JPH03126344A - Data branch direction switching system - Google Patents

Abstract

PURPOSE:To attain effective utilization of a data processing unit of a master station by providing a switch switching a master station sending a digital signal inserted and branched to a slave station. CONSTITUTION:Switches 7-9 sending and receiving a branch insertion signal with a master station 28(34) in a specific direction having a control right are provided on equipments of slave stations 29-33 in a data branch direction switching system in which plural slave stations 29-33 are connected in tandem between at least two master stations 28, 34 and branch and insertion connection of a digital signal is implemented between the master stations 28, 34 and between the master stations 28, 34 and the slave stations 29-33. When the master station 28 transfers the control right to the other master station 34, the slave stations 29-35 receive a command signal of control right shift to change over the switches 7-9 thereby sending and receiving the branch insertion signal to/ from the other master station 34. Thus, the effective use of the data processing unit is attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a data branching direction switching system, and particularly to a data branching direction switching system.
A master station that specifies the information of the slave stations using a digital signal in a configuration in which a master station device of a station or higher and a plurality of slave station devices that can be interposed between the master station are connected in tandem via a four-wire transmission line. This invention relates to a data branching direction switching method for transmitting data.

[Conventional technology]

Conventionally, this type of data branching direction switching system, as shown in the general line configuration diagram in FIG. The slave stations 29 to 33 connected in tandem were capable of transmitting and receiving data information to and from the master stations 28 and 34 at both ends, respectively. The circuit for the slave stations 29 to 33 to insert and branch digital transmission signals to the four-wire transmission line 27 is configured as shown in the circuit diagram of FIG. 13 and the insertion signal 2OA sent from the branch unit 21 and the communication interface 20 of the slave station, and the resultant result is sent out as the transmission signal 18. Further, the logical sum circuit 16 performs a logical sum on the received signal 19 and the insertion signal 13A, and sends the result as a transmitted signal 14. On the other hand, the circuit configuration was such that the received signal 13 and the received signal 19 are branched as a branch signal 20B of this slave station.

[Problem to be solved by the invention]

In the conventional data branching method to the master station described above, for example,
When the master station 28 and slave station 31 transmit at the same time,
The slave station 32, the slave station 33, and the slave station 34 are the master station 28 and the slave station 3.
The signals of the logical sum of the two transmitted signals are both received, and an abnormality in the received signal is detected. Furthermore, even if the transmission is not simultaneous, if the master station 28 has control authority, the transmission from the slave station 31 only needs to be received by the master station 28, but if the slave station 29°30.32.33 and the master The problem is that the data is also received by the station 34, causing it to perform unnecessary processing, thereby hindering the effective use of the data processing device of the master station 34.

[Means for Solving the Problems] The data branching direction switching method of the present invention has a plurality of slave stations connected in tandem between a master station consisting of at least two stations,
In the data branching direction switching method that performs a connection operation for adding/dropping digital signals between the master stations and between the master station and the slave station, the device of each slave station connects the master station and branch in a specific direction over which it has control authority. The slave station has a switch for sending and receiving an insertion signal, and when the master station transfers the control right to another master station, the slave station receives the control right transfer instruction signal and switches the switch to transfer the control right to the other master station. It sends and receives add/drop signals to and from stations.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and shows a circuit in which the embodiment of the present invention is applied to slave stations 29 to 33 shown in FIG. Now, the received signal 1 on the 4-wire transmission line 27
When there is a master station with control rights in the direction of the transmission signal 2,
By setting the switches 7, 8, and 9 to the terminal 9A side, the received signal 1 is outputted as the transmitted signal 5 via the OR circuit 3, and is also outputted as the branched signal 10B through the switch 9 to the communication interface 10. is input to. The received signal 6 passes through the OR circuit 4 and is output as the transmitted signal 2. On the other hand, the insertion signal 10A from the communication interface 10 is output as the transmission signal 2 via the terminal 7A of the switch 7 and the OR circuit 4. When a master station with control authority (master station 28 in Fig. 2) transfers control authority to another master station, it sends a data branching direction switching request command to each slave station. When the main control unit 11 determines that the command to be directed to the local station is given, the slave station shown in FIG. Connect switch 8 and switch 9 to terminal 7, respectively.
Switch to B, 8B, 9B. After the switching is completed, the control right of the master station has been transferred to the master station 34 shown in FIG. j! It is outputted as the transmission signal 2 through time t4, and is also inputted into the communication interface 10 through the terminal 9B of the switch 9. Note that the received signal l is
It is relayed as a transmission signal 5 via an OR circuit 3. On the other hand, the insertion signal 10A of the communication interface 10 passes through the terminal 8B of the switch 8, passes through the OR circuit 3, and becomes the transmission signal 5.
The data transmission direction is switched to the master station 34.

〔Effect of the invention〕

As explained above, the present invention provides a switch that can switch the master station that transmits digital signals inserted and dropped from the slave station under the control of the main control unit of the slave station, thereby preventing signal abnormalities caused by data overlap. This has the advantage that the data processing device of the main control section can be used more effectively than in the conventional example in which data is transmitted in the direction of the parent station.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a general line configuration diagram, and FIG. 3 is a circuit diagram showing a conventional data branching method for a slave station. 1.6... Received signal, 2,5... Transmitted signal, 3゜4
．． 15, 16.17...OR circuit, 7,8.9...
・Switch, 10...Communication interface, 10A
... Insertion signal, 1 B... Branch signal, 1... Main control unit, 2... Control signal, 28°34... Master station, 29-3... Slave station.

Claims (1)

[Claims] A data branching direction switching method in which a plurality of slave stations are connected in tandem between at least two master stations, and connection operations for adding and dropping digital signals are performed between the master stations and between the master station and the slave stations. In the device, each of the slave stations has a switch for exchanging drop-and-add signals with a master station in a specific direction in which it has control authority, and when the master station transfers control authority to another master station, the slave station 1. A data branching direction switching system, characterized in that the base station receives a control right transfer instruction signal, switches the switch, and sends and receives drop-and-add signals to and from the other master station.