JPH10233792A - Polling system/method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently execute a retransmission processing when errors occur in responses from monitor controllers by permitting the plural monitor controllers to time-divisionally transmit the responses to an equipment management device through a line in accordance with a polling signal. SOLUTION: The equipment management device 11 transmits the polling signal at prescribed timing for collecting state data from the monitor controllers 21-2n. The equipment management device 11 stores the monitor controllers 21-2n from which the responses cannot be obtained for the polling signal (state data cannot be returned). When the responses cannot be received from the monitor controllers 21-2n in a block designated by the polling signal, a retransmission request is given in a block unit or an individual unit in accordance with the number of the monitor controllers 21-2n which cannot receive the response. Namely, the efficient retransmission processing is executed when the communication error occurs between the equipment management device 11 and the plural monitor controllers 21-2n.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polling method and method, and more particularly, to a polling method and method for a master station to collect and monitor the status of a slave station.

[0002]

2. Description of the Related Art In a system in which a master station collects and monitors the status of a slave station, conventionally, the master station transmits a polling signal to one slave station, and the slave station receiving the polling signal reports the status to the master. Was transmitting to the station. That is, the operation of sending a transmission request from the master station to the slave station and returning a response from the slave station to the master station has been repeated.

However, in this method, it takes time (transmission request time + response time) .times. (Number of slave stations) until the master station collects the status of all slave stations. There was such a problem.

A polling method which solves this problem and shortens the time for collecting the status of the slave station is disclosed in
274433. In this polling method, a transmission request is issued from a master station to all slave stations, and the slave stations respond at different timings. As a result, the time required for a transmission request is saved, and the time taken as a whole is reduced.

However, this polling method has the following problems. First, in this polling method, if a retransmission request is made when an error occurs in the response from the child station, the child station in which no error has occurred must also retransmit the response. For this reason, it takes the same time as in the normal case to collect responses to the retransmission request.

In this polling method, for example,
When the supervisory control device, which is a slave station, and the operation terminal that controls the supervisory control device are connected to the same line and are managed by the same master station, all the supervisory control devices become the master station. The monitoring control device cannot operate in response to an instruction from the operation terminal until a response is returned. That is,
This polling method has a problem that the response of the monitoring control device to an instruction from the operation terminal is delayed.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and a first object of the present invention is to provide a retransmission process when an error occurs in a response from a slave station. Is to provide a polling method and method for efficiently performing the polling.

A second object of the present invention is to provide a response to a command from another slave station when another slave station for operating the slave station is connected to the same line as the master station. It is an object of the present invention to provide a polling method and a polling method which can speed up the response and do not take much time to collect responses from all slave stations.

[0009]

In order to achieve the first object, a polling method according to a first aspect of the present invention comprises a master station connected to the same line and a plurality of slave stations. A polling method in a system comprising: a polling signal transmitting unit that transmits a first polling signal that specifies the plurality of slave stations in block units to the plurality of slave stations via the line. And storage means for storing information on the slave station that has not received a response to the first polling signal; counting means for counting the number of slave stations whose information is stored in the storage means; When the value counted by the counting means is equal to or more than a predetermined value, the first retransmission request means for transmitting the first polling signal again to the plurality of slave stations via the line, and the counting means A second retransmission request unit that transmits a second polling signal designating the slave station stored in the storage unit to the plurality of slave stations via the line when the value is less than a predetermined value. Wherein each of the plurality of slave stations transmits, in response to the first polling signal, the response to the master station via the line in a time-division manner within the block. And second response means for transmitting a response to the master station via the line in response to the second polling signal designating the slave station.

In the above polling method, the first
If the response cannot be received from the slave station in the block designated by the polling signal of the above, a retransmission request is made in block units or individual units according to the number of slave stations that cannot receive the response. That is, when a communication error occurs between the master station and the plurality of slave stations, retransmission processing can be performed by the most efficient method.

In order to achieve the second object, a polling method according to a second aspect of the present invention comprises a master station connected to the same line, a plurality of first slave stations, and the line. And a second slave station for giving an instruction to the plurality of first slave stations via the second slave station, wherein the master station specifies the plurality of first slave stations in block units. Polling signal transmitting means for transmitting a first polling signal to the plurality of first slave stations via the line, and the command according to a response from the first slave station to the first polling signal. Permission signal transmitting means for transmitting a permission signal for permitting transmission to the second slave station via the line,
The plurality of first slave stations respond to the first polling signal with the response to the master station via the line,
A response unit for transmitting the command in a time-division manner within the block, wherein the second slave station has a command input unit for inputting the command from outside, and a command holding unit for holding the command input from the command input unit And command transmission means for transmitting the command to the first slave station via the line in response to the permission signal transmitted from the permission signal transmission means, I do.

In the above polling method, the second
Transmitting the command from the plurality of first slave stations in the block designated by the polling signal to the first slave station after the transmission of the response to the master station is completed. Can be. Therefore, the waiting time from when the command is input from the command input means to when the command is transmitted to the first slave station can be reduced. In addition, since the response from the slave station to the master station is performed in units of blocks, the response is much faster than in the case where the response is performed in units of individual units.

[0013] To achieve the first object, a polling method according to a third aspect of the present invention is a polling method in a system including a master station connected to the same line and a plurality of slave stations. A polling signal transmitting step of transmitting a first polling signal designating the plurality of slave stations in block units from the master station to the plurality of slave stations; and the polling signal transmitted in the polling signal transmitting step. A response step of transmitting a response from the slave station to the master station in a time-division manner in response to a first polling signal; and the slave station not receiving the response transmitted in the response step. Counting step, a determining step of determining whether or not the value counted in the counting step is equal to or greater than a predetermined value, and the determining step includes: A first retransmission requesting step of retransmitting the first polling signal from the master station to the plurality of slave stations when it is determined that the value counted in step 1 is equal to or greater than a predetermined value; In response to the first polling signal transmitted in the retransmission requesting step, the slave station transmits a time-division response to the master station from the slave station; When it is determined that the value counted in the step is less than the predetermined value,
A second retransmission requesting step of transmitting a second polling signal designating the slave station in which the master station has not received the response transmitted in the response step, and a second polling signal transmitted in the second retransmission requesting step. And transmitting a response from the slave station to the master station in response to the second polling signal.

In order to achieve the second object, a polling method according to a fourth aspect of the present invention comprises a master station connected to the same line, a plurality of first slave stations, and the line. And a second slave station for giving an instruction to the plurality of first slave stations via the second slave station, wherein providing the instruction to the first slave station from the outside is performed by the second slave station. A command instructing step of instructing a slave station, a polling signal transmitting step of transmitting a polling signal designating the plurality of first slave stations in units of blocks from the master station to the plurality of slave stations, A response step of transmitting a response from the slave station to the master station in a time-division manner in response to the polling signal transmitted in the transmission step; A transmission permission step of transmitting a permission signal for permitting the command to the second slave station from the master station to the second slave station, and in response to the permission signal transmitted in the transmission permission step, A command transmission step of transmitting the command instructed in the command instructing step from the second slave station to the first slave station.

[0015]

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

FIG. 1 is a block diagram showing a configuration of a facility management system to which a polling method according to an embodiment of the present invention is applied. As shown in the figure, the facility management system includes a facility management device 1 connected to a communication line 41.
1, a plurality of monitoring control devices 21 to 2n, and an operation terminal 31
It is composed of

The equipment management device 11 is composed of a processor, a memory and the like. The facility management device 11 periodically collects status data, which will be described later, from the monitoring control devices 21 to 2n. The collected state data is temporarily stored in a memory. The memory stores information on the monitoring control devices 21 to 2n that have not received state data described below. The processor performs a predetermined process on the status data stored in the memory, and transmits a result of the process to the operation terminal 31. The processor also determines, according to the number of supervisory controllers 21 to 2n that have failed to receive the state data stored in the memory,
It is determined whether the state is a block state or an individual state request, which will be described later.

The equipment management device 11 transmits a polling signal at a predetermined timing to collect status data from the monitoring control device. The equipment management device 11 stores the monitoring control devices 21 to 2n in which no response to the polling signal is obtained (status data is not returned).
Further, when receiving the status data from all the monitoring control devices 21 to 2n in the block described later, the facility management device 11 transmits a transmission permission signal of a control message described later to the operation terminal 31. The equipment management device 11 is a master station in the equipment management system.

Devices to be monitored (hereinafter referred to as monitored devices) are connected to the monitoring control devices 21 to 2n. The monitoring control devices 21 to 2n monitor the status of the monitoring target and collect data on the status (hereinafter, referred to as status data). In addition, it controls the operation of the monitoring target device according to a control message from the operation terminal 31 described later.

Each of the monitoring control devices 21 to 2n has a unique address (1 to n). Monitoring and control device 21
To 2n are divided into blocks of a predetermined number each in the order of addresses. Each block is assigned a unique block number. Monitoring and control device 21 in one block
When receiving a polling signal designating the block from the facility management apparatus 11, each of the .about.2n transmits the status data in a time-division manner via the communication line 41 to the facility management apparatus 1.
Send to 1.

When the monitoring control devices 21 to 2n receive the polling signal from the equipment management device 11 for individually designating the devices, they individually transmit the status data to the equipment management device 11 via the communication line 41. Note that the monitoring control device 2
1 to 2n are slave stations in this facility management system.

The operation terminal 31 is installed at a remote place from the equipment management device 11 and the monitoring and control devices 21 to 2n. The operation terminal 31 includes an input device including a keyboard and the like, and an output device including a CRT and the like. The processing result of the processor of the equipment management device 11 is as follows:
Output to the output device. The operator operates the monitoring control device 2 from the input device based on the data output to the output device.
Commands for 1 to 2n are given. The operation terminal 31 generates a control message according to the command. When receiving the transmission permission from the facility management device 11, the operation terminal 31 transmits the control message to the monitoring control devices 21 to 2n. That is, the operation terminal 31 has a memory that holds the control message until receiving the transmission permission from the facility management apparatus 11.
The operation terminal 31 is another slave station in this facility management system.

The operation of the facility management system will be described below. FIG. 2 is a diagram showing a communication procedure in the polling method according to this embodiment. In this figure, the monitoring control devices 21 to 2n are divided into blocks every m units, and each block is assigned a continuous number from 1.

First, the facility management device 11 sends a polling signal (block No. 1 status request) designating the block number 1 to the monitoring control devices 21 to 2m of the block number 1 to request transmission of status data. Send via 41. Address number 1 that received this polling signal
To m transmit state data to the facility management apparatus 11 via the line 41 with a delay of the delay time Dk according to the respective addresses so that signals do not collide on the communication line 41.

As shown in FIG. 3, in the supervisory control devices 21 to 2m of the block number 1, assuming that the delay time D1 for transmitting the state data by the supervisory control device 21 of the address number 1 is 0, the address number k The delay time of

Dk = (t1 + t2) × (k−1) Here, t1 is a time required for transmitting the state data, and t2 is a margin time required to avoid collision of signals on the communication line 41.

When the monitoring control devices 21 to 2m are transmitting the status data in a time-sharing manner in response to the polling signal from the equipment management device 11, the operator operates the input device of the operation terminal 31 to transmit the status data. It is assumed that a command has been given to the monitoring control devices 21 to 2n. The control message corresponding to this command is stored in the memory of the operation terminal 31 until the operation terminal 31 receives the transmission permission signal from the facility management device 11.

Next, when all of the monitoring control devices 21 to 2m have finished transmitting the status data to the equipment management device 11, the transmission permission signal is transmitted from the equipment management device 11 to the operation terminal 31. As a result, the control message held in the memory in the operation terminal 31 is transmitted to the monitoring control devices 21 to 21 via the communication line 41.
2n. In other words, the transmission of the control message from the operation terminal 31 is performed by the monitor control
By waiting until the transmission of the status data is completed, the collision of signals on the communication line 41 is prevented.

Next, from the operation terminal 31 to the monitoring control device 21
When the transmission of the control message to .about.2n is completed, the equipment management apparatus 11 transmits a polling signal designating the monitoring control apparatus 2m + 1 to 2m + m of the next block number 2 via the communication line 41. Hereinafter, the same operation is repeated, and after the operation for the last block is completed, the operation returns to the block number 1 again and the same operation is continued.

The monitoring control device 2 of the block number b
In ((b−1) × m) +1 to 2 ((b−1) × m) + m, the monitoring control device 2 ((b−1) × m) of the address number ((b−1) × m) +1 Assuming that the delay time D (b + 1) of the time when +1 transmits the state data is 0, the delay time of the address number k is:

Dk = (t1 + t2) × ((k − ((b−1))
× m) -1).

Next, in this equipment management system, there is a communication error and the equipment management device 11
Retransmission processing when status data cannot be received from 2n will be described.

In this equipment management system, a retransmission request (block status request) of the status data is made by a polling signal designating the block in accordance with the number of the monitoring control devices 21 to 2n which could not receive the status data in one block. Or a retransmission request (individual state request) is determined by a polling signal that individually specifies the monitoring control devices 21 to 2n.

Whether the request for retransmission of state data is a block state request or an individual state request is determined depending on which method can obtain all state data faster.

In the case of a block status request, regardless of the number of monitoring control devices 21 to 2n for which status data was not obtained, all monitoring control devices 21 to 2 in the block are required.
Time is required for n to complete the transmission of state data.

The required time Tb in the case of this block state request is, as shown in FIG.

Tb = t0 + ((t1 + t2) × m) Here, t0 is a time required for transmitting the polling signal, and t2 is a margin time required to avoid collision of signals on the communication line 41.

On the other hand, the required time Ti in the case of the individual state request is, as shown in FIG.

## EQU4 ## Ti = (t0 + t2 + t1 + t2) × p Here, t1 is the time required for transmitting the status data, and p is the number of the monitoring control devices 21 to 2n for which no status data was obtained.

And

## EQU5 ## If Ti <Tb is satisfied, an individual state request is made; otherwise, a block state request is made. Here, in the case of FIG. 4, an individual state request is issued when four or less (less than five) monitoring control devices 21 to 2n for which status data cannot be obtained in one block, and a block is issued when five or more devices It becomes a status request.

Next, the retransmission processing will be described with reference to block number 1 as an example. Here, whether the retransmission processing is based on the block state request or the individual state request is based on the example in FIG. The facility management device 11 sends the monitoring control device 21
2n is stored in the internal memory. The number stored in this memory that state data has not been received is counted, and it is determined whether the request is due to a block state request or an individual state request.

As shown in FIG. 5, when no status data is obtained from one monitoring and control device 25 in response to a polling signal (request for transmission of status data for each block),
The facility management device 11 transmits a polling signal that individually specifies the monitoring control device 25. This designation is based on data on the presence or absence of a response stored in the memory in the facility management device 11. On the other hand, the monitoring control device 25 transmits the status data to the facility management device 11, and the retransmission process ends when the facility management device 11 receives the status data.

On the other hand, as shown in FIG. 6, no status data can be obtained from the five monitoring controllers 22, 23, 25, 26 and 28 in response to the polling signal (request for transmission of status data for each block). In that case, the facility management device 11
A polling signal designating block number 1 is transmitted.
Monitoring and control devices 21 to 28 that have received this polling signal
Are sequentially transmitted to the equipment management apparatus 11 with the delay time Dk in the same manner as described above.

Here, if there is any monitor / control device 21-28 that has not yet received status data due to a communication error, further retransmission processing is performed according to the number of monitor / control devices 21-28 that have not received that status data. I do.

As described above, in the equipment monitoring system of this embodiment, the monitoring control devices 21 to 2n are divided into blocks, and the equipment management device 11 sends the monitoring control devices 21 to 2n from the monitoring control devices 21 to 2n in response to the polling signal specifying the blocks. Collecting state data.

For this reason, the control terminal 31 can send a control message to the equipment management apparatus 11 when the collection of one block of state data is completed.
, The response of the monitoring control devices 21 to 2n to the command input to the monitor can be accelerated. In addition, unlike the case where the facility management apparatus 11 performs polling by individually designating the monitoring control apparatuses 21 to 2n, it does not require a long time to collect state data.

Further, the retransmission processing when a communication error occurs is performed by the monitoring control devices 21 to 2 for which the status data could not be obtained.
Depending on the number n, it depends on the faster of the block status request and the individual status request. Therefore, retransmission processing when a communication error occurs can be efficiently performed.

In the above embodiment, the equipment management device 11
In the retransmission process, whether a retransmission request is made in units of blocks or individual units is determined by comparing the times on the assumption that there is no communication error from the monitoring control devices 21 to 2n. However, communication errors can occur in the retransmission process. Therefore, if a communication error occurs in the retransmission processing in block units, it may take longer than when a retransmission request is made in individual units. For this reason, the equipment monitoring apparatus 11 may determine whether to perform the retransmission processing in block units or individual units in consideration of the probability of such a communication error.

In the above embodiment, when a communication error occurs, retransmission processing is performed by selecting either the block unit or the individual unit, whichever is shorter in processing time. However, it is also possible to perform all retransmission processing in block units or individual units. In this case, it is easy to control the resending process in the facility management apparatus 11 while securing the response speed to the instruction from the operation terminal 31.

In the above embodiment, when there is a communication error, the facility management apparatus 11 issues a transmission permission to the operation terminal 31 after the retransmission processing is completed. However, the retransmission process may be performed after the transmission permission for the operation terminal 31 is issued. Thereby, the operation terminal 3
1 to the response to the instruction given to the monitoring control devices 21 to 2n can be made faster.

In the above embodiment, the equipment management device 11
The operator operates the operation terminal 31 to send a control message to the monitoring control devices 21 to 2n based on the information indicating the state of the monitoring control devices 21 to 2n collected by the user, thereby controlling the operation of the monitoring control devices 21 to 2n. Was. However, the present invention is not limited to this. For example, the equipment management apparatus 11 and the operation terminal 31 may be connected by another dedicated line, and the operation terminal 31 may generate a control message by performing a predetermined operation on data obtained from the equipment management apparatus 11.

In the above embodiment, only one operation terminal 31 is connected to the communication line 41. However, the present invention can also be applied to a facility management system in which a plurality of operation terminals are connected to the communication line 41. In this case, the facility management apparatus 11 may issue a transmission request to a plurality of operation terminals in order.

In the above embodiment, the operation terminal 31 which is also a slave station is connected to the communication line 41 which connects the facility management apparatus 11 which is the master station and the monitoring control devices 21 to 2n which are slave stations. . However, such an operation terminal 31
The polling method of the present invention can also be applied to a facility management system that is not connected to the same communication line 41.

In the above embodiment, a case has been described in which the present invention is applied to an equipment management system in which the master station is the equipment management apparatus 11 and the slave stations are the monitoring control apparatuses 21 to 2n.
However, the present invention is not limited to this. The present invention
The present invention can be applied to any system in which a transmission request is sent from a master station to a slave station by polling, and the slave station receiving the transmission request sends a response to the master station.

[0051]

As described above, according to the present invention,
It is possible to efficiently perform retransmission processing when an error occurs in a response from a slave station.

When another slave station for operating the slave station is connected to the master station on the same line, the response to the command from the other slave station can be made faster.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a facility management system to which a polling method according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a communication procedure in the polling method according to the embodiment of the present invention.

FIG. 3 is a timing chart of communication in the polling method according to the embodiment of the present invention.

FIG. 4 is a timing chart for comparing required times when a transmission request is made in block units and when a transmission request is made in individual units.

FIG. 5 is a diagram illustrating a communication procedure (individual units) of retransmission processing when a communication error occurs in the polling method according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a communication procedure (in blocks) of a retransmission process when a communication error occurs in the polling method according to the embodiment of the present invention.

[Explanation of symbols]

 11 Equipment management device 21-2n Monitoring and control device 31 Operation terminal 41 Communication line

Claims (4)

[Claims] 1. A polling system in a system including a master station connected to the same line and a plurality of slave stations, wherein the master station specifies a plurality of slave stations in block units. Polling signal transmitting means for transmitting the polling signal to the plurality of slave stations via the line, and storage means for storing information on the slave stations that did not receive a response to the first polling signal, Counting means for counting the number of the slave stations in which the information is stored in the storage means; and when the value counted by the counting means is equal to or greater than a predetermined value, the first polling signal is transmitted to the plurality of stations via the line. First retransmission requesting means for retransmitting to the slave station, and a second polling signal designating the slave station stored in the storage means when the value counted by the counting means is less than a predetermined value. Second retransmission request means for transmitting a signal to the plurality of slave stations via the line, wherein each of the plurality of slave stations responds to the first polling signal and transmits the response to the line. A first responding means for transmitting to the master station in a time-division manner within the block, and a second polling signal designating the slave station,
Transmitting a response to the master station via the line;
And a response means. 2. A master station each connected to the same line, a plurality of first slave stations, and a second slave station for giving a command to the plurality of first slave stations via the line. A polling method in a system comprising: the master station sends a first polling signal designating the plurality of first slave stations in units of blocks to the plurality of first slave stations via the line. A polling signal transmitting means for transmitting the command to the second slave station according to a response from the first slave station to the first polling signal. And a permission signal transmitting unit that transmits the response to the master station via the line in response to the first polling signal. Time-division within The second slave station includes: a command input unit that inputs the command from outside; a command holding unit that holds the command input from the command input unit; and a transmission unit that transmits the permission signal. Command transmission means for transmitting the command to the first slave station via the line in response to the granted permission signal. 3. A polling method in a system including a master station connected to the same line and a plurality of slave stations, wherein a first polling signal designating the plurality of slave stations in a block unit is provided. A polling signal transmitting step for transmitting from the master station to the plurality of slave stations; and the first polling signal transmitted in the polling signal transmitting step.
A response step of transmitting a response from the slave station to the master station in a time-sharing manner in response to the polling signal of the slave station; and counting the slave stations in which the master station did not receive the response transmitted in the response step. A counting step for determining whether or not the value counted in the counting step is equal to or greater than a predetermined value; and in the determining step, determining that the value counted in the counting step is equal to or greater than the predetermined value. A first retransmission requesting step of retransmitting the first polling signal from the master station to the plurality of slave stations; and responding to the first polling signal transmitted in the first retransmission requesting step. A first re-response step of transmitting a response from the slave station to the master station in a time-division manner; and, in the determining step, the value counted in the counting step is less than a predetermined value. When it is determined that, first transmits the second polling signal for specifying the slave station which has not the transmitted the response at the response step received by the master station 2
And a second re-response step of transmitting a response from the slave station to the master station in response to the second polling signal transmitted in the second re-transmission request step. A polling method comprising: 4. A master station connected to the same line, a plurality of first slave stations, and a second slave station for giving a command to the plurality of first slave stations via the line. A polling method in a system comprising: a command instructing step of externally instructing the second slave station to give the command to the first slave station; and a block unit of the plurality of first slave stations. A polling signal transmitting step of transmitting a polling signal specified by the master station to the plurality of slave stations; and, in response to the polling signal transmitted in the polling signal transmitting step, the slave station sends the polling signal to the master station. A response step of transmitting a response in a time-division manner, and according to the response transmitted in the response step, a permission signal for permitting the command to the second slave station from the master station to the second slave station. And transmitting the command instructed in the command instructing step from the second slave station to the first slave station in response to the permission signal transmitted in the transmission permitting step. A polling method, comprising: transmitting a command to the apparatus.