JPS59212050A - Data collection system - Google Patents

Abstract

PURPOSE:To improve transmission efficiency and to detect easily a faulted point by transmitting data on each transmitting terminal station additionally to the tail of received data when the station receives the data from an upstream-side terminal station, and transmitting the data independently when no data is received for a specific time. CONSTITUTION:Data transmitting terminal stations 21-2m transmit data to a data collecting station 1. At this time, a terminal station 2n transmits data periodically and a low-order station 2n-1 transmits its own data additionally to the tail of the received data. Similarly, the lowest-order station 21 also transmits its data. Each terminal station transmits its own data independently unless data is received from the high-order station for the specific time. For the purpose, the data is analyzed to detect a faulty station.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data acquisition system, and particularly relates to a data acquisition system suitable for a case where a plurality of data transmission terminal stations are connected in series or in a loop to a data acquisition station. .

One of the conventionally known data collection methods is a polling method. To briefly explain this method, first, the data collection station regularly solicits each data transmission terminal station, one station at a time, in order to send a message or request. The data transmitting end station that receives the invitation obtains the right to transmit the information message and is enabled to perform the information transfer.

However, the above method has the following problems.

In other words, in a system where there are many data transmitting terminal stations that transmit data frequently, the overhead for actual data transfer is large, so the effective transmission efficiency tends to be poor and the transmission waiting time tends to be long. .

Also, as a modification of the polling method, GA (G.

Ahead) There is a polling method, but in this method, a polling signal called a GA multiplication signal is sequentially sent to each terminal station without inviting each data transmission terminal station to send data. This applies when the network is in loop form.

In this case, if each terminal station loses the GA signal, it will re-add the GA signal after the data it wants to send, and if there is no data to send, it will send the GA signal Send it to that network. As is clear from this, all the data transmitting terminal stations connected to the GA multiplication signal loop are polled during one round, and the transmission efficiency is higher than that of the above-mentioned polling method. However, in a loop system, if some abnormality occurs in the system,
This causes a problem in that the data is fragmented on the spot, and it takes time and effort to detect the point of failure.

As a countermeasure, the system may be made into a dual system, or a loop/
Although it is possible to deal with this problem by providing a quick check function or a quick write function, this would result in an extremely large scale of software and hardware, leading to high costs. This is a major obstacle, especially when applied to relatively simple systems such as data collection systems.

The present invention has been made in view of the above, and aims to improve transmission efficiency, facilitate the detection of failure points, and improve the data format and circuit configuration of each data transmission terminal station. The objective is to provide a data collection system that can simplify the process.

The present invention is characterized in that, when each data transmission terminal station receives data from an upstream data transmission terminal station, the station adds its own data to the received data and transmits the data, and the upstream data transmission terminal station The station is provided with means for autonomously transmitting its own data if the station does not receive data within a predetermined time.

The present invention will be explained in detail below using examples shown in the drawings.

The figure is a configuration diagram showing an embodiment of the data collection system of the present invention. In the figure, 1 is the data collection station, 21 +
22 + and +2n-1n 21 are data transmission terminals, 3 is a transmission line, and as shown in the figure, each terminal station 21 to 2 is connected in series to the data collection station l, and the data collection station 1 is Data groups sent out from each data transmission terminal station 21 to 2n are collectively processed.

By the way, although illustration of a specific circuit configuration is omitted, each of the terminal stations 21 to 2n is configured so that data transmission from each of the terminal stations 21 to 2n is performed in the following manner. That is, the terminal station 2n located farthest from the data collection station 1 is configured to transmit data at a constant cycle. The next terminal station 2n+ waits for the data to arrive from the most upstream terminal station 2n, and as soon as the data arrives and receives it, it adds its own data after that data and sends it to the transmission line 2n.
It is configured to be sent to However, be sure to add a specific bit/ξ turn to the end of your own data to clarify the end position of the data. Next terminal 2
When the data group from n-2 to terminal station 21 is received from the terminal station one level upstream, it detects the hit/ξ turn, and if it detects a bit/ξ turn, it erases that bit/ξ turn. , the own station data are added, and finally the above bits and ξ turns are added again and sent to the transmission path 3.

When the most downstream terminal station 2I finishes transmitting data,
The data group is taken into the data collection station 1 and processed all at once.

Furthermore, when each terminal station 21 to 2n-1 does not receive data from the upstream terminal station for a predetermined period of time, it automatically becomes the most upstream station and starts transmitting data. It is composed of: Therefore, even if data is interrupted at a certain point due to a failure of the upstream terminal station or disconnection of the transmission line 3, data can be transmitted from the terminal station downstream of the failure point. . Moreover, at the same time, the data collection station 1 can know the location where the failure has occurred. For example, in the figure, if terminal station 2n-2 does not receive data from terminal station 2n-1 within a predetermined time, terminal station 2n-2
-2 starts transmitting data by itself. Therefore, the data collection station 1 is the terminal station 21 to 2n downstream of the terminal station 2n-2.
-2 can receive the data, and there is a problem in the terminal station 2n-1 on the one-stream side from the terminal station 2n-2 or in the transmission line 3 between the terminal station 2n-2 and the terminal station 2n-1. It is possible to recognize that a problem has occurred, and to detect the point of failure.

As described above, according to the embodiments of the present invention, 1. Even if a failure occurs at any point, it is possible to transmit data from a data transmission terminal station downstream from that point.

2. From the data received at data collection station 1, the failure point 6
− can be detected.

3. All terminal stations can be configured with the same nodeware.

4. If the data processing at the terminal station is simple, the hardware can be simplified and the circuit configuration can be simplified.

Note that the present invention can also be applied to a loop-type system.

In this case, as in the case of the above embodiment, the data collection station cannot immediately recognize the point of failure, and by performing a loop and check between the data transmitting terminals before and after the point of failure, data other than the point of failure can be returned normally. can be imported.

As explained above, according to the present invention, transmission efficiency can be improved, failure points can be easily detected, and the data format and circuit configuration of each data transmission terminal station can be simplified. be.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the data collection system of the present invention. 1...Data collection station, 21-2n...Data transmission terminal station, 3...Transmission path. 2, 2□

Claims (1)

[Claims] 1. In a data collection system in which a plurality of data transmission terminal stations are connected in series or in a loop to two data collection stations, each data transmission terminal station receives data from an upstream data transmission terminal station. Means for transmitting the station's own data after the received data, and voluntarily transmitting the station's own data when data is not received from the upstream data transmitting terminal within a predetermined time. A data collection system characterized by comprising means.