the same start-up setting data is stored. In particular, if a transmission apparatus in a switching system is restarted with start-up setting data of another transmission apparatus, a wrong connection state is established in the transmission apparatus concerned, causing too large influences on society. Therefore, there exists a problem that the apparatus cannot be restarted automatically when it is restored from a power shutoff state, for instance. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a control system which can positively judge whether data stored in a backup memory is the same as the previous data, when the apparatus is restarted. 
     Another object of the invention is to provide a method and system which can automatically restart an apparatus having a backup memory. 
     A further object of the invention is to provide a circuit package including a backup memory in which, when the apparatus is restarted, a control package can positively judge whether data stored in the backup memory is the same as the previous data. 
     A backup memory package according to the present invention is detachably connected to a control system by means of a connection board. The control system is comprised a plurality of circuit packages detachably connected to the connection board, each circuit package requiring start-up setting data for start-up operation. The backup memory package is comprised of a battery for supplying power to the backup memory package through a power line and a backup memory for storing the start-up setting data. 
     The backup memory package is further provided with a battery monitor, a connection/disconnection member, and a flag memory. The monitor checks a voltage of a monitor input terminal at all times and generates a reset signal when the voltage of the monitor input terminal becomes lower than a predetermined reference voltage. The connection/disconnection member connects the monitor input terminal to the power line when the backup memory package is connected to the connection board, and disconnects the monitor input terminal from the power line when the backup memory package is removed from the connection board. The flag memory stores one of a set state and a reset state, and changes in state from the set state to the reset state when the reset signal is received from the monitor. 
     The control package controls the circuit packages and the backup memory package through the connection board, and determines whether the start-up setting data stored in the backup memory is valid or not, by checking the flag state of the flag memory, set or reset. 
     More specifically, the connection/disconnection member comprises a first connector and a second connector. The first connector is provided in the backup memory package, having a plurality of conductors for electrically connecting the backup memory package to the connection board. Two conductors thereof are connected to the power line and the monitor input terminal, respectively. The second connector is provided in the connection board detachably connected to the first connector. The second connector has a plurality of conductors corresponding to those of the first connector, two conductors thereof corresponding to the two conductors of the first connector are connected to each other, forming a return wire. 
     The monitor monitors a voltage of the battery through the power line and the connection/disconnection member when the backup memory package is connected to the connection board. The monitor outputs the reset signal to the flag memory when the backup memory package is removed from the connection board or when a voltage of the battery becomes lower than the predetermined reference voltage. The predetermined reference voltage is preferably set higher than a minimum voltage that assures holding of data stored in the backup memory and the flag memory. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram showing an example of a conventional control system; 
     FIG. 2 is a block diagram showing a control system according to an embodiment of the present invention; 
     FIG. 3 is a block diagram showing a more detailed configuration of a file package in the embodiment; 
     FIG. 4 is a flowchart showing a start-up control flow performed in the embodiment when the file package is mounted; 
     FIG. 5 is a flowchart showing a restart control flow performed in the embodiment when the file package is available; and 
     FIG. 6 is a flowchart showing a restart control flow performed in the embodiment when the file package is not available. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 2, a file package  101  is detachably connected to a backboard  201  via a connector  202 , and a control package  301  is detachably connected to the backboard  201  via connectors  203  and  204 . A plurality of circuit packages  401  to be set are detachably connected to the backboard  201  via respective connectors  205 , which are connected to the connector  204  via the backboard  201 . The control package  301  is connected to a host supervisory/controlling apparatus  501 . 
     The file package  101  has a backup memory  102  which stores start-up setting data that are necessary to start up the packages  401  to be set. A data bus, an address bus, and a control bus of the backup memory  102  are connected to the connector  202  via a bus buffer  103 . A backup battery  104  supplies power to the backup memory  102 , a power monitoring circuit  105  and a flip-flop circuit  106  via a power line  107 . The power line  107  is also connected to the connector  202 , and is returned to the file package  101  via a return wire  206  (located in the backboard  201 ) and connected to a monitoring terminal SV of the power monitoring circuit  105 . Therefore, if the file package  101  is pulled off from the backboard  201 , the power line  107  and the power monitoring terminal SV of the power monitoring circuit  105  are necessarily disconnected electrically from each other. 
     The power monitoring circuit  105  always monitors a voltage Vcc of the battery  104  via the power line  107  and the return wire  206 . If the power supply voltage Vcc becomes lower than a predetermined voltage, the power monitoring circuit  105  supplies a reset signal to the flip-flop circuit  106 . This signal may be thought of as a disconnection signal. Since the power monitoring circuit  105  monitors the power supply voltage Vcc via the power line  107  and the return wire  206 , the voltage applied to the monitoring terminal SV quickly decreases from Vcc when the file package  101  is pulled off from the backboard  201 . Therefore, the power monitoring circuit  105  can detect not only voltage reduction of the battery  104  but also pulling off of the file package  101  from the backboard  201 . Thus, monitor  105  and connector  202  may be thought of as cooperating to form a disconnection detector. 
     The reset terminal (R) of the flip-flop circuit  106  is connected to the power monitoring circuit  105 , and its set terminal (S) and output terminal (Q) are connected to the connector  202 . A grounding line  108  is connected to the connector  202  and grounded in the backboard  201 . 
     The control package  301  has a processor  302  for controlling the packages  401  to be set. A data bus, an address bus, and a control bus of the processor  302  are connected to the connector  203  via a bus buffer  303 . The bus buffer  303  of the control package  301  and the bus buffer  103  of the file package  101  are connected to each other via the backboard  201  and the connectors  202  and  203 , whereby the processor  302  and the backup memory  102  are connected to each other via the buses. 
     A parallel input/output (PIO) circuit  304  is connected to the processor  302  via the bus. A one-bit output terminal of the PIO circuit  304  is connected to the set terminal (S) of the flip-flop circuit  106  of the file package  101  via the connectors  202  and  203 . On the other hand, the output terminal (Q)of the flip-flop circuit  106  is connected to a one-bit input terminal of the PIO circuit  304  via the connectors  202  and  203 . Therefore, the processor  302  can set the flip-flop circuit  106  of the file package  101  through the PIO circuit  304 , and can also check its output state. 
     Through an interface circuit  305  of the apparatus, the processor  302  can transmit the start-up setting data to the packages  401  to be set, and perform supervision and control of their setting states. Further, the processor  302  communicates with a host supervisory/controlling apparatus  501  through a communication circuit  306 . 
     As shown in a detailed manner in FIG. 3, the file package  101  has a connector  202 A for connection to the backboard  201 , and the return wire is not provided in the connector  202 A. Therefore, in a state that the file package  101  is removed from the backboard  201 , the power line  107  of the file package  101  and the monitoring terminal SV of the power monitoring circuit  105  are disconnected from each other. The bus buffer  103 , which is comprised of uni-directional address bus buffer BB A  and control bus buffer BB C  and a bi-directional data bus buffer BB D , connects pins of the connector  202 A and input/output terminals of the backup memory  102 . 
     The power monitoring circuit  105  is comprised of a voltage comparator  109 , a reference voltage generator  110 , and a reset controller  111 . The voltage comparator  109  compares a voltage V P  that is applied to the monitoring terminal SV with a reference voltage V ref . If the monitoring voltage V P  becomes lower than the reference voltage V ref , the comparator  109  supplies a low-level voltage to the reset controller  111 . The reference voltage V ref  is set higher than a minimum voltage that assures holding of data stored in the backup memory  102  and the flip-flop circuit  106 . 
     Upon receiving the low-level voltage from the comparator  109 , the reset controller  111  supplies a reset signal to the reset terminal (R) of the flip-flop circuit  106 , to reset it. As described above, when the file package  101  is removed from the backboard  201  or the voltage Vcc of the battery  104  decreases, the voltage comparator  109  supplies the low-level voltage to the reset controller  106 . 
     Start-Up Operation 
     When the file package  101  and the packages  401  to be set are mounted on the backboard  201 , the processor  302  of the control package  301  first execute a start-up process of the packages  401  to be set. 
     As shown in FIG. 4, the processor  302  initializes the backup memory  102  of the file package  101  and performs a memory check (S 601 ). If abnormality is found in the memory check (No in S 602 ), which means a failure of the file package  101 , the processor  302  announces warning and turns on an abnormality lamp for the package  101  (S 603 ). Recognizing the warning, an operator replaces the faulty file package  101  with a new one. 
     If the backup memory  102  is normal (Yes in S 602 ), the processor  302  selects one subject package, and detects its setting state (S 604 ). If start-up setting of the selected subject package has already been completed (Yes in S 605 ), the processor  302  reads start-up setting data from the selected subject package and stores it into the backup memory  102  (S 606 ). If the selected subject package has not been subjected to start-up setting (No in S 605 ), the processor  302  sets the default start-up setting data in the selected subject package and, at the same time, stores that start-up setting data into the backup memory  102  (S 607 ). Steps S 604 -S 607  are repeated until all the packages  401  have been subjected to start-up setting (S 608 ). 
     If all the packages have been subjected to start-up setting (Yes in S 608 ), the processor  302  sets the flip-flop circuit  106  through the PIO circuit  304  (S 609 ), to complete the start-up of the transmission apparatus. 
     Restart Operation 
     When the transmission apparatus that has been subjected to the start-up setting in the above manner is recovered from a power shutoff state due to, for instance, maintenance and inspection, the processor  302  restarts the apparatus according to the following steps. 
     As shown in FIG. 5, when the power is restored, the processor  302  first checks the state of the output terminal Q of the flip-flop circuit  106  of the file package  101  through the PIO  304  (S 701 ). The set state of the flip-flop circuit  106  (Yes in S 701 ) indicates that the file package  101  has never been pulled off from the backboard  201  nor the voltage of the battery  104  has decreased during the power shutoff. Therefore, the processor  302  can reset the transmission apparatus concerned using the start-up setting data stored in the backup memory  102 . 
     The processor  302  selects one subject package, and detects its setting state (S 702 ). If start-up setting of the selected subject package has already been completed (Yes in S 703 ), it is checked whether all the packages  401  have been subjected to start-up setting (S 705 ). If the selected subject package has not been subjected to start-up setting (No in S 703 ), the processor  302  reads start-up data for the package concerned from the backup memory  102  of the file package  101 , and installs it in the package concerned through the interface  305  (S 704 ). Steps S 702 -S 704  are repeated until all the packages  401  are subjected to start-up setting (S 705 ). When all the packages  401  have been subjected to start-up setting (Yes in S 705 ), the processor  302  restarts the transmission apparatus. 
     On the other hand, the reset state of the flip-flop circuit  106  (No in S 701 ) indicates that, during power shutoff, the file package  101  has been replaced, it has been pulled off from the backboard  201 , or the voltage of the battery  104  has decreased to a value smaller than the minimum voltage necessary to hold data of the memory. Therefore, the processor  302  cannot reset the transmission apparatus concerned using the start-up setting data stored in the backup memory  102 . 
     In this case, as shown in FIG. 6, the processor  302  executes a restart process by a start-up operation that is performed in mounting the file package  101  as shown in FIG.  4 . More specifically, as shown in FIG. 6, the processor  302  initializes the backup memory  102  of the file package  101  and performs a memory check (S 801 ). If abnormality is found in the memory check (No in S 802 ), which means a failure of the file package  101 , the processor  302  announces warning and turns on an abnormality lamp for the package  101  (S 803 ). Recognizing the warning, an operator replaces the faulty file package  101  with a new one. 
     If the backup memory  102  is normal (Yes in S 802 ), the processor  302  selects one subject package, and detects its setting state (S 804 ). If start-up setting of the selected subject package has already been completed (Yes in S 805 ), the processor  302  reads start-up setting data from the selected subject package and stores it into the backup memory  102  (S 806 ). If the selected subject package has not been subjected to start-up setting (No in S 805 ), the processor  302  sets the default start-up setting data in the selected subject package and, at the same time, stores that start-up setting data into the backup memory  102  (S 807 ). Steps S 604 -S 607  are repeated until all the packages  401  have been subjected to start-up setting (S 808 ). 
     If all the packages have been subjected to start-up setting (Yes in S 808 ), the processor  302  sets the flip-flop circuit  106  through the PIO circuit  304  (S 809 ), to complete the start-up of the transmission apparatus. 
     According to the present invention, by checking the state of the flip-flop circuit of the file package, the control package can judge whether the file package has been removed. At the occurrence of file package replacement, the start-up data of the backup memory of the file package is judged to be not available. The power monitoring circuit of the file package always monitors the battery. When the battery voltage decreases, the power monitoring circuit resets the flip-flop circuit. Thus, at the occurrence of battery voltage reduction, the start-up setting data of the backup memory is judged to be not available. 
     Therefore, the control system according to the present invention can positively judge availability of the data stored in the backup memory of the file package that is connected to the control package and, for example, can automatically execute in a positive manner the operation of restarting the apparatus in restoring it from a power shutoff state.