JP2713133B2 - Polling data collection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring station and a plurality of monitored stations connected by a bus network, polling from the monitoring station to the monitored station, and transmitting data from the monitored station via the bus network. The present invention relates to a polling data collection method for collecting data at a monitoring station.

[0002]

2. Description of the Related Art In a conventional general polling type data collection method, the same polling is performed for all monitored stations to be monitored by the monitoring station regardless of the state thereof. was there.

The time required for data collection for a maximum number of monitored stations set in advance as a system includes a data collection time for a normal (data communication enabled) monitored station and an abnormal or non-applicable (data communication disabled) time. ) Determined by the sum of the data collection time required for the monitored station. When there is no normal response from the monitored station to the polling from the monitoring station,
The monitoring station generally sends out a polling signal a plurality of times. Therefore, when the number of monitored stations that cannot communicate increases, the time required for data collection becomes extremely long.

[0004] In order to solve such a problem, various systems have been conventionally proposed. For example, JP-A-64-3
Japanese Patent No. 4036 discloses that the monitored station detects whether data communication is possible or data communication is not possible, and when data communication is not possible, polling information different from a normal polling signal is sent from the monitoring station, A response signal indicating whether or not a polling signal can be received is sent back to the monitored station that cannot communicate data, and a polling operation for data collection is performed in accordance with the response content. Discloses a monitoring control method for reducing the time required for data collection in a computer.

Japanese Patent Laid-Open Publication No. Hei 3-1088838 discloses a polling selector for improving data collection efficiency by polling all slave stations (monitored stations) that have requested transmission at once. A pointing system is disclosed. That is, in this system, the master station (monitoring station)
, A simultaneous polling frame for simultaneously polling all slave stations connected in a loop is transmitted. At this time, the slave station for which the transmission request exists inserts the address of its own node into its own time slot position in the simultaneous polling frame. On the other hand, a slave station having no transmission request at this point simply relays the simultaneous polling frame. In this way, when the simultaneous polling frame goes around all the slave stations and returns to the master station again, the master station collects the node addresses of the slave stations for which the transmission request exists, and sends the transmission request to all the slave stations. A polling signal including rank information is newly transmitted. When the slave station receives the polling signal, the slave station receives the information of the transmission request order included in the polling signal, and sends the information to the master station according to the transmission request order as soon as the carrier detection signal in the network is turned off. Transmit data sequentially.

Further, Japanese Patent Application Laid-Open No. 2-65337 discloses that
A channel access method is disclosed in which polling is not performed for a slave station (monitored station) having no communication request, thereby shortening the communication time. That is, in this system, the master station (monitoring station) is provided with a rewritable polling table and slave station number assigning means, while each slave station (monitored station) is provided with a slave number requesting means. When a communication request occurs in the slave station, the slave station number requesting means requests the master station to assign a slave station number, and in response to the request, the slave station number assigning means of the master station assigns the slave station number and polls the slave station number. Write to the table. Then, polling is performed only for the slave station corresponding to the written slave station number.

[0007]

However, in the supervisory control system disclosed in Japanese Patent Application Laid-Open No. 64-34036, a polling signal can be received at every polling cycle to all the unmonitored stations that cannot communicate. Since it is necessary to return a response signal indicating whether or not the communication is in a normal state, if the number of unmonitored monitored stations increases, the time required for data collection becomes longer.

In the polling selecting system disclosed in Japanese Patent Application Laid-Open No. 3-1088838, a polling frame is sent to all monitored stations at the same time, and after the addresses of the monitored stations having transmission requests are collected, Since polling for data collection is performed, there is a disadvantage in that extra time is required to collect addresses.

Further, in the channel access system disclosed in Japanese Patent Application Laid-Open No. 2-65337, a slave station (monitored station)
Requires a master station to assign a slave station number, and the master station needs to assign a slave station number in response to the request, which disadvantageously complicates the processing.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to efficiently collect data of a plurality of monitored stations in a monitoring station, to shorten the time required for the collection, and to simplify the processing. Another object of the present invention is to provide a simple polling data collection method.

[0011]

In order to achieve the above object, according to the present invention, a monitoring station and a plurality of monitored stations are connected by a bus network, and the monitoring station polls the monitored station to monitor the monitored station. In a polling-type data collection method in which data from a station is collected by a monitoring station via a bus network, the monitoring station is provided with the following means. A rewritable first storage table for storing identifiers of monitored stations capable of data communication as a first group. A rewritable second storage table for storing, as a second group, identifiers of monitored stations that cannot perform data communication. With reference to the identifiers stored in the first and second storage tables, in one polling sequence,
Data request means for sending data requests to all monitored stations belonging to the first group and one monitored station sequentially selected from the monitored stations in the second group. Based on the identifiers stored in the first and second storage tables, the data requesting means determines the order of monitored stations to which a data request should be sent for each polling sequence, and selects one of the stations selected from the second group. A data request ranking determining means that sets the rank of the monitored stations next to the last monitored station of the first group. Reception determining means for determining whether data has been normally received from the monitored station that has transmitted the data request. Based on the determination result, for the monitored station of the first group that could not be normally received, the identifier is rewritten into the second storage table, and the monitored station of the second group is normally operated. For the monitored station that could be received,
Rewriting means for rewriting the identifier in the first storage table;

[0012]

According to the present invention, among the plurality of monitored stations, the monitored stations capable of performing normal data communication are those that cannot perform data communication because they are not connected to the first group or the bus network. The disabled monitored station is classified into the second group. In one polling sequence, the monitoring station first collects data by sequentially making data requests to all monitored stations belonging to the first group,
Subsequently, a data request is made to one of the monitored stations belonging to the second group in the first order. If data can be normally received from the one monitored station, the monitored station is moved to the first group and data to be collected is collected. However, if it cannot be received normally, it is left in the second group. Then, in the next polling sequence, the data request is sequentially made again to all the monitored stations in the first group, and then the data request is made to the next monitored one station in the second group. . That is,
For the monitored station of the second group that cannot communicate, a data request is made for only one monitored station per polling sequence to determine whether normal data communication can be performed. The stations are shifted sequentially in each polling sequence. On the other hand, when a data request is made to the monitored station in the first group, but data cannot be normally received from a monitored station in the first group, the monitored station is moved to the second group, Make a data request to the next monitored station in the first group.

Accordingly, the time required for one polling sequence is determined by the time required for data request and the time required for data collection for all monitored stations in the communicable first group, and the time required for data collection. The time required to add the data request time to one monitored station in the second group is sufficient, and the waste of making a data request to another monitored station in the uncommunicable second group is eliminated. Can be. Also, for the monitored stations in the second group, only one monitored station is requested for data in one polling sequence, but the monitored stations requesting the data are sequentially shifted, so that communication is possible. Not only can all the monitored stations of the first group collect data, but if the monitored stations of the second group can also perform normal data communication, the order of polling for the monitored stations will start. Data can be gathered at the time.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a communication system to which the data collection method according to the present invention is applied. In this communication system, one monitoring station (node 0) 2 and N monitored stations (node 1 to node N) 3 are connected on a bus-like network 1, and these monitoring stations 2 and N monitored stations are connected. The monitoring station 3 is assigned an individual address (identifier).

As shown in FIG. 1, the monitoring station 2 includes first and second storage tables 4 and 5, a rewriting means 6, a data request order determining means 7, a data request means 8, a reception determining means 9, Is provided.

The first storage table 4 stores the identifiers of the monitored stations 3 capable of data communication as a first group A, and the second storage table 5 stores the identifiers of the monitored stations 3 not capable of data communication. Is stored as the second group B. These storage tables 4 and 5 are:
As shown in FIG. 3, the identifiers are stored in node order.

The data request rank determining means 7 determines the data request rank for all the monitored stations 3 of the first group A based on the identifier stored in the first storage table 4, and stores the data request rank in the second storage table. On the basis of the identifiers stored in the table 5, the data request rankings for sequentially selecting one of the monitored stations 3 of the second group B one by one and making a data request are determined. In this case, the data request for one selected monitored station 3 in the second group is determined to be after the last monitored station in the first group. The data request unit 8 sends out data requests to the monitored station 3 in the order according to the data request order determined by the data request order determination unit 7.

The reception judging means 9 judges whether or not the data from the monitored station 3 which has transmitted the data request has been normally received by the monitoring station 2. The rewriting means 6 performs the first and second storage tables 4 and 5 based on the judgment result of the reception judgment means 9.
Rewrite the identifier in.

Next, the data collection operation performed by the monitoring station 2 will be described with reference to FIGS. FIG.
First, the monitoring station 2 sets the first node in the second group B to the processing node b by the data request rank determining means 7 (step S1), and then sends it to all the monitored stations in the first group A. Then, a data request is made to collect data from the data request (step S2).

The data collection processing in step S2 is shown as a subroutine in FIG. In the figure, monitoring station 2
Sets the first-ranked node in the first group A to the processing node a by the data request rank determination means 7 (step S11), and then requests the data from the processing node a by the data request means 8. (Step S12). Then, the reception judging means 9 judges whether or not the data has been normally received from the processing node a (step S1).
3) If the reception was successful, proceed to step S15,
The data requesting node determining unit 7 determines whether the processing node a is the last node in the first group A or not. If it is not the last node, the process proceeds to the next step S16, where the next-ranked node of the first group A is processed data a by the data request rank determining means 7, and returns to step S12 to repeat the same operation.

On the other hand, if it is determined in step 13 in FIG. 7 that the reception has failed and the timeout has occurred, the process proceeds to step S14, where the node a being processed is deleted from the first group A and added to the second group B. . That is, the identifier between the first storage table 4 and the second storage table 5 is rewritten by the rewriting means 6. 4 and 5 are schematic diagrams of the rewriting operation. When the identifier of the node a being processed is, for example, n, FIG. 4 shows that the identifier n is deleted and the storage corresponding portion becomes empty, and FIG. 5 shows that the identifier n is stored in the empty storage portion.

When the data collection from the monitored station 3 of the last rank of the first group A is completed, the processing for the monitored station 3 of the group B is performed next. That is, step S in FIG.
The process proceeds from step 2 to step S3, and the data requesting unit 8 requests data for the data-in-process b. Then, the reception determining means 9 determines whether or not the data has been normally received from the node b during the processing (step S13).
The data request ranking determining means 7 determines whether the processing node b is the last node in the second group B or not. If it is not the last node, the next step S7
The data request rank determining means 7 determines the next-ranked node of the second group B as the data-in-process b, and returns to step S2 to perform the processing shown in FIG. 7 again.

On the other hand, if it is determined in step 4 of FIG. 6 that the reception was successful, the process proceeds to step S5, where the rewriting means 6 rewrites the identifier between the second storage table 5 and the first storage table 4. Then, the in-process node b is deleted from the second group B and added to the first group A.

FIG. 8 is a timing chart showing a specific example of the processing shown in FIGS. In this case, one monitored station 2 monitors six monitored stations 3, and these six monitored stations 3 are monitored.
One node (monitored station) has an identifier (address) of 1
FIG. 8 will be described assuming that the numerical values of 6 are respectively assigned.

First, the first group A includes nodes 1 and 2
And the second group B has nodes 3, 4, 5, and
6 belong to the first polling sequence Sp1, the data request to the node 1 of the first group A and the data collection therefrom, the data request to the node 2 and the data collection therefrom are sequentially and normally performed. After that, when a data request is made to the first node 3 of the second group B, it indicates that data cannot be normally received from this node 3 and a timeout has occurred.

In the second polling sequence Sp2, the data request to the node 1 of the first group A and the data collection therefrom, the data request to the node 2 and the data collection therefrom are sequentially and normally performed. When the data is requested from the next node 4, the data has been normally collected from this node 4, indicating that the node 4 has been moved from the second group B to the first group A.

In the third polling sequence Sp3, in the first group A, a data request to the node 1 and data collection therefrom, a data request to the node 2 and data collection therefrom, and as described above, the first group A
After the data request for the node 4 moved to the group 4 and the data collection from the node 4 were sequentially and normally performed, the data request was made to the node 5 of the second group B.
Indicates that timeout has occurred because data could not be received normally from.

In the fourth polling sequence Sp4, a data request to the node 1 of the first group A and data collection therefrom, a data request to the node 2 and data collection therefrom, a data request to the node 4 and data collection therefrom are performed. After the normal operation in sequence, the second
When a data request is made to the last node 6 of the group B, it indicates that data cannot be normally received from this node 6 and a timeout has occurred.

In the fifth polling sequence Sp5, a data request to the node 1 of the first group A and data collection therefrom, a data request to the node 2 and data collection therefrom, a data request to the node 4 and data collection therefrom are performed. After the normal operation in sequence, the second
When a data request is again made to the first node 3 of the group B, it indicates that data cannot be normally received from this node 3 and a timeout has occurred.

In the sixth polling sequence Sp6, the data request to the node 1 of the first group A and the data collection therefrom were normally performed, but the data could not be normally received from the node 2 and a timeout occurred. From the first group A to the second group B
Then, the data request to the node 4 and the data collection therefrom are normally performed. After that, the data request is made to the node 5 of the second group B, and the data can be normally received from the node 5. Indicates that a timeout has occurred.

In the seventh polling sequence Sp7, the data request to the node 1 of the first group A and the data collection therefrom, the data request to the node 4 and the data collection therefrom are sequentially and normally performed, and then the second group B This indicates that when a data request was made to the last node 6, data could not be normally received from this node 6 and a timeout occurred.

[0033]

As apparent from the above description, the present invention has the following effects. Among the plurality of monitored stations, the monitored stations capable of performing normal data communication are the first group, and the non-communicable monitored stations that cannot perform the data communication because they are not connected to the bus network are the second group. After classifying the data into groups and collecting data by sequentially making data requests to all the monitored stations belonging to the first group for each polling sequence, the monitored stations belonging to the second group are then Of 1
Since a data request is made to one monitored station and the monitored stations in the second group that request data are sequentially shifted in each polling sequence, the time required for data collection can be reduced. For all the monitored stations in the first group with which communication is possible, all data can be collected regardless of the data length, and for the monitored stations in the second group, one data is collected per polling sequence. Although the data request is made only to the monitored station, the monitored stations requesting the data are sequentially shifted. If the monitored stations in the second group can also perform data communication normally, polling of the monitored station is performed. When the turn comes, you can collect data from now on. The processing is simple as a whole, and data of a plurality of monitored stations can be efficiently collected at the monitoring station.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a monitoring station in a polling data collection method of the present invention.

FIG. 2 is a block diagram of a communication system to which the data collection method of the present invention is applied.

FIG. 3 is a schematic diagram illustrating a storage mode of an identifier in a storage table in FIG. 1;

FIG. 4 is a schematic diagram showing how to delete an identifier in the storage table.

FIG. 5 is a schematic diagram showing how to add an identifier in the storage table.

FIG. 6 is a flowchart showing a flow of a data collection operation by the monitoring station.

7 is a flowchart specifically showing a first group data collection process shown in FIG. 6 as a subroutine.

FIG. 8 is a timing chart illustrating a specific example of the processing shown in FIGS. 6 and 7;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bus-like network 2 monitoring station 3 monitored station 4 first storage table 5 second storage table 6 rewriting means 7 data request order determination means 8 data request means 9 reception determination means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H04Q 9/00 311 G06F 15/74 320B

Claims (1)

(57) [Claims] A monitoring station and a plurality of monitored stations are connected by a bus-like network, and polling is performed by the monitoring station to the monitored station and data from the monitored station is collected by the monitoring station via the bus-like network. In the formula data collection method, a rewritable first storage table for storing an identifier of a monitored station capable of data communication as a first group in the monitoring station, and an identifier of a monitored station unable to communicate data in a first group. With reference to the rewritable second storage table for storing as two groups, and the identifiers stored in the first and second storage tables, all the data belonging to the first group are referred to in one polling sequence. Data request means for sending a data request to a monitored station and one monitored station sequentially selected from the monitored stations in the second group; Based on the identifiers stored in the first and second storage tables, the data requesting means determines the order of monitored stations to which a data request should be sent for each polling sequence, and selects from the second group. The order of one monitored station is determined by the data request ranking determining means next to the last monitored station in the first group, and whether or not data has been normally received from the monitored station that has sent the data request. The receiving determination means, and, based on the determination result, for the monitored station of the first group that could not be received normally, the identifier is rewritten into the second storage table, and the monitored station of the second group is rewritten. Rewriting means for rewriting an identifier of a monitored station that has been normally received by the monitoring station into a first storage table; and a polling data collection method.