JP2008109325A - Communications system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system capable of rapidly checking the setting and connection of a communication module without complicating the system. <P>SOLUTION: A transmission means 22 transmits a function (a master module/a slave module) of a communication module 2 recognized on the basis of the setting of an internal switch 21 to the communication module 3 through a relay bus 1. A collating means 23 collates the function (the master module/the slave module) transmitted from the communication module 3 and the function of the communication module 2 recognized by itself. A stop means 24 stops the data output from the communication module 2 according to the result in the collating means 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication system configured by connecting a plurality of communication modules to each other via a bus.

  In a field control system of a plant or the like, process control is performed by performing communication between a monitoring terminal and a field device or between field devices. In the case where optical communication or other relay buses are provided in the communication path for convenience of communication distance, communication modules are connected to both ends of the relay bus.

  FIG. 3 shows an example in which the communication module 102 and the communication module 103 are provided at both ends of the relay bus 101. A bus 104 is connected to the upstream or upper communication module 102, and a bus 105 is connected to the downstream or lower communication module 103.

  The communication module 102 and the communication module 103 are configured as a common communication module, and their functions are switched by an internal switch. In this example, a normal communication state can be ensured by setting the upstream side or the upper side as the master module and the downstream side or the lower side as the slave modules. That is, as shown in FIG. 3, the internal switch 102a of the communication module 102 is set on the master side, and the internal switch 103a of the communication module 103 is set on the slave side.

  FIG. 4 is a timing chart showing communication timing. The communication module 102 functioning as a master module receives data (data A and data B) from the bus 104 and outputs the data to the relay bus 101 in synchronization with the operation clock of the communication module 102. The communication module 103 functioning as a slave module receives data from the relay bus 101 and outputs the data to the bus 105 in synchronization with the operation clock of the communication module 103. Similarly, data transfer in the reverse direction from the bus 105 to the bus 104 is also possible.

JP 11-239197 A

  However, if there is an error in the setting of the internal switch of the communication module 102 or the communication module 103, the received data has no identification factor for identifying the communication module of the other party, so that the communication module 102 or the communication module 103 malfunctions. , Erroneous data is output to the bus 104 or the bus 105. If incorrect data output continues, there is a risk of adverse effects on the system.

  In order to prevent such a malfunction, it may be possible to check data using a CRC (Cyclic Redundancy Check), but it is necessary to buffer all the data in the CRC, which increases the circuit scale. This is not preferable because a large delay in data transfer occurs.

  An object of the present invention is to provide a communication system capable of quickly checking a setting state and a connection state of a communication module without complicating the system.

The communication system of the present invention is a communication system configured by connecting a first communication module and a second communication module via a relay bus, and the first communication module recognizes the function of the first communication module. First recognizing means that transmits the function recognized by the first recognizing means to the second communication module via the relay bus, and the second communication module. A second recognizing unit for recognizing the function of the second communication module, a collating unit for collating the function transmitted by the transmitting unit, and the function recognized by the second recognizing unit; It is characterized by comprising.
According to this communication system, since the function transmitted by the transmission unit and the function recognized by the second recognition unit are collated, the setting state and connection state of the communication module can be quickly determined without complicating the system. Can be checked.

  The first communication module and the second communication module are configured as a common communication module, and the common communication module functions as the first recognition unit and the second recognition unit, and the common communication module Switching means for switching the function of the communication module between the function as the first communication module and the function as the second communication module may be provided.

  A first bus for communication with an external module is connected to the first communication module, and a second bus for communication with an external module is connected to the second communication module, respectively. The communication frequency of the relay bus may be higher than the communication frequency of the first bus and the communication frequency of the second bus.

  The communication frequency of the relay bus may be an integer multiple of the communication frequency of the first bus and the second bus.

  The number of bits of the relay bus may be larger than the number of bits of the first bus and the second bus.

  You may provide the stop means which stops the output of the data from a said 2nd communication module according to the collation result in the said collation means.

  The function of the first communication module and the function of the second communication module may be functions as a master module or a slave module, respectively.

  According to the communication system of the present invention, since the function transmitted by the transmission unit and the function recognized by the second recognition unit are collated, the setting state and connection state of the communication module can be achieved without complicating the system. Can be checked quickly.

  Hereinafter, an embodiment of a communication system according to the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram illustrating a configuration of a communication system according to the present embodiment.

  As shown in FIG. 1, the communication system of the present embodiment is configured by connecting a communication module 2 and a communication module 3 to both ends of a relay bus 1. The upstream or upper communication module 2 is connected to an external communication module (not shown) via the bus 4. The downstream or lower communication module 3 is connected to an external communication module (not shown) via the bus 5.

  A common module is used for the communication module 2 and the communication module 3, and functions are set by an internal switch as a switching unit and a recognition unit. That is, by setting the internal switch 21 of the communication module 2 on the master side and the internal switch 31 of the communication module 3 on the slave side, the communication module 2 is set as a master module (upstream or upper module) for communication. Module 3 is used as a slave module (downstream or lower module).

  As shown in FIG. 1, the communication module 2 transmits the function (master module / slave module) of the communication module 2 recognized based on the setting state of the internal switch 21 to the communication module 3 via the relay bus 1. Transmission means 22, collation means 23 for collating the function (master module / slave module) transmitted from communication module 3 with the function of communication module 2 recognized by itself, and communication module according to the collation result in collation means 23 And stop means 24 for stopping the output of data from 2.

  Further, the communication module 3 includes a transmission unit 32 that transmits the function (master module / slave module) of the communication module 3 recognized based on the setting state of the internal switch 31 to the communication module 2 via the relay bus 1; A collation means 33 for collating the function (master module / slave module) transmitted from the communication module 2 with the function (master module / slave module) of the communication module 3 recognized by itself, and according to the collation result in the collation means 33 And stop means 34 for stopping the output of data from the communication module 3.

  The bus 4, the bus 5 and the relay bus 1 are all 5 bits, but the communication frequency is not the same, and the bus 4 and the bus 5 are 32 MHz, whereas the relay bus 1 is 64 MHz.

  The data transferred from the bus 4 to the communication module 2 is output to the relay bus 1 in synchronization with the operation clock of the communication module 2. Further, the data received by the communication module 3 is output to the bus 5 in synchronization with the operation clock of the communication module 3.

  The data transferred from the bus 5 to the communication module 3 is output to the relay bus 1 in synchronization with the operation clock of the communication module 3. Further, the data received by the communication module 2 is output to the bus 4 in synchronization with the operation clock of the communication module 2.

  FIG. 2 is a timing chart showing data communication timing via the relay bus 1.

  In the example of FIG. 2A, data transfer from the bus 4 to the bus 5 is shown. “Data A” and “Data B” transferred through the bus 4 are relayed from the communication module 2 with a certain delay time. Output to bus 1.

  The transmission means 22 of the communication module 2 outputs identification data 11 for identifying the function (master module / slave module) of the communication module 2 set by the internal switch 21 to the relay bus 1. For example, when the internal switch 21 is in the state shown in FIG. 1, the identification data 11 indicating the function as the master module is output. Since the communication frequency of the relay bus 1 is 64 MHz, as shown in FIG. 2A, “data A” and “data B” transferred through the bus 4 at 32 MHz are compressed to ½ time length. Thus, the identification data 11 can be inserted into the transfer data.

  The identification data 11 transferred through the relay bus 1 is received by the communication module 3.

  The collation means 33 of the communication module 3 collates the function (master module / slave module) of the communication module 3 set by the internal switch 31 with the function indicated by the identification data 11 transmitted from the communication module 2.

  For example, in the case illustrated in FIG. 1, it is determined that the communication module 2 functions as a master module based on the identification data 11. Further, based on the state of the internal switch 31, the communication module 3 is recognized as functioning as a slave module. For this reason, the collation result in the collation means 33 is “normal”. On the other hand, if the setting of the internal switch 21 or the internal switch 31 is incorrect, the functions of the communication module 2 and the communication module 3 are both determined to be the master module or the slave module. It becomes "abnormal". In this case, the output of data from the communication module 3 to the bus 5 is stopped by the stop unit 34, and adverse effects on the system are suppressed.

  On the other hand, in the example of FIG. 2B, data transfer from the bus 5 to the bus 1 is shown, and “data C” and “data D” transferred through the bus 5 have a certain delay time. To the relay bus 1.

  The transmission means 32 of the communication module 3 outputs identification data 12 for identifying the function (master module / slave module) of the communication module 3 set by the internal switch 31 to the relay bus 1. For example, when the internal switch 31 is in the state shown in FIG. 1, the identification data 12 indicating the function as a slave module is output. Since the communication frequency of the relay bus 1 is 64 MHz, as shown in FIG. 2B, the “data C” and “data D” transferred through the bus 5 at 32 MHz are compressed to ½ time length. Thus, the identification data 12 can be inserted into the transfer data.

  The identification data 12 transferred through the relay bus 1 is received by the communication module 2.

  The collation unit 23 of the communication module 2 collates the function (master module / slave module) of the communication module 2 set by the internal switch 21 with the function indicated by the identification data 12 transmitted from the communication module 3.

  For example, in the case shown in FIG. 1, it is determined that the communication module 3 functions as a slave module based on the identification data 12. Further, based on the state of the internal switch 21, it is recognized that the communication module 2 functions as a master module. For this reason, the collation result in the collation means 23 is “normal”. On the other hand, if the setting of the internal switch 21 or the internal switch 31 is incorrect, the functions of the communication module 2 and the communication module 3 are both determined to be the master module or the slave module, and the verification result in the verification unit 23 is “ It becomes "abnormal". In this case, the output of data from the communication module 2 to the bus 4 is stopped by the stop unit 24, and adverse effects on the system are suppressed.

  As the identification data, a pattern that does not appear as normal transfer data (for example, “data A”, “data B”, “data C”, or “data D”) may be selected.

  Further, the data transfer order is not limited to the example of FIGS. 2 (a) and 2 (b). For example, the transfer order of “data A” and identification data 11 may be switched, and the identification data may be transferred first.

  As described above, according to the communication system of the present embodiment, the setting status of each communication module can be confirmed without requiring a complicated system design or a large-scale change as in the case of CRC check. , The reliability of the system can be improved. Further, there is no delay in data transfer. Furthermore, since the function verification is performed substantially in real time, if there is an error in the setting status, the data transfer is immediately stopped, and adverse effects on the system can be minimized.

  In the above embodiment, the communication frequency of the relay bus 1 is twice the communication frequency of the bus 4 and the bus 5, but the communication frequency of the relay bus 1 can be arbitrarily determined. For example, it may be an integral multiple (three times or more) of the communication frequency of the bus 4 and the bus 5. Further, the number of bits of the relay bus 1 may be larger than the number of bits of the bus 4 and the bus 5. In this case, the communication frequency of the relay bus 1 may be the same as or different from the bus 4 and the bus 5.

  Furthermore, the communication frequency and the number of bits of the relay bus can be arbitrarily set within a range in which the data transfer amount per unit time of the relay bus can be expanded. What is necessary is just to comprise so that identification data can be inserted in the transfer data of a relay bus | bath.

  In the above embodiment, the master module / slave module is switched by switching the setting of the same module. However, each module may be prepared as a dedicated machine. In this case, when an incorrect module is connected, the collation result in the collation means may be “abnormal”. In addition, as shown in the said embodiment, it becomes possible to reduce development cost by making a master module and a slave module into a common module.

  Further, in the above embodiment, function verification is performed between two communication modules. However, function verification may be performed between three or more communication modules. In this case, the communication frequency and the number of bits can be appropriately selected in order to secure the transfer amount necessary for transferring the identification data.

  Further, when there are a plurality of types of data to be indicated by the identification data, the type may be indicated by the timing at which the identification data is inserted. Depending on where the identification data is inserted in the transfer data transferred through the relay bus, it is possible to indicate a plurality of different types while using common identification data (pattern).

  As described above, according to the communication system of the present invention, the function transmitted by the transmission unit and the function recognized by the second recognition unit are collated, so that the communication module can be used without complicating the system. You can quickly check the setting status and connection status. In addition, when the collation result is abnormal, the adverse effect on the system can be minimized by stopping the data transfer.

  The scope of application of the present invention is not limited to the above embodiment. The present invention can be widely applied to a communication system configured by connecting a plurality of communication modules through a relay bus.

The block diagram which shows the structure of the communication system of one Embodiment. The timing diagram which shows the communication timing of the data via a relay bus. The block diagram which shows the structure of the conventional communication system. The timing diagram which shows the communication timing of the data in the conventional communication system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Relay bus 2 Communication module 3 Communication module 21 Internal switch (1st recognition means, 2nd recognition means, switching means)
22 transmitting means 23 collating means 24 stopping means 31 internal switch (first recognizing means, second recognizing means, switching means)
32 Transmitting means 33 Verification means 34 Stopping means

Claims (7)

In a communication system configured by connecting a first communication module and a second communication module via a relay bus,
The first communication module includes:
First recognition means for recognizing the function of the first communication module;
Transmitting means for transmitting the function recognized by the first recognition means to the second communication module via the relay bus;
Comprising
The second communication module includes:
Second recognition means for recognizing the function of the second communication module;
Collating means for collating the function transmitted by the transmitting means with the function recognized by the second recognizing means;
A communication system comprising: The first communication module and the second communication module are configured as a common communication module,
The common communication module is:
It functions as the first recognition unit and the second recognition unit, and the function of the common communication module is between the function as the first communication module and the function as the second communication module. A communication system comprising switching means for switching. A first bus for communication with an external module is connected to the first communication module, and a second bus for communication with an external module is connected to the second communication module, respectively. And
The communication system according to claim 1 or 2, wherein a communication frequency of the relay bus is set higher than a communication frequency of the first bus and a communication frequency of the second bus. 4. The communication system according to claim 3, wherein a communication frequency of the relay bus is an integral multiple of a communication frequency of the first bus and the second bus. The communication system according to any one of claims 1 to 4, wherein the number of bits of the relay bus is larger than the number of bits of the first bus and the second bus. The communication system according to claim 1, further comprising a stop unit that stops outputting data from the second communication module in accordance with a collation result in the collation unit. The communication system according to any one of claims 1 to 6, wherein the function of the first communication module and the function of the second communication module are functions as a master module or a slave module, respectively. .

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