JPH0795218A - Data transmitting device and method - Google Patents

Abstract

PURPOSE:To exactly acknowledge the change of the state of a slave station by storing the state of the slave station at the time of failing in polling, and communicating the stored state of the slave station at the time of failing in polling and the present state of the slave station to a master station at the time of the next polling from the master station. CONSTITUTION:When normal polling response data are returned from a slave station 11 as the result of polling, a master station 1 transmits a communication success acknowledgement signal(ACK) to the slave station 11. On the other hand, when the polling response data are not returned or the abnormal response data are returned from the slave station 11, the master station transmits a communication failure acknowledgement signal(NACK) to the slave station 11. At the time of receiving the NACK, the slave station 11 stores the ON/OFF state of a contact 4 at the time of polling in a storage part 12, and transmits it with the stored previous state to the master station 1 at the time of the next polling. Therefore, even at the time of failing in polling, the state of the slave station can be exactly acknowledged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used, for example, when a power company tabulates the power meters installed in each power consumer, and the current status of a slave station in response to polling from the master station. The present invention relates to a data transmission device and method for transmitting a response data as response data to a master station. Particularly, even when response data from the slave station is not obtained in response to polling from the master station, the state change of the slave station is surely recognized. The present invention relates to a data transmission device and method capable of performing the same.

[0002]

2. Description of the Related Art Generally, as a method for an electric power company (parent station) to total the power meters (slave stations) installed in each factory or home, for example, as shown in FIG. The first communication device 1 is a plurality of second communication devices 2 as slave stations.
2, ... Are sequentially dialed via the communication line 3 to perform polling (calling), and the second communication device 2 responds to the current state, in this case, for example, the count value of the integrator or a power failure. ON / OFF status of contact 4 (S
As a V input state), a data transmission device that sequentially transmits to the first communication device 1 via the communication line 3 is used.

However, the conventional data transmission device having the above-described operation has the following drawbacks. Here, regarding the drawback of the conventional data transmission device, referring to FIG. 4, the contact ON / OFF state (SV
An example will be described in which the input state) is monitored by polling. That is, as shown in FIG.
When the N / OFF state (SV input state) is examined and monitored (in FIG. 4, only a specific slave station 2 is displayed), first, from the master station 1 to the specific slave station 2 The first polling 5 is performed with respect to. On the other hand, the SV input state at that time, that is, the OFF state is transmitted from the specific slave station 2 to the master station 1 as polling response data 6. When the polling response data 6 is notified to the master station 1, the master station 1 recognizes that the SV input state of the slave station 2 is OFF based on the polling response data 6, and polls other slave stations 2 ( (Not shown). Then, when the polling of the other slave station 2 is completed and the second polling 7 is performed from the master station 1 to the specific slave station 2, in response thereto, the SV from the specific slave station 2 at that time is sent.
The ON state which is the input state is transmitted to the master station 1 as polling response data 8. However, here, for example, noise or the like is mixed on the communication line 3 so that the polling response data 8 does not arrive at the master station 1 or the polling response data 8 arrives at the master station 1 in an unreadable state. In this case, the master station 1 determines that the polling has failed, and in this case, the ON state, which is the SV input state of the slave station 2, is not transmitted to the master station, and the previous polling data remains stored. Therefore, it is mistakenly recognized as OFF. Then, the process proceeds to polling (not shown) for the other slave station 2,
After that, the third polling 9 is performed to the specific slave station 2, the polling is successful, and the polling response data 10 in the OFF state, which is the SV input state at that time, from the specific slave station 2. Is normally received by the master station 1, the master station 1 recognizes that the SV input state is OFF, and the SV input state is OFF in all of the above three polls.
Is falsely monitored.

As described above, when the master station 1 fails in polling due to noise entering the communication line 3 or the like,
There is a drawback that the SV input state of the slave station is erroneously recognized. Therefore, the conventional data transmission device described above cannot sufficiently monitor the state of the slave station. Such a problem is not limited to the power integrator polling described above, but is a problem that occurs in polling monitoring by the same system.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and ensures a change in the state of a slave station even when response data from the slave station cannot be obtained in response to polling from the master station. It is an object of the present invention to provide a data transmission device and method that can be recognized by a user.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a master station recognizes the status of the slave station by notifying the master station of the current status as response data in response to polling from the master station. A data transmission device that has a storage means for storing the status of the slave station when there is no response from the slave station to the polling from the master station and the status of the slave station is stored at the next polling from the master station. It is characterized in that the master station is notified of the status of the slave station at the time of the polling failure and the current status of the slave station. Further, another feature of the present invention is a data transmission method in which the master station recognizes the status of the slave station by the slave station notifying the master station of the current status as response data in response to polling from the master station. When there is no response from the slave station to the polling from the master station, the status of the slave station is stored at the time of a polling failure, and at the next polling from the master station, the status of the slave station at the time of the polling failure and the current slave This is to notify the master station of the status of the station.

[0007]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is a configuration diagram showing an embodiment of a data transmission device according to the present invention, and FIG. 2 is a polling response explanatory diagram for explaining an embodiment of a data transmission method according to the present invention. In FIG. 1, in this data transmission device, a plurality of second communication devices 11, 11, ... As slave stations are connected to a first communication device 1 which is a master station via a communication line 3. The master station 1 transmits a notification success recognition signal ACK to the slave station 11 when normal polling response data is returned from the slave station 11 as a result of polling, and the slave station 1
When the polling response data is not returned from 1 or abnormal response data is returned, the notification failure recognition signal NACK is configured to be transmitted to the slave station 11, and at the same time, the slave station 11 Notification failure recognition signal N from master station 1
When an ACK is received, the SV input state at the time of polling is stored in the storage unit 12, and at the time of the next polling, the stored previous SV input state and this time SV input state are transmitted to the master station 1. Is configured.

Next, the operation of the data transmission device will be described with reference to FIG. In FIG. 2, when the master station 1 monitors the contact ON / OFF state (SV input state) of the slave station 11, the master station 1 polls the specific slave station 11 for the first time, and Then, the OFF state, which is the SV input state at that time, is transmitted from the specific slave station 11 to the master station 1 as polling response data 14. Then, when the polling response data 14 is normally notified to the master station 1, the master station 1 judges that the polling response data 14 is normal, and based on the response data 14, the SV input of the slave station 11 is performed. State is OF
A notification success acknowledge signal (ACK) 15 at the same time as recognizing F
Is transmitted to the specific slave station 11. Then, when the specific slave station 11 receives the notification success recognition signal 15 from the master station 1, it does not perform any operation.

Next, the master station 1 shifts to another slave station 11 for polling (not shown), and when that is completed, the second polling 16 is performed for the specific slave station 11. Then, in response to the second polling 16, the ON state, which is the SV input state at that time, is transmitted from the specific slave station 11 to the master station 1 as polling response data 17. Here, the communication line When, for example, noise or the like is mixed in 3 and the polling response data 17 does not arrive at the master station 1, or when the polling response data 17 arrives at the master station 1 in an unreadable state, the master station 1 When it is determined that the polling has failed, the notification failure recognition signal (NACK) 18 is transmitted to the specific slave station 11, and the recognition of the SV input state at this time is suspended. Then, when the specific slave station 11 receives the notification failure recognition signal 18, it stores the ON state, which is the SV input state at this time, in the storage unit 12.

Next, when the third polling 19 is performed on the specific slave station 11, the specific slave station 11 is executed.
Judges that the SV input state (ON state) at the time of the previous polling is stored in the storage unit 12, and therefore the master station 1 is not notified of the SV input state (ON state) at the time of the previous polling. The state change from the SV input state (ON state) at the time of the previous polling to the OFF state which is the SV input state at this time is transmitted to the master station 1 as polling response data 20. Then, when the polling response data 20 is normally notified to the master station 1, the master station 1 determines the SV of the specific slave station 11 based on the polling response data 20.
Recognize the change of the input state from ON to OFF. At the same time, the master station 1 sends the notification success recognition signal (ACK) 21.
To the specific slave station 11, and in this case, the slave station 1
1 does nothing. In the above embodiment, the next polling that failed in polling succeeds and the SV input state change of the slave station is notified at that time.
Needless to say, even if the polling fails continuously, the SV input state change may be sequentially stored in the storage unit 12 and read out when the polling is successful.

[0011]

As described above, the present invention stores the status change of the slave station when the polling from the master station fails, and notifies the master station of the stored status change when the next polling succeeds. Therefore, even if the polling fails, the change in the state of the slave station can be surely recognized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a data transmission device according to the present invention.

FIG. 2 is an explanatory diagram of a polling response for explaining an embodiment of a data transmission method according to the present invention.

FIG. 3 is a configuration diagram of a conventional data transmission device.

FIG. 4 is an explanatory diagram of a polling response for explaining a conventional data transmission method.

[Explanation of symbols]

1 ... First communication device (master station), 2, 11 ... Second communication device (slave station), 3 ... Communication line, 4
... Contacts, 5, 7, 9, 13, 16, 19 ... Polling,
6, 8, 10, 14, 17, 20 ... Polling response data, 15, 21 ... Notification success recognition signal (ACK), 18 ...
Notification failure recognition signal (NACK),

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Kuragawa, 3-9, Meidori, Izumi-ku, Sendai-shi, Miyagi Tsuken Electric Industrial Co., Ltd. No. 1 to 1 within Toyo Communication Equipment Co., Ltd.

Claims (3)

[Claims] 1. A data transmission device for recognizing the status of a slave station by the master station by notifying the master station of the current status as response data in response to polling from the master station. There is no response from the slave station to the polling of, and the storage means has a storage means for storing the status of the slave station at the time of a polling failure. A data transmission device characterized by notifying a master station of the current status of a slave station. 2. The master station transmits a notification failure recognition signal to the slave station at the time of polling failure in which there is no response from the slave station,
When the slave station receives the notification failure recognition signal, the slave station stores the state of the slave station at the time of the polling failure in the storage unit, and the content stored in the storage unit at the time of the next polling from the master station. 2. The data transmission device according to claim 1, wherein the data transmission device is configured to be added to the current slave station status for notification. 3. A data transmission method in which a master station recognizes the status of the slave station by notifying the master station of the current status as response data in response to polling from the master station. When there is no response from the slave station to the polling of or the status of the slave station is stored when the transmission failure recognition signal is sent from the master station, the status of the slave station stored at the time of the next polling from the master station is stored. A data transmission method characterized by notifying a master station of the status of the slave station and the current status of the slave station.