JPH11243406A - Data communication method, communication terminal and terminal controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To send a response telegraphic message at a different timing and to avoid the collision of response telegraphic messages with each other on a communication line by detecting the receiving of a batch request telegraphic message, storing an inherent identification number in a self-station, calculating a response waiting time that is the function of the identification number and sending the response telegraphic message after the response waiting time passes, in response to the receiving of the batch request telegraphic message. SOLUTION: A response timing setting part 14 selects a waiting time setting number N and notifies it to a polling part 11 and the part 11 produces a batch request telegraphic message, that stores a selected waiting time setting number '1' in an information part and sends it onto a communication line 3. When a polling detecting part 21 detects the batch request telegraphic message, each communication terminal 2 checks an address notified flag that is set, when the registration of an address on a master station 1 is completed. The number N of the batch request telegraphic message which is included in the information part is extracted and notified to a waiting time operating part 24, and a waiting time coefficient is calculated by function calculation based on the address of a self-station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication method in which a plurality of communication terminal devices as slave stations transmit data in response to a batch polling by a terminal control device as a master station, and a communication terminal device and terminal control. More particularly, the present invention relates to a data communication method in which each communication terminal that has received a data request by collective polling transmits response data at different timings, a communication terminal device, and a terminal control device.

[0002]

2. Description of the Related Art Generally, in a 1: n multi-drop communication system in which a plurality of communication terminals (child stations) are connected to one master station by half-duplex communication, the master station sends a batch request message. When collecting data (response message) from each communication terminal by batch polling, if each communication terminal sends a response message at once in response to the batch request message, the response messages collide on the line. . A so-called "bisection method" has been proposed as a collective polling method for solving such problems and collecting response messages sent from each communication terminal in response to the collective request message without collision. I have.

In the "bisection method", first, collective polling is performed for all of a plurality of communication terminals, and when a collision occurs in a response message transmitted from each communication terminal, the plurality of communication terminals are connected to two communication terminals. Divide into two groups, and perform collective polling separately for each group. Here, if a collision occurs in the response message, each group is further divided into two, and the division is repeated until the collision does not occur.

[0004]

In the prior art described above, when the number of communication terminals is M, a maximum of log ₂ M polling is required until collision does not occur in the response message. For this reason, there has been a problem that a large amount of time is spent when the number of communication terminals increases.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a data communication method in which each communication terminal which has received a data request simultaneously by collective polling transmits response messages at different timings. And a communication terminal device and a terminal control device.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention is characterized in that the following means are taken. (1) A communication terminal device according to the present invention includes: a detecting unit that detects reception of a batch request message; a unit that stores an identification number unique to the own station; and an arithmetic unit that calculates a response waiting time that is a function of the identification number. And sending means for sending a response message after the response waiting time elapses in response to the reception of the batch request message.

According to the above configuration, when the master station sends a batch request message, a response waiting time is obtained based on the identification number, and the response message is sent after the response waiting time has elapsed. Therefore, even when a plurality of communication terminal devices simultaneously receive the batch request message, response messages are transmitted from each communication terminal device at different timings. (2) The terminal control device of the present invention includes: a polling unit that transmits a batch request message including a waiting time setting number; a collision determination unit that determines whether there is a collision between response messages; and registers a normally received response message. Means for re-transmitting a batch request message including a different waiting time setting number when a collision occurs in the response message.

According to the above configuration, when a collision occurs between response messages sent from a plurality of communication terminal devices with a batch request message including a waiting time setting number sent by itself, another waiting time different from the previous time is used. A batch request message including the setting number is sent. Therefore, if the timing at which a response message is sent from the communication terminal device is a function of the waiting time setting number,
A response message can be transmitted from each communication terminal device at a different timing. (3) In the data communication method of the present invention, the master station instructs a certain function calculation and sends a batch request message. Each communication terminal device calculates the response wait time by executing the above-described function calculation for the identification number unique to the own station, and sends a response message after the response wait time has elapsed. When detecting the collision of the response message transmitted from each communication terminal device, the master station instructs another function calculation different from the previous one and retransmits the batch request message.

According to the above-described configuration, a batch request message is transmitted from the master station, and the response waiting times obtained by the function calculation indicated here coincide with each other accidentally in a plurality of communication terminal devices. Even if the messages collide, in the next batch request message, a function calculation different from the previous one is instructed, so that each response message can be sent at a different timing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a main part of a data communication system to which the present invention is applied. More specifically, FIG. 1 is a block diagram of an automatic meter reading system to which the present invention is applied.
Are connected in a multi-drop mode, and both perform data communication by a half-duplex communication method. Each communication terminal 2 has an electronic meter 4 such as an electronic power meter or an electronic gas meter.
Are connected, and the meter readings from each electronic meter 4 are transmitted to the master station via each communication terminal 2.

In the automatic meter reading system having such a configuration,
When the electronic meter 4 is newly installed, it is necessary for the master station 1 to notify the master station 1 of information for identifying each electronic meter 4, that is, the address of each communication terminal 2 before the meter reading. . For this reason, the master station 1 collectively polls the communication terminals 2 of all the newly installed electronic meters 4 in advance and sends the addresses, collects and manages the addresses. Hereinafter, the present invention will be described by taking as an example a case where the master station 1 collects the addresses of the respective communication terminals 2 by collective polling as described above.

In the master station 1, a communication interface (I / F) 10 controls connection between the own station and the communication line 3. The polling unit 11 sends a message for collectively requesting the return of addresses (hereinafter, referred to as a batch request message).
And a message for individually requesting return of maintenance data such as a meter reading value (hereinafter, referred to as a maintenance request message) is transmitted to the communication line 3 via the communication I / F 10.

The collision judging unit 12 judges whether or not there is a collision between the response messages sent from the respective communication terminals 2 in response to the batch request message. The address registration unit 13 registers an address included in a response message received without colliding with another response message. The response timing setting unit 14 inserts a waiting time setting number N described later in detail into the batch request message.
The maintenance data collection unit 15 collects maintenance data transmitted from each electronic meter 4 in response to the maintenance request message.

On the other hand, in the communication terminal 2, the communication I / F 2
0 controls the connection between the own station and the communication line 3. The polling detection unit 21 detects a batch request message and a maintenance request message sent from the master station 1. Address storage unit 22
Stores an address which is an identification number unique to the own station. When the batch request message is detected by the polling detection unit 21, the waiting time calculation unit 24 stores the waiting time setting number N in the message and the address stored in the address storage unit 22, as described later in detail. The waiting time ΔTn is calculated based on the waiting time ΔTn.

When the batch request message is detected, the response message sending unit 23 sends a response message including the address stored in the address storage unit 22 onto the communication line 3 after the elapse of the waiting time ΔTn. The data transmission unit 25 transmits maintenance data in response to the maintenance request message. The I / F 26 controls connection between the own station and the electronic meter 4.

FIG. 2 is a diagram for explaining the operation of the waiting time calculator 24 of the communication terminal 2. In order to calculate the waiting time ΔTn based on the waiting time setting number N sent from the master station 1, the waiting time calculating unit 24 includes a plurality of waiting time setting numbers N (“1” to “1” in the present embodiment).
For each “6”), the contents of the function calculation to be executed for the address of the own station are registered.

In this embodiment, the waiting time setting number "1"
For, a function for adding the lower one digit and the lower two digits of the address is registered. Similarly, the waiting time setting number “2”
For, the function of adding the lower one digit and the lower three digits, for the waiting time setting number “3”, the function of adding the lower one digit and the lower four digits, and the waiting time setting number “4” For, the function of adding the lower two digits and the lower three digits, for the waiting time setting number “5”, the function of adding the lower two digits and the lower four digits, and for the waiting time setting number “6” For, a function for adding the last three digits and the last four digits is registered.

For example, when the address of the own station is "9082", as shown in FIG. 2, when "1" is inputted as the waiting time setting number, the lower one digit "2" and the lower two digits are inputted. “8” is added to obtain “10” as the waiting time coefficient k. Similarly, when the waiting time setting number “2” is input, the last one digit “2” and the last three digits “0” are added to obtain the waiting time coefficient “2”.

When the waiting time coefficient k is obtained in this way, the waiting time calculating unit 24 further sets the product of the waiting time coefficient k and the unit time T0 as the current waiting time ΔTn. The unit time T0 is a value obtained by adding a predetermined safety factor (margin) to the time required for sending a response message, and is set to 300 ms in the present embodiment. Therefore, as shown in FIG. 2, if the waiting time coefficient k is “10”, the waiting time ΔTn becomes 3000 ms, and if the waiting time coefficient k is “2”, the waiting time ΔTn becomes 600 ms.

FIG. 3A is a diagram showing a data format of the batch request message transmitted from the master station 1 to each communication terminal 2, and FIG. FIG. 3 is a diagram showing a format of the response message to be transmitted to No. 1;

The batch request message includes a start text (STX) having a data length of “1”, a common portion having a data length of “13”, an information portion having a data length of “1”, and an end text having a data length of “1” ( ETX) and a block check sequence (BCC) having a data length of “2”.
The format of the response message is also as shown in Fig.
The configuration is the same except that the information section for storing the waiting time setting number N is not included.

The common part includes a data length area having a data length of "3", an information type area having a data length of "1", an address area having a data length of "6", and a port No. having a data length of "1".
An area and a type code area having a data length of “2”.

Hereinafter, the operation of the present embodiment will be described with reference to flowcharts and protocol sequences. FIG. 5 is a flowchart showing the operation of the master station 1, and FIG. 6 is a diagram showing the operation of the communication terminal 2. 7 and 8
3 is a diagram showing an example of communication between a master station 1 and a communication terminal 2. FIG. In the present embodiment, a description will be given assuming that five communication terminals 2 (2a, 2b, 2c, 2d, 2e) are connected to one master station 1.

In the master station 1, at step S100, T
One timer (not shown) starts. The T1 timer is a cycle in which the master station 1 repeats sending a batch request message to each communication terminal 2, and is set to 5 minutes in this embodiment. In step S101, the response timing setting unit 14 selects the current waiting time setting number N and notifies the polling unit 11. Here, a description will be given assuming that "1" is initially selected as the waiting time setting number N. In step S102, the polling unit 11 creates a batch request message in which the selected waiting time setting number “1” is stored in the information unit, and sends the message to the communication line 3.

At this time, in each communication terminal 2, step S
When the polling detection unit 21 detects the batch request message in 200, in step S201, the address notification completion flag set when the registration of the address to the master station 1 is completed is checked. Here, since it has not been set yet, the process proceeds to step S202. In step S202, the T2 timer 27 starts.

The T2 timer 27 is a timer for measuring an elapsed time from the detection of the batch request message. In step S203, the waiting time setting number N included in the information part of the batch request message is extracted and notified to the waiting time calculation unit 24. In step S204, the waiting time setting number N
The waiting time coefficient k is calculated by the function calculation described with reference to FIG. 2 based on the address of the own station stored in the address storage unit 22.

FIG. 4 shows each communication terminal 2 in this embodiment.
FIG. 6 is a diagram showing a relationship between addresses a to 2e and a waiting time coefficient k obtained for each waiting time setting number N. In the present embodiment, as described above, initially, the waiting time setting number N
Is extracted, the address “2002” is extracted.
In the communication terminal 2a, "2" is obtained as the waiting time coefficient. Similarly, in the communication terminal 2b having the address “2322”, the waiting time coefficient “4” is obtained, and the address “363” is obtained.
In the communication terminal 2c of "1", the waiting time coefficient "4" is obtained. In the communication terminal 2d of the address "5678", the waiting time coefficient "15" is obtained. In the communication terminal 2e of the address "7830", the waiting time coefficient is obtained. The coefficient "3" is obtained.

In step S205, the product of the waiting time coefficient k and the unit time (300 ms in this embodiment) is obtained as the waiting time ΔTn. In step S206,
It is determined whether or not the waiting time ΔTn obtained for the own station matches the time counted by the T2 timer 27. When a metal line is used as a communication line, a predetermined standby time (180 ms in the present embodiment) is required from reception of a message to transmission of the message due to its characteristics. For this reason, in the present embodiment, the time counted by the T2 timer 27 is 1
The timing time obtained by subtracting 80 ms is compared with the waiting time ΔTn. In the following description, the timing time of the T2 timer 27 is a timing start timing that is 180 ms after the batch request message is detected. And

Such timing correction can be made by, for example, setting the initial value of the T2 timer 27 to -180 ms in advance, or comparing the value obtained by adding 180 ms to the waiting time ΔTn with the time measured by the T2 timer 27. Can be achieved.

In step S206, the waiting time ΔT
If it is determined that the n and the time counted by the T2 timer 27 match, the response message returning unit 23
Is sent to the communication line 3 in step S207.

That is, as shown in FIG. 7, when the T2 timer measures 600 ms from the reference timing, a response message including the address "2002" is transmitted from the communication terminal 2a, and when the T2 timer measures 900 ms, communication starts. When a response message including the address “7830” is transmitted from the terminal 2e and the T2 timer measures 1200 ms, the communication terminals 2b and 2c transmit the address “2322”,
Response messages each containing “3631” are sent out, and T2
When the timer counts 4500 ms, a response message including the address “5678” is transmitted from the communication terminal 2d.

At this time, the master station 1 first receives a response message including the address “2002” in step S103, and in step S104, the collision determination unit 12 determines whether the response message has been normally received. Is determined. In the present embodiment, as illustrated in FIG. 7, the response message including the address “2202” is normally received without colliding with another response message, and therefore, in step S105, the address “2202” is stored in the address registration unit 13. Registered in. In step S106, the T1 timer is referred to,
If the timeout has not occurred, the process returns to step S103 and waits for the next response message. In the present embodiment, as illustrated in FIG. 7, the response message including the address “7830” is normally received without colliding with another response message. Therefore, in step S105, the address “7830” is registered in the address registration. Registered in the unit 13.

Returning to step S103, as shown in FIG. 7, a response message including the address "2322" and a response message including "3431" are detected. However, since the response messages collide, the address included in each response message is not registered in the address registration unit 13, and the process returns to step S103 via step S106. In step S103, as illustrated in FIG. 7, a response message including the address “5678” is received this time, and this is also normally received without colliding with another response message. Therefore, in step S105, the address “5678” is received. Is registered in the address registration unit 13.

As described above, in this embodiment, the waiting time ΔT
Since n is an integral multiple of the unit time T0 (300 ms),
If the waiting time coefficient k is different, collision of response messages sent from each communication terminal 2 can be avoided.

Thereafter, when a timeout of the T1 timer is detected in step S106, step S107 is performed.
Then, it is determined whether or not the response message has been newly registered in the address registration unit 13. Here, since three addresses have been newly registered, the process proceeds to step S108. Step S108
In, a maintenance request message is sent to a communication terminal whose address is newly registered.

Here, three communication terminals 2a, 2d, 2
e of addresses “2202”, “7830”, “587”
8 ”is newly registered. In the first step S108, the address“ 220 ”is sent from the polling unit 11 of the master station 1.
A maintenance request message including "2" is transmitted.

At this time, when the communication terminal 2a detects a maintenance request message addressed to itself at step S210 in FIG.
The meter reading value is received via / F26, and is sent from the data sending unit 25 as maintenance data.

When receiving the maintenance data sent from the communication terminal 2a in step S109, the master station 1 stores it in the maintenance data collection unit 15. In step S110, as shown in FIG. 7, a registration confirmation end message is sent to the slave unit 2a. At this time, when the communication terminal 2a detects the registration confirmation end message addressed to its own station in step S212,
At 213, the address notification flag is set.

When the master station 1 sends a registration confirmation end message, it is determined in step S111 whether or not all maintenance requests for newly registered communication terminals have been completed. In the present embodiment, the communication terminals 2d (address “7830”) and 2e (address “587”)
Since the maintenance request regarding 8 ″) has not been completed, the processing of steps S108 to S111 is repeated, and the maintenance data of the communication terminals 2d and 2e are also stored in the maintenance data collection unit 15, as illustrated in FIGS. .

Thereafter, in the master station 1, when the T1 timer times out in step S112, the process returns to step S100, and after restarting the T1 timer, in step S101, the response timing setting unit 14
However, this time, “2” is selected as the waiting time setting number N and the polling unit 11 is notified. In step S102, the polling unit 11 creates a batch request message in which the waiting time setting number "2" is stored in the information unit and sends the message to the communication line 3 in the same manner as described above.

At this time, as shown in FIG. 4, in the communication terminal 2b of the address "2322", the waiting time coefficient "5"
Is calculated, and the communication terminal 2c at the address “3631” obtains the waiting time coefficient “7”. Therefore, FIG.
When the T2 timer 27 measures 1500 ms from the reference timing, a communication message including the address “2322” is transmitted from the communication terminal 2b, and when the T2 timer 27 measures 2100 ms, the communication terminal 2c measures the address “ 3631 "is sent out, so that each response message does not collide,
The signal is normally received by the master station 1.

Thereafter, the processing of the master station 1 is repeated at step S1.
01, the waiting time setting number N is set to "3"
Is selected, and the polling unit 11 creates a batch request message in which the waiting time setting number “3” is stored in the information unit and sends it out to the communication line 3 in step S102. However, in the present embodiment, all the communication terminal devices 2a to 2e
Has already been completed, and all the address notification flags of the communication terminals 2 have been set.
Therefore, no new address is registered even after the T1 timer times out in step S106, and the process ends after step S107.

According to the present embodiment, each communication terminal 2 that has received the batch request message transmitted from the master station 1 obtains a response waiting time ΔTn based on an address unique to its own station, and responds from a scheduled timing. Since the response message is sent after the elapse of the waiting time ΔTn, the response message is sent from each communication terminal 2 at a different timing, so that collision of each response message on the communication line 3 can be substantially avoided. become.

In the above-described embodiment, each communication terminal 2 has been described as setting the timing after the elapse of the standby time of 180 ms from the reception of the batch request message as the timing to start the measurement of the standby time ΔTn. However, if the communication line does not need to set a waiting time between receiving the batch request message and sending the response message, the reception detection timing of the batch request message should be set to the timing start timing. It is good.

[0045]

According to the present invention, the following effects are achieved. (1) According to the communication terminal device of the present invention, when a batch request message is sent from the master station, a response waiting time is obtained based on an identification number unique to the own station, and after the response waiting time elapses, A message is sent. Therefore, even when a plurality of communication terminal devices simultaneously receive the batch request message, response messages are transmitted from each communication terminal device at different timings,
Collision between response messages on the communication line can be substantially avoided. (2) According to the terminal control device of the present invention, if a collision occurs in response messages sent from a plurality of communication terminal devices for a batch request message including a waiting time setting number, a different waiting time setting from the previous time is set. A batch request message including the number is sent. Therefore, if the timing at which a response message is sent from the communication terminal is set as a function of the waiting time setting number, the response message can be sent at a different timing from each communication terminal, and collision of the response message on the communication line can be prevented. It can be substantially avoided. (3) According to the data communication method of the present invention, the master station sends a batch request message by instructing a certain function calculation, and when detecting a collision of response messages sent from each communication terminal device, A different function calculation different from the above is instructed and the batch request message is retransmitted. Therefore, even if the response waiting times obtained by the function calculation first instructed by the master station coincidentally coincide with each other in a plurality of communication terminal devices, and these response messages collide, the next batch request message will not Since a different function calculation is instructed, each response message can be transmitted at a different timing.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of a data communication system to which the present invention is applied.

FIG. 2 is a diagram for explaining an operation of a waiting time calculation unit 24 of the communication terminal 2;

FIG. 3 is a diagram showing a format of a batch request message and a response message.

FIG. 4 is a diagram showing a relationship between addresses of communication terminals 2a to 2e and a waiting time coefficient k obtained for each waiting time setting number N.

FIG. 5 is a flowchart showing an operation of the master station 1;

FIG. 6 is a diagram illustrating an operation of the communication terminal 2.

FIG. 7 is a diagram (part 1) illustrating an example of communication between a master station 1 and a communication terminal 2;

FIG. 8 is a diagram (part 2) illustrating a communication example between the master station 1 and the communication terminal 2.

[Description of Signs] 1 ... Master station, 2 ... Communication terminal, 3 ... Communication line, 4 ... Electronic meter, 10, 20 ... Communication I / F, 11 ... Polling unit, 1
2 ... collision determination unit, 14 ... response timing setting unit, 21 ...
Polling detection unit, 24 ... wait time calculation unit

Claims (12)

[Claims] 1. A communication terminal device for detecting a data request by polling and transmitting a response message, detecting means for detecting reception of a batch request message, means for storing an identification number unique to the own station, A communication terminal device, comprising: a calculating means for calculating a response waiting time as a function of a number; and a transmitting means for transmitting a response message after the response waiting time elapses in response to reception of a batch request message. 2. The communication terminal device according to claim 1, wherein the calculating means determines the contents of the function based on a waiting time setting number notified via a communication line. 3. The communication terminal device according to claim 1, wherein the transmitting unit transmits the response message after a response waiting time has elapsed from the reception detection timing of the batch request message. 4. The communication terminal device according to claim 1, wherein the transmitting unit transmits the response message after a lapse of a scheduled time and the response waiting time from the reception detection timing of the batch request message. 5. The communication terminal according to claim 1, wherein said calculating means sets a product of a multiplication coefficient corresponding to said identification number and a predetermined unit time as a response waiting time. apparatus. 6. The response waiting time according to claim 3, wherein the calculation means sets a value obtained by adding a scheduled time to a product of a multiplication coefficient corresponding to the identification number and a scheduled unit time. Communication terminal device. 7. The communication terminal device according to claim 5, wherein the unit time is longer than a time required for transmitting a response message. 8. The communication terminal device according to claim 5, wherein the multiplication coefficient is a sum of numerical values of a plurality of digits of an identification number. 9. The communication terminal device according to claim 8, wherein the combination of digits to be added is determined based on a waiting time setting number notified via a communication line. 10. A terminal control device that functions as a master station of the communication terminal device according to any one of claims 2 to 9, sends a batch request message to each communication terminal device, and collects a response message. A polling unit for sending a batch request message including a time setting number; a collision determining unit for determining whether there is a collision between response messages; and a response message registering unit for registering a normally received response message. The terminal control device retransmits a batch request message including a different waiting time setting number when a collision occurs in the response message. 11. A data communication method in which a plurality of communication terminal devices send a response message in response to a batch request message sent from a master station, wherein the master station instructs a certain function calculation to execute the batch request message. In response to the reception of the batch request message, each communication terminal device executes the instructed function calculation for the identification number unique to its own station to obtain a response waiting time, and When the response message is transmitted after the elapse of the waiting time, and the master station detects a collision of the response messages transmitted from the respective communication terminal devices, the master station instructs another function calculation different from the previous time to output the batch request message. A data communication method characterized by retransmitting. 12. The data communication method according to claim 11, wherein the instruction of another function calculation and retransmission of the batch request message are repeated until collision of response messages is not detected.