JPH08251208A - Polling system - Google Patents

Abstract

PURPOSE: To facilitate a move control of a polling station and to perform the operation proper for a communication line fault by stopping a polling operation when it is recognized that the priority of its own station is low while the its own station and the other station perform the polling operations. CONSTITUTION: A polling control part 10 is provided with a reception part 11, transmission part 12, processing part 13, setting part 14 and timer 15. The reception part 11 receives a signal sent from the transmission part 12 through a line and outputs it to the processing part 13. Then, the processing part 13 starts/stops the polling operation of its own present station, and the setting part 14 sets the priority order for applying the polling right. First of all, the signal outputted from the reception part 11 is received for fixed time while referring to the time measuring signal of the timer 15 and during this operation, the polling signal is recognized together with the peculiar number of that station. In this case, it is judged whether the other station performs polling or not and when polling is performed, it is judged while referring to its own priority order at the setting part 14 whether polling at the present station can be most preferentially performed or not. When its rank is low, the polling operation is stopped.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polling system. This polling method is applied to remote monitoring of a slave station in a wireless or wired communication system, and a polling signal is sequentially transmitted from a master station determined to perform polling control to a plurality of slave stations. It is to obtain the monitoring information of the slave station which is returned in response to the request.

[0002]

2. Description of the Related Art FIG. 9 is a communication system diagram for explaining a conventional polling method. In this figure, 1 is a master station, 2 ₁ , 2 ₂ , ... 2 _n are a plurality of slave stations. The master station 1 is defined as a polling station for performing polling control. The polling order for each of the slave stations 2 _{1 to} 2 _n is predetermined, and the master station 1 performs polling in accordance with the order.

The master station 1 transmits polling signals P1, P2, ..., Pn in the order determined by the slave stations 2 ₁ to 2 _n .
The slave stations 2 _{1 to} 2 _n respond to the polling signals P1 to Pn with response signals A1, A2, ..., An including monitoring information and the like.
Is transmitted to the master station 1.

The master station 1 receives the transmitted response signal A
The states of the slave stations 2 ₁ to 2 _n are recognized from ₁ to _An .

[0005]

By the way, in the above-mentioned conventional polling system, the number of the master stations 1 which are polling stations is limited to one.
There was a problem that polling could not be performed if some failure occurred in the.

However, even if a plurality of parent stations are installed by some means such as moving the polling station, the control procedure is complicated and the polling station cannot be easily moved.

Further, since there is only one polling station, when a failure occurs in the communication line, there is a problem that the lower stations from the failure occurrence point cannot be polled and all the lower stations cannot be monitored.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a polling method capable of performing proper polling when a communication line fails by facilitating movement control of a polling station. Has an aim.

[0009]

FIG. 1 shows the principle of the present invention. In the polling method, a master station sequentially polls a plurality of slave stations and receives a response signal to monitor and control the plurality of slave stations.

The polling system of the present invention is realized by equipping a plurality of master stations and a plurality of slave stations connected by a full-duplex line with each means shown in FIG. In the figure,
Reference numeral 21 denotes a polling control means, which performs a polling operation by transmitting a polling signal from its own station to another station. Reference numeral 22 is a receiving means, which receives a polling signal sent from another station.

Reference numeral 23 denotes another station polling recognition means, which recognizes that another station is performing a polling operation when the polling signal is received by the receiving means 22.
Reference numeral 24 is a local station polling recognition means, which recognizes that the local station is performing a polling operation when the polling control means 21 is activated.

Reference numeral 25 is a setting means for setting priority information of polling rights. Reference numeral 26 is a priority recognizing means, which recognizes from which station the polling signal received by the receiving means 22 is, and the priority information indicating the high / low priority of the recognized station and its own station. Is recognized by referring to.

Numeral 27 is a polling activation means, which polls the polling control means 21 when the other station and its own station polling recognition means 23 and 24 recognize that neither the other station nor its own station is performing the polling operation. It is the one that activates the operation.

Numeral 28 is a polling stopping means, which is recognized by the other station and its own station polling recognition means 23 and 24 that both the other station and its own station are performing the polling operation, and the priority recognition means 26 shows the own station. The polling operation of the polling control means 21 is stopped when it is recognized that the priority is low.

[0015]

According to the present invention described above, when the receiving means 22 does not receive the polling signal from the other station, the other station polling recognizing means 23 recognizes that the other station is not performing the polling operation. When the own station polling recognition means 24 recognizes that the own station is not performing the polling operation, the polling activation means 27 activates the polling operation by the polling control means 21,
As a result, the polling signal is transmitted from the own station to other stations. That is, the own station gets the polling right.

On the other hand, when the receiving means 22 receives the polling signal, the other station polling recognition means 23 recognizes that the other station is performing a polling operation, and at this time, the own station polling recognition means 24 recognizes the own station. Is recognized as performing the polling operation, and when the priority recognizing means 26 further recognizes that the polling right of the own station has a lower priority than the other station to which the reception polling signal is transmitted, the polling stopping means. 28 is polling control means 2
The polling operation by 1 is stopped. That is, the local station loses the polling right.

Therefore, the number of polling stations is not limited to one as in the conventional case, and when the polling signal cannot be transmitted to all the managed stations due to a line failure or the like, the polling right is moved to poll other stations. It becomes possible to be a station.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a configuration of a communication system for explaining a polling method according to an embodiment of the present invention.

[0019] In this figure, reference numeral 3 ₁ to 3 _m is more than one parent station, 4 ₁ to 4 _n is a plurality of slave stations, P is the polling station is connected on each duplex line. Polling station P
Is that the master station or the slave station functions as a polling station by acquiring the polling right.

The polling station denoted by P'will be described later when the polling station P cannot poll any of the master stations 3 _{1 to} 3 _m and the slave stations 4 ₁ to 4 _n due to a line failure. According to the priority described, the polling right is given to the other master station or the slave station, whereby the polling station functions.

Although the polling station P'is shown above,
The other master stations 3 _{1 to} 3 _m and the slave stations 4 ₁ to 4 _n also function as polling stations when the polling right is similarly given.

Upon receiving the polling signals P1 to Pn from the polling station P, the master stations 3 _{1 to} 3 _m and the slave stations 4 ₁ to 4 _n respond to the response signals A1 to A on both the up and down lines.
m and a1-an are sent out. The transmitted response signals A1 to Am and a1 to an are relayed by the master station and the slave stations and transmitted to the polling station P and other master stations.

The master stations 3 _{1 to} 3 _m send control information for the slave stations 4 ₁ to 4 _n together in the response signals A ₁ to Am,
Also, information in the system can be collected by receiving response signals from other master stations and slave stations.

The slave stations 4 ₁ to 4 _n send their own monitoring information when sending the response signals a ₁ to an, and receive not only the polling signal but also the control information from the master stations 3 _{1 to} 3 _m. The operation according to the received information is performed.

That is, the master stations 3 _{1 to} 3 _m can control the slave stations 4 ₁ to 4 _n regardless of the presence or absence of the polling right. Further, as described above, all the master stations and slave stations in the system can function as polling stations. This is the polling control unit 1 shown in FIG.
It is realized by having 0.

The polling control unit 10 comprises a receiving unit 11, a transmitting unit 12, a processing unit 13, a setting unit 14 and a timer 15. The receiving unit 11 receives a signal sent via the line and outputs it to the processing unit 13. The transmitter 12 sends a polling signal. The processing unit 13 performs processing for starting / stopping the polling operation of its own station. The setting unit 14 is set with a priority order for giving the polling right, and the timer 15 outputs a clock signal when the processing unit 13 performs various processes described later.

The start / stop processing of the polling operation of the own station by the processing unit 13 will be described with reference to the flowchart shown in FIG. First, as shown in step S1, the operation of intercepting the line for a certain period of time is performed. This is to receive the signal output from the receiving unit 11 for a certain period of time while referring to the clock signal of the timer 15, and to recognize the polling signal sent through the receiving unit 11 during this time together with the unique number of the station. It is a thing.

Next, as shown in step S2, it is determined whether another station is polling. this is,
When the polling signal from the other station is recognized in step S1, Yes is determined, and when it is not recognized, No is determined.

If the result of this determination is No, that is, if another station is performing a polling operation, then as shown in step S3, it is determined whether or not the own station is performing a polling operation. If the determination result is Yes, the process returns to step S1. If the determination result is No, neither the other station nor the local station is performing the polling operation, so the local station is activated for polling as shown in step S4.

On the other hand, if the result of the determination in step S2 is Yes, that is, if the polling signal from the other station is not recognized, it is determined in step S5 whether or not the own station is performing the polling operation. If the determination result is No, the process returns to step S1, and if Yes, as shown in step S6, it is determined whether or not the polling of the own station has the highest priority.

The determination as to whether or not this is the highest priority is made with reference to the priority order set in the setting unit 14. If the result of this determination is Yes, the process returns to step S1, and if No, to step S7. As shown, the polling operation is stopped and the process returns to step S1 to continue the above-described processing.

In such a polling system, the polling start / stop operation when a line failure occurs will be described with reference to the communication system shown in FIG. Reference numerals A, E, and G shown in FIG. 5 are master stations, and B, C, D, and F are slave stations, each connected by a full-duplex line. In addition, the priority order for acquiring the polling right is G-F-E-D-C-B-
A.

In such a configuration, it is assumed that the parent station A is currently performing polling. In this case, it is assumed that the line on one side for transmitting a signal from the slave station C to the slave station F indicated by an arrow Y1 in FIG. 6 fails.

In this case, the polling signal from the master station A does not reach the slave stations F and G. Since the slave station F and the master station G do not receive the polling signal even after a certain period of time, the master station G, which has a high priority, starts the polling.

This activation is performed by step S in FIG.
After the slave station F and the master station G perform the polling start in the processing of S1, S2, S3, S4, steps S1, S2, S5, S
Each priority is confirmed in the process of 6, and the slave station F has a low priority, so the polling is stopped in the process of step S7, and the master station G has a high priority. is there.

Immediately after the master station G polls, the slave stations B, C, D and the master station E collide with the polling signal with the master station A, and the polling signal cannot be received. After receiving the polling signal from G, the confirmation of the priority with the master station G is performed in the same manner as described above, and the polling operation is stopped.

In this state, since the polling station is only the master station G, the response signals of the slave stations B, C and D are not sent to the master station G, so that the master station G monitors only the slave station F, The master stations A and E monitor the other slave stations B, C, and D. This is because the master station can receive the response signal of the slave station and monitor it regardless of the polling right.

When the line failure is restored, the master station G remains the polling station and continues polling. Conventionally, when such a line failure occurs, since A of the polling station is fixed, F and G cannot receive the polling signal, and F and G cannot be monitored. The method can eliminate the drawback.

Next, in the case where the master station A is performing polling, the polling is activated / started when one side of the line for transmitting a signal from the slave station F to the slave station C indicated by an arrow Y2 in FIG. 7 fails. The stop operation will be described.

In this case, the polling signal from the master station A reaches all the slave stations B, C, D and F, so that A becomes the polling station as it is. This is step S in FIG.
1, S2, S3.

In this state, since the response signal of the slave station F does not reach the master stations A and E, the master stations A and E cannot monitor the slave station F. However, since the master station G can receive the response signals of all the slave stations B, C, D and F,
You can monitor them. Further, when the line failure is restored, the master station A continues polling as it is.

Conventionally, when such a line failure occurs, the polling station A cannot receive the response signals of F and G, and it is impossible to monitor F and G.
The polling method according to the embodiment can eliminate the drawback.

Next, when polling is being performed by the master station A, polling is started / stopped when the bidirectional line between the slave stations C and F indicated by arrows Y3 and 4 in FIG. 8 fails. The operation will be described.

In this case, since the polling signal from the master station A does not reach the slave stations F and G, the master station G having a high priority starts polling. Further, since the polling signal of the master station G which has become the polling station does not reach the master station A, the master station A continues the polling station.

In this case, the master station G polls and monitors the slave station F, and the master station A polls the slave stations B, C and D in the same manner as before the failure. Master station A,
Monitor at F.

In the prior art, when such a line failure occurred, the polling signal of A from the polling station could not be received by F and G, and F and G could not be monitored. The drawbacks can be eliminated.

When the line failure is restored, the master stations A and G confirm the priority, and the master station G becomes the polling station.

[0048]

As described above, according to the present invention,
Since a plurality of master stations that monitor slave stations can be installed and each master station or slave station can easily become a polling station, there is an effect that proper polling control can be performed when a communication line failure occurs.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of a communication system for explaining a polling method according to an exemplary embodiment of the present invention.

FIG. 3 is a block configuration diagram of a polling control unit for realizing a polling method according to an exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram of a polling start / stop operation of the polling control unit shown in FIG.

FIG. 5 is a configuration diagram of a communication system for explaining a polling operation by a polling method according to an exemplary embodiment of the present invention.

FIG. 6 is a first diagram showing a disconnection on one side of a full-duplex line in FIG.
FIG.

FIG. 7 is a second diagram showing one side disconnection of the full-duplex line in FIG.
FIG.

8 is a diagram showing all disconnections of the full-duplex line in FIG.

FIG. 9 is a configuration diagram of a communication system for explaining a polling method according to a conventional example.

[Explanation of symbols]

 21 polling control means 22 receiving means 23 other station polling recognition means 24 own station polling recognition means 25 setting means 26 priority recognition means 27 polling activation means 28 polling stop means

Claims (5)

[Claims] 1. A polling method in which a master station sequentially polls a plurality of slave stations and receives a response signal to monitor and control the plurality of slave stations. Polling control means for performing a polling operation by transmitting a polling signal from its own station to a plurality of master stations and a plurality of slave stations, and a receiving means for receiving a polling signal sent from another station. And another station polling recognition means for recognizing that another station is performing a polling operation when the polling signal is received by the receiving means, and its own station performing a polling operation when the polling control means operates. That the polling signal received by the receiving means is from which station the polling signal received by the receiving means is recognized. A priority recognition means for recognizing whether the priority is high or low for the recognized station and its own station by referring to the priority information, and another station and its own polling recognition means. When it is recognized that neither the other station nor the own station is performing the polling operation, the polling activation means for activating the polling operation of the polling control means and the other station and the own station polling recognition means And a polling stop means for stopping the polling operation of the polling control means when both the stations are recognized to perform the polling operation and the priority recognition means recognizes that the priority of the station is low. A polling method characterized by being equipped. 2. The reception when the other station polling control unit recognizes that the other station is not performing a polling operation and the local station polling control unit recognizes that the own station is performing a polling operation. 2. The polling system according to claim 1, wherein the means continues the operation of receiving the polling signal from another station. 3. When the other station polling control means recognizes that the other station is performing the polling operation and when the own station polling control means recognizes that the own station is not performing the polling operation, 2. The polling method according to claim 1, wherein the receiving means continues the operation of receiving a polling signal from another station. 4. The other station polling control unit recognizes that the other station is performing a polling operation, the own station polling control unit recognizes that the own station is performing a polling operation, and the priority is set. 2. The polling method according to claim 1, wherein when the recognizing means recognizes that the own station has a high priority, the receiving means continues the operation of receiving the polling signal from another station. 5. The plurality of slave stations are configured to control the plurality of slave stations by receiving the response signals from the plurality of master stations regardless of presence or absence of a polling right. The polling method according to any one of claims 1 to 4.