JPH06276203A - Polling type data collection system - Google Patents

Abstract

PURPOSE:To provide a polling type data collection system which can collect the data on plural monitored stations with high efficiency at a monitor station, can shorten the data collecting time, and also can simplify the data collecting way. CONSTITUTION:The identifiers of the monitored stations which are capable of data communication are defined as a 1st group, and the identifiers of the monitored stations which are incapable of data communication are defined as a 2nd group. These two groups are stored in the 1st and 2nd storage tables 4 and 5 respectively. A data request order deciding means 7 decides the order or all monitored stations of the 1st group that should transmit the data requests through a data request means 8 and one of monitored stations of the 2nd group based on those stored identifiers. Then a reception deciding means 9 decides whether the data are normally received or not by a monitor station from the monitored stations that had the data requests. A rewriter means 6 rewrites the identifiers stored in both tables 4 and 5 based on the deciding result of the means 9.

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-like network, polling the monitoring station to the monitored station and transmitting data from the monitored station via the bus-like network. The present invention relates to a polling-type data collection method that is collected by a monitoring station.

[0002]

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

The time required for data collection for the maximum number of monitored stations preset by the system is the data collection time required for normal (data communication possible) monitored stations and the abnormal or non-applicable (data communication impossible) ) Determined by the total of the data collection time required for the monitored station. If there is no normal response from the monitored station to the polling from the monitoring station,
The monitoring station generally repeatedly sends the polling signal a plurality of times. Therefore, as the number of monitored stations that cannot communicate increases, the time required to collect data becomes extremely long.

In order to solve such a problem, various methods have been conventionally proposed. For example, JP-A-64-3
No. 4036 discloses that a monitored station detects whether data communication is possible or not, and when data communication is impossible, the monitoring station sends polling information different from a normal polling signal, By sending a response signal indicating whether or not the polling signal can be received to the monitored station that cannot communicate data, and performing a polling operation for data collection according to the response content, the monitoring station Discloses a supervisory control method that shortens the time required to collect data.

Further, Japanese Patent Laid-Open No. 3-108838 discloses a polling selection in which data collection efficiency is improved by collectively polling all slave stations (monitored stations) that have a transmission request. An operating system is disclosed. That is, in this system, the parent station (monitoring station)
Sends a polling frame for polling all the slave stations connected in a loop at once. At this point, the slave station that has a transmission request inserts the address of its own node at the time slot position of its own station in the simultaneous polling frame. On the other hand, the slave station which has 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, the master station collects the node addresses of the slave stations for which there is a transmission request, and sends the transmission request to all the slave stations. A polling signal including ranking information is newly transmitted. When the slave station receives this polling signal, the received slave station stores the information of the transmission request order included in the polling signal, and as soon as the carrier detection signal in the network is turned off, it sends to the master station according to the transmission request order. Send data sequentially.

Further, in Japanese Patent Laid-Open No. 2-65337,
A channel access method has been disclosed in which communication time is shortened by not polling a slave station (monitored station) that does not have a communication request. 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 slave station number requesting means. When a communication request is generated in a slave station, the slave station number requesting means requests the master station to allocate a slave station number, and the slave station number allocating means of the master station allocates the slave station number in response to the request, and polls the slave station number. Write on the table. Then, only the slave stations corresponding to the written slave station number are polled.

[0007]

However, in the supervisory control method disclosed in Japanese Patent Laid-Open No. 64-34036, it is possible to receive polling signals for all monitored stations that cannot communicate with each polling cycle. Since it is necessary to send back a response signal indicating whether or not it is in such a state, there is a disadvantage that the time required for data collection becomes longer as the number of monitored stations that cannot communicate increases.

In the polling / selecting system disclosed in Japanese Patent Laid-Open No. 3-108838, a polling frame is sent to all monitored stations, and after collecting the addresses of the monitored stations that are requested to transmit, Since polling is performed for data collection, there is a drawback that it takes extra time to collect addresses.

Further, in the channel access system disclosed in Japanese Patent Laid-Open No. 2-65337, a slave station (monitored station)
Requires the master station to allocate the slave station number, and the master station needs to allocate the slave station number in response to the request, which is a drawback that the process becomes complicated.

In view of the above-mentioned conventional drawbacks, an object of the present invention is that the data of a plurality of monitored stations can be efficiently collected at the monitoring station, the time required for the collection can be shortened, and the processing is simple. To provide a simple polling data collection method.

[0011]

In order to achieve such an object, according to the present invention, a monitoring station and a plurality of monitored stations are connected by a bus-shaped network, and the monitored station polls the monitored station for monitoring. A polling-type data collection system in which data from stations is collected by a monitoring station via a bus network is characterized in that the monitoring station is provided with the following means. A rewritable first storage table for storing an identifier of a monitored station capable of data communication as a first group. A rewritable second storage table for storing, as a second group, the identifiers of monitored stations that cannot perform data communication. With reference to the identifiers stored in the first and second storage tables, all monitored stations belonging to the first group and one monitored station sequentially selected from the monitored stations of the second group Data request means for sending a data request to the. Reception determination means for determining whether or not data has been normally received from the monitored station that has transmitted the data request. Rewriting means for rewriting the identifiers in the first and second storage tables based on the determination result.

Further, based on the identifiers stored in the first and second storage tables, the data request order determination for determining the order of the plurality of monitored stations to which the data request should be sent by the data request means. It is good to have means.

[0013]

According to the present invention, among the plurality of monitored stations, the monitored station capable of performing normal data communication cannot perform data communication because it is not connected to the first group or the bus network. Unmonitored stations are classified into the second group. In one polling sequence, the monitoring station first sequentially makes a data request to all the monitored stations belonging to the first group, collects the data, and then
Then, a data request is made to one monitored station of the first rank among the monitored stations belonging to the second group. If the data can be normally received from the one monitored station, the monitored station is moved to the first group to collect the data from now on. 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 of the first group, and then the data request is made to one monitored station of the next order in the second group. . That is,
For the monitored station of the second group that cannot communicate, data is requested only for one monitored station per polling sequence to determine whether data communication can be normally performed, and the monitored station that requests the data Stations are moved sequentially for each polling sequence. On the other hand, when a data request is made to a monitored station of the first group but data cannot be normally received from a monitored station among them, the monitored station is moved to the second group and then , Request data to the next monitored station in the first group.

Therefore, the time required for one polling sequence is the time required to request data from all monitored stations in the first group that can communicate and the time required to collect the data, to the second group that cannot communicate. The time required to add the data request time to one monitored station in the above is eliminated, and the waste of requesting data to other monitored stations in the second group that cannot communicate is eliminated. You can Further, the monitored stations of the second group request data only for one monitored station per polling sequence, but since the monitored stations requesting the data are sequentially transferred, the second group If the monitored station can also normally perform data communication, it is possible to collect future data when the turn of polling for the monitored station comes.

[0015]

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 the bus-shaped network 1, and these monitoring stations 2 and N monitored stations are connected. Individual addresses (identifiers) are assigned to the monitoring stations 3.

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

The first storage table 4 is for storing the identifier of the monitored station 3 capable of data communication as the first group A, and the second storage table 5 is the monitored station incapable 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 order determination means 7 determines the data request order for all the monitored stations 3 of the first group A based on the identifiers stored in the first storage table 4, and also the second storage. Based on the identifiers stored in the table 5, one by one is sequentially selected from the monitored stations 3 of the second group B to determine the data request order for requesting data. In this case, the data request for one selected monitored station 3 in the second group is determined to be after the final ranked monitored station in the first group. The data requesting means 8 sends data requests to the monitored station 3 in the order according to the data requesting order determined by the data requesting order determining means 7.

The reception judging means 9 judges whether or not the data from the monitored station 3 which sent the data request could be normally received by the monitoring station 2. The rewriting means 6 is based on the judgment result of the reception judging means 9 and the first and second storage tables 4.5.
Rewrite the identifier in.

Next, the data collection operation performed by the monitoring station 2 will be described with reference to FIGS. 6 and 7. Figure 6
In the first step, the monitoring station 2 sets the first node in the second group B as the processing node b by the data request rank determining means 7 (step S1), and then sets all monitored stations in the first group A to the monitored stations. A data request is made to the data and data from the data is collected (step S2).

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

On the other hand, when the reception is not normally performed and the time-out occurs in step 13 of FIG. 7, the process proceeds to step S14, and the processing node a is deleted from the first group A and added to the second group B. . That is, the rewriting means 6 rewrites the identifier between the first storage table 4 and the second storage table 5. FIGS. 4 and 5 are schematic diagrams of the rewriting operation. When the identifier of the node a being processed is n, for example, FIG. 4 shows that this identifier n is deleted and the corresponding portion of its storage becomes empty. FIG. 5 shows that the identifier n is stored in the storage corresponding portion which has become empty.

When the data collection from the last monitored station 3 of the first group A is completed, the monitored station 3 of the group B is processed next. That is, step S in FIG.
The process moves from step 2 to step S3, and the data requesting means 8 requests the data b being processed. Then, the reception judging means 9 judges whether or not the data can be normally received from the node b being processed (step S13), and if the data cannot be normally received and a time-out occurs, a step S6 is performed.
Then, the data request rank determining means 7 determines whether the node under processing b is the last node in the second group B. If it is not the last node, next step S7
Then, the node of the second rank of the second group B is set as the data b under processing by the data request rank determination means 7, and then the process returns to step S2 to perform the processing shown in FIG. 7 again.

On the other hand, when the data is normally received in step 4 of FIG. 6, the process proceeds to step S5, and the rewriting means 6 rewrites the identifier between the second storage table 5 and the first storage table 4. Then, the node under processing 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. 6 and 7. In this case, one monitoring station 2 monitors six monitored stations 3 and
1 as an identifier (address) for one node (monitored station)
8 will be described assuming that the numerical values of 6 to 6 are respectively assigned.

First, the first group A has nodes 1 and 2
2 belong to the second group B, and nodes 3, 4, 5, ...
In the first polling sequence Sp1, the data request to the node 1 of the first group A and the data collection from it, and the data request to the node 2 and the data collection from it are sequentially performed normally. After that, when a data request is made to the first node 3 in the second group B, it indicates that the data could not be properly received from this node 3 and the time-out occurred.

In the second polling sequence Sp2, the data request to the node 1 of the first group A and the data collection from the node 1 and the data request to the node 2 and the data collection from the node 2 are normally performed, and then the second group B is collected. When a data request is made to the node 4 next to the node 4, the data can be normally collected from the node 4, so that the node 4 is moved from the second group B to the first group A.

In the third polling sequence Sp3, the data request to the node 1 of the first group A and the data collection from it, the data request to the node 2 and the data collection from it, the first group A as described above.
After the data request to the node 4 moved to the node 4 and the data collection from the node 4 are normally performed, the data is requested to the node 5 of the second group B.
Indicates that data could not be received normally from and timed out.

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. After performing normally in order, the second
When a data request is made to the last node 6 in the group B, it indicates that the data cannot be normally received from this node 6 and the time-out 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. After performing normally in order, the second
When requesting data again to the first node 3 in group B, it indicates that data could not be normally received from this node 3 and time out occurred.

In the sixth polling sequence Sp6, the data request to the node 1 of the first group A and the data collection from it could be normally performed, but the data could not be normally received from the node 2 and the timeout occurred. , This node 2 from the first group A to the second group B
After that, when the data request to the node 4 and the data collection from the node 4 are normally performed, and then the data request is made to the node 5 of the second group B, the data can be normally received from the node 5. Indicates that there was no timeout.

In the seventh polling sequence Sp7, the data request to the node 1 of the first group A and the data collection from the node 1 and the data request to the node 4 and the data collection from the node 4 are sequentially performed normally, and then the second group B is collected. When a data request is made to the last node 6, the data cannot be normally received from this node 6 and the time-out is indicated.

[0034]

As is apparent from the above description, the present invention has the following effects. Among the plurality of monitored stations, the communicable monitored station that can normally perform data communication is the first group, and the incommunicated monitored station that cannot communicate because of not being connected to the bus network is the second group. Data is collected by sequentially requesting data to all monitored stations belonging to the first group for each polling sequence, and then collecting data from the monitored stations belonging to the second group. Of 1
Since the data request is made to one monitored station and the monitored stations in the second group that request data are sequentially shifted for each polling sequence, the time required for data collection can be shortened. The monitored stations of the second group request data only for one monitored station per polling sequence. However, since the monitored stations requesting the data are sequentially moved, the monitored stations of the second group are requested. If the monitoring station can also perform normal data communication, it is possible to collect future data when the turn of polling for the monitored station comes. The processing is simple as a whole, and the data of a plurality of monitored stations can be efficiently collected in the monitoring station.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a monitoring station in a polling type data collection system 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 showing a storage mode of identifiers in the storage table in FIG.

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 data collection operation by the monitoring station.

FIG. 7 is a flowchart specifically illustrating a subroutine of the first group data collection process shown in FIG.

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

[Explanation of symbols]

 1 Bus-shaped Network 2 Monitoring Station 3 Monitored Station 4 First Storage Table 5 Second Storage Table 6 Rewriting Means 7 Data Request Order Determining Means 8 Data Requesting Means 9 Reception Determining Means

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04Q 9/00 311 J 7170-5K B 7170-5K

Claims (2)

[Claims] 1. A polling for connecting a monitoring station and a plurality of monitored stations via a bus network, polling from the monitoring station to the monitored station, and collecting data from the monitored station at the monitoring station via the bus network. In the automatic data collection method, the monitoring station stores a rewritable first storage table for storing the identifiers of monitored stations capable of data communication as a first group, and the identifiers of monitored stations not capable of data communication as a first group. A rewritable second storage table for storing as two groups, and all monitored stations belonging to the first group with reference to the identifiers stored in the first and second storage tables, Data requesting means for sending a data request to one monitored station sequentially selected from the monitored stations of the second group, and the monitored station sending the data request Polling, which comprises: reception judgment means for judging whether or not the data has been normally received, and rewriting means for rewriting the identifiers in the first and second storage tables based on the judgment result. Formula data collection method. 2. The monitoring station determines the order of the plurality of monitored stations to which the data request is to be sent by the data requesting means, based on the identifiers stored in the first and second storage tables. The polling-type data collection method according to claim 1, further comprising: a data request rank determining means for performing the above.