JPH0514305A - Multiplexer and network system using the multiplexer - Google Patents

Abstract

PURPOSE:To quicken the reply to a monitor by sending the reply signal through the use of an idle area. CONSTITUTION:The multiplexer is used for a network system provided with a monitor and the multiplexer has an address number to receive a reception signal via a reception line. The reception signal has a signal frame and a prescribed area of the signal frame included a command signal having an address code. The multiplexer is provided with a 1st detection section 47b generating a coincidence signal when the address code is coincident with the address number in response to the command signal and 2nd detection sections 47e, 47e generating a position signal representing the location of an idle area when the idle area is in existence in the signal frame and generates the reply signal based on the command depending on the coincidence signal and generates a transmission signal by inserting the reply signal to the idle area based on the position signal and sends the transmission signal to a transmission line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplexer used in a network system.

[0002]

2. Description of the Related Art Conventionally, a system including a main multiplexer and first to Nth multiplexers is known as a network system (where N is a natural number). In such a network system, the multiplexers are connected to each other in a cascade and communicate with each other by a multiplexed signal. The main multiplexer and the first to Nth multiplexers respectively have a main address number and first to Nth address numbers. Further, such a network system further has a monitoring device which is connected to the main multiplexer and monitors the main multiplexer and the first to Nth multiplexers.

When monitoring the main multiplexer and one of the first to Nth multiplexers, the monitor generates a command signal. This command signal includes a command for collecting monitoring information from each monitoring device and an address code corresponding to each multiplexing device.

In response to a command signal provided in the multiplexed signal form, each multiplexer generates a response signal (monitoring information) when each address number matches the address code. Such a response signal is positioned in a predetermined time slot of the multiplexed signal in each multiplexing device and sent to the monitoring device.

[0005]

However, in the state where the above-mentioned predetermined time slot is already used by another multiplexer, the multiplexer cannot send the response signal, and as a result, the predetermined signal cannot be transmitted. Until some time slot is empty, some multiplexers must inevitably wait for a response signal to be sent to the monitor. Therefore, it is difficult to quickly transmit the response signal to the monitoring device.

An object of the present invention is to provide a multiplexing device and a network system capable of quickly transmitting a response signal to a monitoring device.

[0007]

According to the present invention, there is provided a multiplexing device having a receiving section having an address number and receiving a reception signal via a reception line, and a transmission section for transmitting a transmission signal to the transmission line. The received signal includes a signal frame and carries a command signal having a command and an address code in a predetermined area of the signal frame, and the receiving unit responds to the command signal by setting the address code to the address number. First detecting means for detecting whether or not they match and sending a detection signal when they match, and checking whether or not there is a vacant area in the signal frame, and if there is a vacant area, indicates the position of the vacant area. Second detection means for transmitting a position signal, response signal generation means for generating a response signal in response to the command, and the response signal in response to the detection signal And a supply unit for supplying the transmission unit, wherein the transmission unit has an insertion unit for generating the transmission signal by inserting the response signal into the empty area in response to the position signal. And a network system using the multiplexer.

[0008]

EXAMPLES The present invention will be described below with reference to examples.

Referring to FIG. 1, the illustrated network system includes a plurality of multiplexing devices 10 to 12, a plurality of communication devices 13 to 16 and a monitoring device 17. Here, for convenience of description, the communication devices 13 to 16 are used.
Is a multiplexer. The multiplexing devices 10 to 16 are located downstream with respect to the monitoring device 17.
Further, the monitoring device 17 is directly connected to the multiplexing device 10 via the monitoring line 17a. As shown, the multiplexer 17 is located upstream with respect to the remaining multiplexers 11-16. Here, the multiplexer 17 will be referred to as a main multiplexer. Furthermore, the multiplexers 11 to 1
6 will be referred to as first to sixth multiplexers, respectively.

As shown, the first multiplexer 11 is connected to the main multiplexer 10 via a communication line 11a and the second multiplexer 12 is first multiplexed via a communication line 12a. It is connected to the device 11. Here, communication line 1
1a and 12a are multiplexed lines. Similarly, the third
And the fourth multiplexers 13 and 14 are connected to the main multiplexer 10 and the first multiplexer via communication lines 13a and 14a, respectively, and the fifth and sixth multiplexers 15 and 15 are connected.
And 16 are connected to the fourth multiplexer 14 via communication lines 15a and 16a, respectively.

The multiplexing devices 10 to 16 are partially different in structure and operation from each other as will be described later, but the main structure and operation are substantially the same. Each of the multiplexers 10 to 16 receives a received signal from the multiplexer located on the upstream side or the downstream side, and sends a transmission signal to the multiplexer located on the upstream side or the downstream side. Each of the received and transmitted signals may be a multiplexed signal.

Referring to FIG. 2 together with FIG. 1, it is assumed that the illustrated network system operates as a conventional network system in order to facilitate understanding of the present invention. The monitor 17 sends a command signal to the main multiplexer 10 to collect the monitor information from each of the multiplexers 10 to 16. This command signal contains an address code for specifying one of the multiplexers.

Although this command signal is not multiplexed when it is sent from the monitoring device 17 to the main multiplexing device 10,
When it is sent to the downstream side, it is multiplexed by each of the multiplexers 11 to 16. In any case, the predetermined multiplexing device directly or indirectly sends the monitoring information to the monitoring device 17 as a response signal. Then, the response signal is received by the monitoring device 17 in a final demultiplexed state without being multiplexed by a predetermined multiplexing device.

When each reception signal and each transmission signal are transmitted through the communication lines 11a to 16a shown in FIG. 1, each reception signal and each transmission signal have the signal frame (signal format) shown in FIG. . The illustrated signal frame has a predetermined length, and includes a frame synchronization area F, a signal transmission area T, a monitoring information area M, and an empty area (unused area) U.
have. Frame synchronization area F and signal transmission area T
Is given a frame synchronization signal and a transmission signal, and the monitoring information area M is given a command signal or a response signal.
The monitoring information area M has a fixed length.

From the above description, it can be seen that the command signal or the response signal is assigned to a predetermined position of each frame at the time of multiplexing in each multiplexer in the conventional network. In the above configuration, when collecting response signals from a plurality of multiplexers, the response signals are transmitted by the multiplexers 10 and 1
1 may collide with each other. The probability of such collisions of response signals is quite high in a multiplexer located near the monitoring device 17. Further, the conventional network system has the problems as pointed out at the beginning of this specification.

A network system according to the present invention will be described with reference to FIG. 3 in addition to FIG. This network system has the main multiplexer 10, the first to sixth multiplexers 11 to 16 and the monitor 17 shown in the conventional network system. Here, each of the multiplexers 10 to 16 is different from the multiplexer shown in the conventional network system. Here, the multiplexer shown in FIG. 3 is the main multiplexer 10
Alternatively, it is used as any one selected from the first to sixth multiplexers 11 to 16.

Similar to the conventional network system, the monitoring device 17 is provided with a command supply circuit 17b for supplying the main multiplexer 10 with the same command signal as the command signal described in the conventional network system. Therefore, the command signal includes a command for instructing transmission (transfer) of a response signal from each of the multiplexers 10 to 16 to the monitoring device 17, and a predetermined address code assigned to a predetermined one of the multiplexers 10 to 16. Will be equipped with.

Referring to FIG. 3, first, a multiplexer used as the main multiplexer 10 will be described. As shown in FIG. 1, the main multiplexer 10 includes first and third multiplexers 11 and 13 and a monitor 17 to a communication line 11 respectively.
Received signals are received via a and 13a and the monitoring line 17a. On the other hand, the main multiplexer 10 has the first and third
A transmission signal is sent to the multiplexing devices 11 and 13 and the monitoring device 17. The received signal given from the supervisory signal is not multiplexed and this received signal is a command signal. The remaining received signals are multiplexed signals in the illustrated example. Similarly, the received signal given to the supervisory signal is not multiplexed, and this received signal is a response signal. The remaining transmitted signals are multiplexed signals in the illustrated example.

The main multiplexer 10 includes receiving circuits 211 to 2
1N, and the number of receiving circuits 211 to 21N is equal to the number of communication lines 11a and 13a connected to the main multiplexer 10.
Is equal to the number of receivers (only two receiver circuits 21 in FIG. 3).
Only 1 and 212 are shown). Here, N is a natural number. Each receiving circuit 211 and 212 receives multiple received signals. Further, the main multiplexer 10 is provided with a command receiving circuit 22 and a response sending circuit 23 shown by broken lines in FIG. The command receiving circuit 22 receives a command signal from the monitoring device 17. The response sending circuit 23 sends a response signal to the monitoring device 17. Although only two sets are shown in FIG. 3, each of the main multiplexers 10 has transmission circuits 311 to 31 for transmitting a multiplex transmission signal.
N, frame synchronization circuits 421 to 42N, and separation circuits 431 to 43N.

The receiving circuits 211 to 21N have the same structure and operation as each other, and further, the transmitting circuits 311 to 31.
N, the frame synchronization circuits 421 to 42N, and the separation circuits 431 to 43N have the same structure and operation. Considering this point, here, the receiving circuit 2 is mainly used.
11, the frame synchronization circuit 421, and the separation circuit 431 will be described.

In the above-mentioned configuration, the multiplex received signal is passed through the receiving circuits 211 to 21N and the frame synchronizing circuit 421.
To 42N and separation circuits 431 to 43N.
Each of the separation circuits 431 to 43N includes a frame synchronization circuit 42.
The response signal is separated from each multiplex received signal by referring to the frame synchronization signal detected at 1 to 42N, and the response signal is sent to the selection circuit 46 and the control circuit 47. Further, the demultiplexing circuits 431 to 43N give the intermediate signal demultiplexed from the multiplex received signals to the multiplexing circuit 50.

The control circuit 47 controls the selection circuit 46 in response to the response signal. As a result, the selection circuit 46 selects the response signal and sends it to the switching circuit 48. On the other hand, the switching circuit 48 connects the response sending circuit 23 and the selection circuit 46 under the control of the control circuit 47 as described later. As a result,
The response signal is sent from the response sending circuit 23 to the monitoring device 17 through the monitoring line 17a.

The plurality of intermediate signals are multiplexed with the first internal multiplexed signal by the multiplexing circuit 50 and sent to the time division switch 51. In the time division switch 51, the second demultiplexing circuit 5 is generated from the first demultiplexing signal by the time division method under the control of the time division control circuit 49.
Give to 2. Then, the demultiplexing circuit 52 demultiplexes the second internal multiplexed signal into the first and second local signals, and sends them to the transmitting circuits 311 and 312, respectively. Transmission circuit 31
Reference numerals 1 and 312 denote the first and third multiplexers 11 using the first and second local signals as transmission signals based on the frame signal provided from the frame signal generator 53.
And 13 are sent.

Main multiplexing apparatus 10 will be described below with reference to FIG. 4 together with FIG. When the monitoring device 17 monitors a specific one of the main monitoring device 10 and the first to sixth multiplexing devices 11 to 16, a command having a specific address code from the command supply circuit 17a to the main multiplexing device 10. A signal is given. The command signal is received by the command receiving circuit 22, and the selection circuit 46 and the control circuit 47 are received.
Given to.

In FIG. 4, the control circuit 47 includes a judgment unit 47.
a, address comparison unit 47b, address generator 47c, message generation unit 47d, control unit 47e, and storage unit 47.
e. As will be described later with respect to the first multiplexer 11, such a storage unit 47f is used in each of the other multiplexers 11 to 17 as necessary, but the storage unit 4f is not necessarily used in the main multiplexer 10.
7e may not be needed. The determination unit 47a determines whether the signal supplied here is a command signal or a response signal. Specifically, when the supplied signal is a command signal, the determination unit 47a causes the address comparison unit 47b.
Send this command signal to. If the supplied signal is the response signal, the determination unit 47a outputs the determination result signal to the control unit 47e.
Send to. The address generator 47c generates a main address number and supplies the main address number to the address comparison unit 47b. Free space information indicating the free space U is stored in the storage unit 47f.

When the command signal is given, the address comparing section 47b compares the specific address code with the main address number to check whether the specific address code and the main address number match. Then, when the specific address code and the main address number match, the address comparison unit 47b outputs the command included in the command signal to the message generation unit 47.
give to d. Further, the address comparison unit 47b is connected to the control unit 4
The first detection signal (coincidence signal) is given to 7e. The message generator 47d generates a main message based on the command and supplies it to the selection circuit 46 as a main response signal.

The control unit 47e controls the selection circuit 46 according to the coincidence signal, and as a result, the selection circuit 46 gives the main response signal to the switching circuit 48. Further, the control unit 47e controls the switching circuit 48 according to the coincidence signal so that the switching circuit 48 connects the selection circuit 46 and the response sending circuit 23. As a result, the main response signal is sent from the response sending circuit 23 to the monitoring device 17.

On the other hand, if the specific address code does not match the main address number, the address comparison section 47b sends a second detection signal (mismatch signal) to the control section 47e. Control unit 47
The e controls the selection circuit 46 according to the non-coincidence signal, whereby the selection circuit 46 selects the command signal and sends it to the switching circuit 48. Further, the control unit 47e controls the switching circuit 48 according to the non-coincidence signal, so that the selection circuit 48 connects the selection circuit 46 and the transmission circuits 311 and 312. As a result, the command signal is sent to the transmission circuits 311 and 312, where the command signal is based on the frame signal and the monitoring information area M
And the transmission signal is sent to the first and third multiplexers 11 and 13.

On the other hand, when the signal given to the judging section 47a is a response signal, the judging section 47a sends a judgment result signal to the control section 47e. In response to the determination result signal, the control unit 47e controls the selection circuit 46, and the selection circuit 46 sends a response signal to the switching circuit 48. Furthermore, the control unit 47e
Then, the switching circuit 48 is controlled to connect the selection circuit 46 and the response sending circuit 23 by the switching circuit 48. As a result, the response signal is sent from the response sending circuit 23 to the monitoring device 17.

Next, the first multiplexer 11 will be described with reference to FIGS. In FIG. 3, the first multiplexer 11 is a command receiving circuit 2 shown by a broken line in FIG.
2 and the response sending circuit 23 are not required. That is, the first
Of the main multiplexer 10 except that it does not include the command receiving circuit 22 and the response sending circuit 23.
It has the same configuration as. As described above, the first multiplexer 11 is the main multiplexer 10 and the second multiplexer 1
2 and the fourth multiplexer 14. Therefore, although only two sets are shown in FIG. 3, the first multiplexer 11 includes three receiving circuits 211 to 21N, three transmitting circuits 311 to 31N, frame synchronizing circuits 421 to 42N, and a demultiplexing circuit. Circuits 431 to 4
Equipped with 3N. The control circuit of the first multiplexer 11 has the same configuration as the control circuit shown in FIG.

The first multiplexer 11 receives the multiplex received signal at the receiving circuit 211. In the illustrated example, this multiplex received signal is equal to the multiplex transmitted signal sent from the sending circuit 311 of the main multiplexer 10. Therefore, this multiplex received signal carries the command signal. Main multiplexer 10
As described above, the separation circuit 431 separates the command signal from the multiplex reception signal by referring to the frame synchronization signal detected by the frame synchronization circuit 421 and selects the selection circuit 4.
6 and the control circuit 47.

The control circuit 47 of the first multiplexer 11 will be described with reference to FIG. 4 together with FIG. When the command signal is sent, the judgment unit 47a sends the command signal to the address comparison unit 47a as described with respect to the main multiplexer 10. In the first multiplexer 11, the address generator 47c generates a first address number and sends the first address number to the address comparing section 47b. When the specific address code carried by the command signal matches the first address number, the address comparing section 47b gives the command included in the command signal to the message generating section 47d. Further, the address comparison unit 47
b sends the first detection signal to the control unit 47e. The message generator 47d generates a first message based on the above command and sends the first message to the selection circuit 46 as a first response signal.

On the other hand, the control unit 47e controls the selection circuit 46 to be the first circuit.
Control based on the detection signal of
Response signal is selected and the first response signal is sent to the switching circuit 48. Further, the control unit 47e controls the switching circuit 47 based on the first detection signal to connect the selection circuit 46 and the sending circuit 311 by the switching circuit 47. As a result, the first response signal is sent to the main multiplexer 10.

When receiving the first detection signal, the control section 47e accesses the storage section 47f to detect the position of the empty area U in the signal frame. When the empty area U exists in the signal frame, the control unit 47e gives the position signal indicating the position of the empty area U in the signal frame to the time division control circuit 49. As a result, the time division control circuit 49 controls the time division switch 51 so that the time division switch 51 uses the time division method to convert the first internal multiplexed signal into the second signal.
To generate the internal multiplex signal of.

The first multiplexer 11 is the main multiplexer 10
Since it is possible to communicate with the second and fourth multiplexers 14, the second internal multiplex signal is transmitted by the demultiplexing unit 52 to the first demultiplexing unit 52.
To the third local multiplex signal.
Then, the first local multiplexed signal is sent to the sending circuit 311. The sending circuit 311 first writes the empty area U based on the frame signal given from the frame signal generator 53.
Locate the response signal of.

Then, the sending circuit 311 gives the multiplex transmission signal including the first response signal to the main multiplexing circuit 10.

On the other hand, when the specific address code does not match the first address number, the address comparison section 47b sends a second detection signal to the control section 47e. The control unit 47e controls the selection circuit 46 according to the second detection signal, selects the command signal by the selection circuit 46 and sends it to the switching circuit 48. Further, the control unit 47e controls the switching circuit 48 based on the second detection signal so that the switching circuit 48 connects the selection circuit 46 and the sending circuits 312 and 313. Sending circuit 31
In 2 and 313, the command signal is positioned in the monitoring information area M based on the frame signal, and the multiplex transmission signal including the command signal is transmitted to the second and fourth multiplexers 1 respectively.
Send to 2 and 14. The second to sixth multiplexers 12 to 16 have the same configuration as the first multiplexer 11.
As is clear from the description of the first multiplexer 11, when the multiplex reception signal including the command signal is received, the second
The sixth to sixth multiplexers 12 to 16 operate in the same manner as the first multiplexer 11.

In the first multiplexer 11, when the judgment result signal is given from the judgment unit 47a to the control unit 47e,
The control unit 47e controls the selection circuit 46 to provide the switching circuit 48 with a response signal sent from the second multiplexer 12 and one of the fourth to sixth multiplexers 14 to 16 by the selection circuit 46. . Further, the control unit 47e includes a switching circuit 48
The switching circuit 48 connects the selection circuit 46 and the sending circuit 311 to give a response signal to the sending circuit 311.

In this case, the control unit 47e accesses the storage unit 47f to check the empty area U in the signal frame, and when the empty area U exists, gives a position signal to the time division control circuit 49. In response to the position signal, the time division control circuit 49 controls the time division switch 51 to generate the second internal multiplex signal from the first internal multiplex signal by the time division method.

As described above, the second internal multiplex signal is demultiplexed by the demultiplexing circuit 52 into the first to third local multiplex signals, and the first local multiplex signal is sent to the sending circuit 311. The sending circuit 311 positions the response signal in the empty area based on the frame signal, and sends the multiplex transmission signal including the response signal to the main multiplexer 10.

As is apparent from the above description, when the multiplex reception signal including the response signal is received, the fourth multiplexing device 14
Operates in the same manner as the first multiplexer 11.

[0042]

As described above, according to the present invention, the response signal (monitoring information) is transmitted by using the empty area in the signal frame. Therefore, the maximum area is allocated for monitoring information by the line setting. You can Therefore, there is an effect that the response time between the monitoring device and the multiplexing device can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a network system having a plurality of multiplexing devices and one monitoring device.

FIG. 2 is a diagram showing a signal frame of a multiplexed signal used in the network system shown in FIG.

FIG. 3 is a block diagram showing an embodiment of a multiplexer according to the present invention used in the network system shown in FIG.

FIG. 4 is a block diagram showing an embodiment of a control circuit used in the multiplexing device shown in FIG.

[Explanation of symbols]

211-21N receiving circuit 22 Command receiving circuit 23 Response sending circuit 311 to 31N sending circuit 421-42N Synchronous circuit 431-43N separation circuit 46 selection circuit 47 control circuit 48 switching circuit 49 Time division control circuit 50 Multiplexing circuit 51 time division switch 52 Demultiplexing circuit 53 frame signal generator

Claims (3)

[Claims] 1. A multiplexing device comprising: a receiver having an address number and receiving a reception signal via a reception line; and a transmission unit transmitting the transmission signal to a transmission line, wherein the reception signal includes a signal frame. A command signal having a command and an address code is carried in a predetermined area of the signal frame, and the reception unit responds to the command signal by detecting whether or not the address code matches the address number and matches them. And a second detecting means for transmitting a position signal indicating the position of the vacant area when there is a vacant area. A response signal generating means for generating a response signal in response to the command, and a supplying means for supplying the response signal to the transmitting section in response to the detection signal. In the multiplexing device, the transmitting unit has an inserting unit that inserts the response signal into the empty area in response to the position signal to generate the transmission signal. 2. A main multiplexer having a main address number and a monitoring device capable of communicating with the main multiplexer and monitoring the main multiplexer, wherein the main multiplexer is connected via a main reception line. In a network system having a receiving unit for receiving a reception signal and a transmission unit for transmitting a transmission signal to a main transmission line, the monitoring device supplies a command signal having a command and an address code to the main multiplexing device. The receiving unit receives the command signal, and in response to the command signal, checks whether or not the address code matches the main address code and sends a match signal when they match, and a non-match In this case, the transmission unit has a detection means for transmitting a non-coincidence signal and a response signal generation means for generating a main response signal in response to the command. In response to the supply of the main response signal to the monitoring device, and multiplexing for multiplexing the received signal and the command signal in response to the non-coincidence signal and sending the multiplexed signal as the transmission signal to the transmission line. A network system having means. 3. The network system according to claim 2, further comprising a slave multiplexer capable of communicating with the master multiplexer, the slave multiplexer including a slave address number and transmitting the transmission signal. The slave reception unit receives as a reception signal via the transmission line, and the slave transmission unit transmits the slave transmission signal to the slave transmission line. The slave reception signal includes a signal frame and a predetermined area of the signal frame. The first detecting means for carrying the command signal, and the sub-reception unit, in response to the command signal, checks whether or not the address code matches the sub-address number, and sends a coincidence signal when they match. A second detection means for sending out a position signal indicating the position of the empty area when there is an empty area, and for responding to the command. A slave response signal generating means for generating a slave response signal, and a slave supply means for supplying the slave response signal to the slave transmitting section in response to the coincidence signal, wherein the slave transmitting section responds to the position signal. Then, the network system has an inserting means for inserting the slave response signal into the empty area to generate the slave transmission signal.