JPS6331982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data collection system in which a master station collects data from one or more slave stations, and particularly to a data collection system that aims to shorten data collection time.

Generally, when one master station collects data from one or more slave stations, the master station issues data request commands to each slave station in sequence and collects the data sent from each slave station. ing. In this case, the slave station transmits all data in response to the master station's request, even if its own data is no different from the previously transmitted data.
On the other hand, the master station collects all data from the slave stations.

However, it is pointless for the master station to collect data that has not changed at all from the slave stations; if there is only one slave station, there is no need for the master station, and as the number of slave stations increases, data collection will be necessary. It also has the disadvantage of being extremely time consuming.

The present invention has been made in view of the above-mentioned circumstances, and is such that the master station collects data from the slave station only when there is a change in status, and the slave station collects data from the slave station only when there is a change in status among a plurality of input data. The purpose is to provide a data collection system that can be edited and sent to improve the efficiency of data collection.

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows 1 in the system of the present invention.
1 is a diagram showing a schematic configuration of a slave station, in which a master station (not shown) is configured to exchange data with one or more slave stations via a transmission line or wirelessly. The configuration of the slave station shown in FIG. 1 will be specifically explained below. In the figure, 11 indicates a plurality of signal inputs X ₁ ,
_{X 2} , .
This is a signal input control circuit that stores signals in bits corresponding to X ₂ , . Reference numeral 12 denotes a state change detection control circuit which constantly monitors the input data A of the signal input control circuit 11 and stores data indicating whether a state change exists or not in a bit corresponding to the signal input. B indicates state change data output from the state change detection control circuit 12. 13 is state change data B or input data A depending on the content of the received data from the master station (not shown).
This is a transmission control circuit that takes in data and outputs transmission data C. Reference numeral 14 denotes a transmission transmission circuit that takes in transmission data C and sends transmission transmission data D to the master station through a transmission line 15. 16 is a receiving circuit that receives the data transmission command E sent from the master station through the transmission path 15; 17 is a receiving circuit that receives the signal F obtained by the receiving circuit 16 and determines whether it is the state change data request command G or the input data request command H; The determination is made and the content of the determination is sent to the transmission control circuit 13.
This is a reception control circuit that supplies signals to the

Next, the operation of the data collection system as described above will be explained. Normally, in the case of a slave station, the signal input control circuit 11 takes in the signal inputs X ₁ , X ₂ , ... and creates digitally encoded input data A, which corresponds to _the signal inputs X ₁ , It is stored in bits and sent to the state change detection control circuit 12. This state change detection control circuit 12 constantly monitors the input data A, determines whether there is a state change by comparing it with the previous data, and stores it in the bits corresponding to the respective signal inputs X ₁ , X ₂ , . . . Outputs state change data B for each bit in parallel or serially. However, this state change data B is the signal input X ₁ ,
If X ₂ , .

When a data request command E including a state change data request command G is sent from the master station in the above state, this is received by the reception circuit 16 of the slave station and converted into a reception command F. The reception control circuit 17 receives this reception command F, determines from the content of the data request command E that it is a state change data request command G, and supplies it to the transmission control circuit 13. In response to the state change data request command G, the transmission control circuit 13 takes in state change data B with and without state changes corresponding to the plurality of signal inputs X ₁ , X ₂ , . . . in parallel or serially, and generates synchronous data. It is converted into transmission data C containing the data and sent to the transmission transmission circuit 14.

In this case, if there is no state change in the data, this can be explained using time charts such as those shown in FIGS. 2 and 3. That is, when the transmission control circuit 13 receives a state change data request command G as shown in _FIG .
State change data _B1 with no state change for each _of X ₂ , and transmits it to the master station.

When there is a state change in the data, state change data _B2 indicating a state change is attached to the synchronized data S based on the state change data request command G and output as transmission data C, as shown in FIG. In this case, the master station issues an input data request command H as shown in FIG. 3c, and in response, the slave station transmits the original input data as shown in FIG. 3d.

The above points will be explained in more detail. now,
If _{the status change data B for each signal input X 1 ,} Perform data collection.

If there is a state change in any one or two or more of the state change data B ₂ corresponding to the plurality of signal inputs X ₁ , X ₂ , ..., the master station determines that there is a change, but the state If the number of change data _B2 is small and it is considered that there is no need to collect data, the process moves to the next slave station and executes it.

When determining that data collection is necessary, the master station outputs a data request command E including an input data request command H. This data request command E is then received by the receiving circuit 16 and transmitted as a receiving command F to the receiving control circuit 17. The reception control circuit 17 determines from the content of the reception command F that it is an input data request command H as shown in FIG. 3c, and supplies it to the transmission control circuit 13. When this transmission control circuit 13 receives the input data request command H, it takes in and organizes only the input data A that has changed from the input data A stored in advance in the signal input control circuit ₁₁ based on the state change data B2. It is transmitted to the master station. Figure 3d
indicates the contents of data organized by the transmission control circuit 13. For example, if there is a state change except for signal input _{X 1} , input data A ₂ , A ₃ , etc. excluding signal input
Transmit as.

The master station receives the data D from the slave station and rewrites it for each signal input while checking the previously stored input items. After this rewriting is completed, data collection for the next slave station is executed. Therefore, since the master station collects only the data of slave stations whose status has changed, it is possible to shorten the time for data collection.

As detailed above, according to the present invention, in response to a data request from the master station, the slave station sends data indicating whether there is a status change, and based on this, the input data is edited from the slave station only when there is a status change. Even if the number of slave stations increases, the data collection time can be significantly reduced. Therefore, it is very effective, especially for systems with a large number of slave stations and where input data does not change very frequently.

[Brief explanation of the drawing]

Fig. 1 is a configuration example diagram in which the data collection method according to the present invention is applied to a slave station, Fig. 2 is a timing chart when there is no state change, and Fig. 3 is a timing chart when there is a state change. be. 11...Signal input control circuit, 12...State change detection control circuit, 13...Transmission control circuit, 14...
Transmission transmission circuit, 16...Reception circuit, 17...Reception control circuit, _X1 , _X2 ,...Signal input, A...Input data, B...State change data, G...State change data request command, H...Input data request command.

Claims (1)

[Claims] 1. In a system in which a master station sequentially selects one or more slave stations to collect input data, the slave station converts a plurality of signal inputs into digitally encoded input data. The signal input control circuit to be stored monitors each input data stored in this signal input control circuit, and determines whether or not there is a state change in the signal based on the relationship with the input data when the previous plurality of signal inputs were digitally encoded. A state change detection control circuit stores data in a bit corresponding to the input, and determines the presence or absence of a state change from the output data of the state change detection control circuit in response to a state change data request command from the master station. data transmitting means that transmits data to that effect, and then, upon receiving an input data request command from the master station, edits only the input data with a state change stored in the signal input control circuit and transmits the edited data to the master station; A data collection system, characterized in that the master station collects edit input data with a state change only when there is a state change.