JPH03201750A - Transmission line test system for loop communication system - Google Patents

Abstract

PURPOSE:To quicken the operation confirmation of a transmission line at adjustment and maintenance by providing a test mode confirming whether or not the transmission line is operated normally and constituting the frame with a connection control part at the test mode so as to make communication. CONSTITUTION:A frame is constituted by only a simultaneous area and a connection control area 51 in the test mode where whether or not the transmission line is normally operated is confirmed at the adjustment or maintenance of the system and the connection control area 51 is used to apply loopback communication or opposite communication. That is, the end of the connection area 51 is set to the final slot at the test mode to allow a CPU 7 to generate and send various data in an optional slot in the connection control packet and the connection control packet after circulation of the loop is received to compare data. Thus, the transmission line including a transmitter 15 and a receiver 1 of each station and a cable is confirmed. Thus, the operation of the transmission lien is quickly confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a transmission line testing method for a loop communication system that can be applied to a large-scale loop network.

(Prior art) With the development of the information society, network systems that connect multiple information systems (stations) to each other via data transmission paths and realize more advanced information processing are becoming popular, such as process control network systems and Various types of network systems have been developed, such as OA network systems and factory automation network systems.

Incidentally, recent trends call for the development of large-scale, sophisticated networks that integrate or combine various independently existing networks to enable even more sophisticated information processing. The basic requirements for such a large-scale network are: (1) It must be an advanced and long-distance network; (2)
It must be a multimedia network that can handle various media such as audio, still images, videos, and coded data; (3) It must be able to integrate circuit switching and packet switching; (4) It must be able to accommodate a wide variety of terminals. It is possible to connect various types of networks as branch lines.

In order to meet these demands, we have developed a transmission line that has excellent compatibility with circuit switching and packet switching, and that is easy to use optical communication technology and easy to construct large-scale network systems, for example, as shown in Figure 3. A loop communication system in which each station is connected in a loop through a communication network is attracting attention.

Also, as the frame format, for example, the 4th
As shown in the figure, a frame with a fixed period is divided into a synchronization area 50, a connection control area 51, a circuit switching area 52, and a packet switching area 53. It is considered that they can be used depending on their characteristics. Furthermore, as shown in FIG. 5, it is naturally possible to eliminate the packet exchange area 53.

Note that line switching is realized by providing a large number of slots in the line switching area 52, allocating the slots according to requests from terminals, and allowing the terminals to communicate using the allocated slots. Control data for allocating slots is communicated using, for example, a connection control area 51 set by dividing the frame.

FIG. 6 shows such a connection control area 51 in detail. In the figure, A shows an example of the format when circuit switching and packet switching are integrated, and B shows an example of the format when only circuit switching is used. .

Format A includes a synchronization area 50, an n-channel connection control area 51, a circuit switching area 52, and a packet switching area 53.
Consisting of Format B is the synchronization area 50. It consists of an n-channel connection control area 51 and a line switching area 52.

Each channel in the connection control area 51 of formats A and B described above is set to a different band, and each channel is used individually to communicate connection control packets between the control station and each station, and between each station. ing.

Note that the number of channels and the area of the connection control area 51 to be divided and set are optimally set according to the system scale such as the number of terminals accommodated in the network, the length of the connection control packet, etc. It is.

Settings may be made, for example, by setting the system configuration, particularly the number of channels and the band. In this example, the connection control area 51 is made up of a plurality of channels, but it goes without saying that the number of channels may be just one.

Furthermore, the format of the channel in the connection control area 51 is as follows:
For example, as shown in C in FIG. 6, it is composed of an empty/cold state flag of the channel, a destination station flag, a communication station flag, data, and its check code. Using such a channel, connection control data is communicated as shown in FIG. 7, and the incoming and outgoing calls are controlled. Connection control data is generally short data, and a large amount of this data is generated in a large-scale network.

Therefore, in order to prevent one station from continuing to occupy a channel, an access method is adopted in which the size of the data portion of the channel is set larger than the connection control data, and the channel is released after one communication. In other words, each station is
A transmission spatiotemporal channel is acquired and transmitted, and when the used channel is returned, the channel is released. Therefore, one station does not continue to occupy the channel and use it, and each station is provided with a fair opportunity to access the channel.

FIG. 8 shows an example of the configuration of a station that communicates connection control data via such a channel.

The configuration of this station and its functions will be explained. One frame of data received by the receiver 1 is taken into the serial/parallel conversion circuit 2 and supplied to the connection control section 3, line switching section 4, and packet switching section 5, respectively. These connection control section 3, line switching section 4, and packet switching section 5 are connected to the CPU bus 6.
Data is sent and received between the CPU 7 and the memory 8 via the CPU 7 and the memory 8 to perform their respective functions.

The frame synchronization detection circuit 9 detects the synchronization area 501. : The head of the frame is detected from the input synchronization signal, and at this detection timing, the reception timing generation circuit 10 is activated and the slot counter 11 is initialized. This slot counter 11 counts the word clock generated by the reception timing generation 1M circuit 1o and detects the timing of each slot.

According to the slot timing signal generated by the slot counter 11, the connection control section 3 and the line exchange section 4 described above
, the packet switching unit 5 knows the manual timing of the corresponding received data and performs manual processing of the data.

Further, under the control of the transmission timing generation circuit 12, the transmission data from this station is selectively transmitted via the selector 13 from the connection control section 3, line switching section 4, and packet switching section 5, that is, in the above-mentioned format. The signal is timing-controlled and applied to the parallel-serial switching circuit 14, and then transmitted from the transmitter 15.

The selector 13 selects the signal received via the serial/parallel switching circuit 2 and supplies it to the parallel/serial switching circuit 14 when there is no transmission data from the station.

This selector 13 allows communication data to bypass analgesia.

By the way, the connection control section 3 is configured as shown in FIG. 9, for example. That is, the connection control area detection unit 21 detects the connection control area 51 of the received frame from the slot number detected and output by the slot counter 11. By detecting the connection control area 51, the data in the connection control area 51 in the received data is taken into the reception latch circuit 22.

The data taken into this reception latch circuit 22 is used in an empty channel detection circuit 23 to detect an empty channel, and a DA monitoring circuit 24 detects whether or not the data is addressed to the own station. ing.

If the data is addressed to the own station, the reception control unit 2
5 is activated and the received data stored in the receive latch circuit 22 is transferred to the receive buffer 26 and taken in by the CPU 7.

In this way, the connection control data communicated from the control station or another station is taken into the station and used for data communication control of the station.

On the other hand, when the station transmits, two transmission control units are activated under the control of the CPU 7. When the transmission control section 29 receives the transmission command from the CPU 7, it waits for a detection signal from the empty channel detection section 23. Upon receiving the detection signal, the transmission control unit 2
One is to generate a transmission request and provide it to the transmission timing generation circuit 12, and also to send it to the idle state flag generation section 32.
And a transmission timing signal is applied to the transmission buffer circuit 30 and the transmission latch circuit 31. As a result of this, the connection control data previously set in the transmission buffer circuit 30 according to the empty state flag indicating that the channel is in use and the calling request from the station is transferred to the transmission latch circuit 31, and this transmission latch circuit 31 is activated as described above. The connection control data is sent out via the selector 13.

After completion of such transmission, when the transmission control section 29 detects the return of the channel based on the signal from the connection control area detection section 21, it activates the empty status flag generation section 32 to release the channel.

As described above, the connection control section 3 connects the connection control area detection section 2
It is active and operates during the period when 1 is detected and output. The connection control detection section 21 is configured as shown in FIG. 10, for example. That is, the comparator 211 compares the slot counter 11
The slot number detected and output by the CPU 7 is inputted and compared with the output of the end register 212, which is the end slot number of the connection control area 51 set in advance by the CPU 7 at the time of system configuration. The output of the comparator 211 remains active until the slot number becomes larger than the output of the end register 212, and during this active period, the connection control area 5
1 is detected.

By the way, in general, in a loop communication system, the operation of the transmission line including the control station, the transmitter 15 and the receiver 1 housed in a plurality of stations, and the cables that connect these in a loop is checked by a certain station. This is done by transmitting data to a slot, receiving data from any slot that returns after going through a loop, and comparing the transmitted data and received data. Or something similar is done between stations.

However, in this system, since a frame is composed of a synchronization area 50, a connection control area 51, a circuit switching area 52, and a packet switching area 53, access to slots is distributed, and transmission paths are used during adjustment and maintenance. There is a problem that the operation check becomes complicated and requires +01 hours.

In other words, each area is a different world, and access to slots is hidden at each area corner. Therefore, for example, in order to access a slot in the circuit switching area 52, a terminal connected to the circuit switching is required, such as a bucket!
- In order to access the slots in the exchange area 52, a terminal connected to the packet exchange is required. Even when the terminal is not used, the CPU 7 must simultaneously access the connection control unit 3, line-of-sight exchange unit 4, and packet exchange unit 5, and generate various data in arbitrary slots of the frame to check the operation of the transmission path. The smoothing process becomes very complicated.

(Problem to be Solved by the Invention) As shown in 2, since the frame is composed of a synchronization area 50, a connection control area 51, a circuit switching area 52, and a packet switching area 53, access to slots is distributed, and adjustment and There is a problem that checking the operation of the transmission line during maintenance becomes complicated and takes time.

The present invention has been made to solve these problems, and it is an object of the present invention to provide a transmission line testing method for a loop communication system that can quickly confirm the operation of the transmission line during adjustment and maintenance. purpose.

[Structure of the Invention] (Means for Solving the Problems) A transmission path test method for a loop communication system of the present invention that achieves the above-mentioned object is such that a control station and a plurality of stations are connected in a loop through a transmission path. The control station circulates a frame consisting of a connection control area and a data communication area divided into a plurality of slots on the transmission path, and uses the connection control area to transmit connection 111j control packets between the stations. In a loop communication system that performs data communication between the stations using slots in the data communication area allocated by the connection control packet, a test is performed to confirm whether the transmission path is operating normally. The present invention is characterized in that a mode is provided, and in the test mode, the frame is composed only of the connection control area and communication is performed.

(Function) In the transmission line test method of the loop communication system of the present invention, a test mode is provided to confirm whether the transmission line is operating normally during system adjustment or maintenance.
In the test mode, a frame is made up of only a synchronization area and a connection control area, and by using the connection control area to perform return communication or one-way communication, the operation of the transmission path can be quickly confirmed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a connection control area detection section 21 of a station connection control section 3 of a loop communication system according to an embodiment of the present invention.

This station is constructed by adding a selector 213, a final slot number 214, and a test mode flag 215 to the conventional connection control area detection section shown in FIG. 10. Other station configurations are shown in FIGS. 8 and 9. Same as shown.

FIG. 2 shows the format of the frame in the test mode in this embodiment, showing the synchronization area 50 and the connection control area 51.
It consists of

In the normal mode, the comparator 211 selects the output of the end register 212 from the slot number detected and output by the slot counter 11 and the end slot number of the connection control area 51 set in advance by the CPU 7 during system configuration. Enter and compare via. Comparison part 2
11 output, slot number < A) is the output register 21
It becomes active until it becomes larger than the output (B) of 2,
The connection control area 51 is detected during this active period.

In the test mode, the comparator 211 compares the slot counter 11
The slot number (A) detected and output by the CPU 7 and the final slot number 214 (B) selected by the test mode flag 215 set by the CPU 7 are input via the selector 213 and compared. The output of the comparator 211 is the slot number (
A) remains active until it matches the final slot number 214 (B), and the connection control area 51 is detected during this active period. As a result, as shown in FIG. 2, all areas other than the synchronization area 50 become connection control areas 51. Note that the final slot number 214 may be set by either the switch or the CPU 7.

Connection 1 in this embodiment. The receiving operation of the sub-section is exactly the same as that shown in the conventional example. That is, the connection control area detection unit 21 detects the connection control area 51 of the received frame from the slot number detected and output by the slot counter 11. By detecting the connection control area 51, the data in the connection control area 51 in the received data is taken into the reception latch circuit 22.

The data taken into this reception latch circuit 22 is used in an empty channel detection circuit 23 to detect an empty channel, and a DA monitoring circuit 24 detects whether or not the data is addressed to the own station. Ru. If the data is addressed to the own station, it is transferred to the reception control section 25 and taken in by the CPU 7.

In this way, the connection control data communicated from the control station or another station is taken into the station and used for data communication control of the station.

On the other hand, when this station transmits, two transmission control units are activated under the control of the CPU 7. The transmission control unit 29 is a CPU
When receiving a transmission command from , it waits for a detection signal from the empty channel detection section 23 . Upon receiving the detection signal, the transmission control unit 2
First, it generates a transmission request and provides it to the transmission timing generation circuit 12, and also applies a transmission timing signal to the empty state flag generation section 32, the transmission buffer circuit 30, and the transmission latch circuit 31. As a result, the busy status flag indicating that the channel is in use and the connection control data that had been set in the transmission buffer in advance in accordance with the calling request from the station are transferred to the transmission latch circuit 31, which in turn controls the selector 13 described above. The connection control data will be sent through the connection control data.

After the end of such transmission, when the two transmission control units detect the return of the channel based on the signal from the connection control area detection unit 21, they activate the empty status flag generation unit 32 to release the channel. .

As described above, in this embodiment, by setting the end of the connection control area 51 to the last slot in the test mode llr, the CPU 7 generates and transmits various data to any slot in the connection control bucket, and performs loop- By receiving the patrol connection control packet and comparing the data, it is possible to confirm the transmission path including the transmitter 15 and receiver 1 of each station, cables, etc.

[Effects of the Invention] As explained above, according to the transmission line testing method of the loop communication system of the present invention, a test mode is provided to confirm whether the transmission line is operating normally during system adjustment or maintenance. In the test mode, a frame is composed of only a synchronization area and a connection control area, and the operation of the transmission path can be quickly checked by using the connection control area to perform return communication or opposite communication.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a connection control area detection section of a connection control section of a station in a loop communication system according to an embodiment of the present invention, FIG. 2 is a frame format diagram in the same embodiment, and FIG. The figure is a schematic diagram of the loop communication system, Figures 4, 5, and 6 are frame format diagrams, Figure 7 is an operation sequence diagram showing connection control operations, and Figure 8 is a station configuration. FIG. 9 is a block diagram showing the configuration of a connection control section of a station, and FIG. 10 is a block diagram showing the configuration of a conventional connection control area detection section. DESCRIPTION OF SYMBOLS 1... Receiver, 3... Connection control unit, 4... Line switching unit, 5... Packet switching unit, 7... CPU, 9...
...Frame synchronization detection circuit, 10...Reception timing generation circuit, 11...Slot counter, 12...Transmission timing generation circuit, 13...Selector, 15...
- Transmitter, 21... Connection control area detection circuit, 22...
・Reception latch circuit, 23... Empty channel detection circuit, 2
4... DA monitoring circuit, 25... reception control section, 26.
...Reception buffer circuits, two...Transmission control section, 30.
... Transmission buffer circuit, 31 ... Transmission latch circuit, 3
2... Vacant status flag generation circuit, 50... Synchronization area, 5]... Connection control area, 52... Line switching area, 5
3... Packet exchange area, 211... Comparison section, 21
2... End register, 213... Selector, 214
...Last slot number, 215...Test mode flag.

Claims (1)

[Claims] A control station and a plurality of stations are connected in a loop via a transmission path, and the control station receives a frame consisting of a connection control area and a data communication area divided into a plurality of slots. It circulates on the transmission path, transmits a connection control packet between the stations using the connection control area, and performs data communication between the stations using slots in the data communication area allocated by the connection control packet. In the loop type communication system, a test mode is provided to check whether the transmission path is operating normally, and in the test mode, communication is performed by forming the frame only with the connection control area. Transmission path test method for loop communication systems.