JPS62279751A - Data transmission system of loop type - Google Patents

Abstract

PURPOSE:To recognize the state of system in each transmission equipment so as to eliminate an exclusive supervisory unit by providing the function storing the addresses of all the stations on transmission lines, the insertion function of its own station address in a transmission frame and the alternation function of the address storage circuit in its own station, etc., in each transmission equipment. CONSTITUTION:The transmission format of a loop type data transmission system is constituted with a synchronizing bit S, a transmission destination address DA, a flag bit F and data I. The bit F of the format is set 1 in a transmission equipment, its own station address is inserted in an address part DA and the data I so as to transmit a frame to a transmission line. The frame is received in an interface circuit 1 and the bit F is detected in a flag detection circuit 3 through a synchronizing circuit 2. Next in terms of detecting the 1 of the bit F the head address of the data I is added to an address storage circuit 4 and its own station address is added to a vacant area after that time to be transmitted to the transmission line again, so that the addresses of the transmission equipments of all the stations can be added.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a loop data transmission system that connects to a data transmission device AT loop and transmits data. The present invention relates to an address management method for a data transmission device.

(Prior Art) Conventionally, in this type of loop data transmission system, addresses of data transmission devices on the loop have been managed by a specific transmission device such as a system monitoring device.

(Problems to be Solved by the Invention) In the conventional data transmission method described above, address management is performed only by a specific device that monitors the system on the loop, so each transmission device has no control over whether the data transmission destination exists on the system. It is unclear whether the other party is on the loop or not, and it is not known whether the other party is on the loop until the communication actually takes place. Therefore, there is a drawback that unnecessary traffic on the loop increases and transmission efficiency decreases.

(Means for Solving the Problems) The data transmission system of the present invention has a function in each data transmission device to store address information of transmission devices on a loop, and a function to distinguish it from normal data in a transmission frame. at least 1
A function to set a bit flag, set the flag to "1", and insert the own station address into the transmission frame, and a function to monitor frames with the flag rlJ on the transmission path and insert the own station address into the empty area of the frame with the flag "1". Each transmission device can check the system status by inserting an address and updating the address stored in the own station using the address information in the frame.
It is designed to perform data transmission.

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

FIG. 1 is a diagram showing a transmission format according to one embodiment of the present invention. In FIG. 1, S represents a synchronization bit, DA represents a destination address, F represents a flag bit, and Ifd data section. FIG. 2 is a block diagram showing the configuration of a transmission device applied to one embodiment of the present invention. 1,1' in Figure 2
2 is an interface circuit, 2 is a synchronization circuit, 3 is a flag detection circuit, 4 is an address storage circuit, and 5 is a frame generation circuit.

With such a configuration, for example, a newly installed transmission device on the loop can use the flag bit Flr of the transmission format shown in Figure 1.
IJ, insert the destination address DA and the own station address in the data section, and send the frame over the transmission path. In each transmission device on the transmission path, the empty frame is received by the interface circuit, passes through the synchronization circuit, and when the flag detection circuit detects that the flag F is "1", the frame is sent to the beginning of the data part in the transmission format. The address of the station is added to the address storage circuit 4vc, and the address of the own station is added to the subsequent empty area, and the address is sent to the transmission line again. The above steps are repeated and the address of the newly installed transmission device is added to all the transmission devices on the loop. Further, the newly installed station is notified of the addresses of all the stations in the frame as a frame addressed to the own station, and this address information is stored in the address storage circuit of the own station.

(Effects of the Invention) As explained above, the present invention stores the addresses of all stations on the transmission path within the transmission device, provides a flag bit in the transmission frame, and sets the flag bit to "1" to set the address of the own station. insert the frame and send it out, each station monitors the frame,
For frames with a flag bit of "1", the own station address is added to the empty area, and the address information stored in the own station is updated with the address information in the frame. Each station updates its own internal address information in response to changes, etc., and each transmission device can recognize the system status, resulting in efficient data transmission without sending frames with no other party. Furthermore, by inserting and storing the status information of each station in addition to the address, there is an effect that the status of the system can be monitored at any station without providing a dedicated monitoring station.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a frame format according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a transmission device to which the embodiment of the present invention is applied. S...Synchronization bit, DA...Destination address, F...Flag bit, Engineering...Data section, 1.1'...Interface circuit, 2...Synchronization circuit, 3... Flag detection circuit, 4... Address storage circuit, 5... Frame generation time g.

Claims (1)

[Claims] In a loop data transmission method in which data transmission devices are connected on a loop to transmit data, each transmission device has a function to store the addresses of all stations on the transmission path and at least a 1-bit flag in the transmission frame. There is a function that sets the flag to "1" and inserts the own station address into the transmission frame and sends it out, and a function that monitors the frame on the transmission path and sets the flag to "1".
1", it inserts its own station address into an empty area and sends it out. Furthermore, it has a function to update the address storage circuit in its own station with the address information in the frame, and each transmission device recognizes the system status. Loop data transmission method.