JPH04369734A - Duplex system - Google Patents

Abstract

PURPOSE:To eliminate a private line such as an alive line and to accurately discriminate the occurrence of abnormality in a communication network such as an inline network by recognizing the occurrence of abnormality in a main device when an auxiliary device does not receive an operation signal within prescribed time. CONSTITUTION:When a fault occurs in a master controller 2, it emits a master command at every prescribed time so that a backup controller 4 can recognize the occurrence of abnormality, and the command is receive by the backup controller 4 through the inline network 10. The backup controller 4 transmits a recognition signal as an auxiliary signal to respective terminal equipments 8 at every prescribed time and the terminal equipments 8 return a terminal signal to the backup controller 4 when the recognition signal is received. Thus, it is recognized that abnormality occurs in the master controller 2 only when the master command is not transmitted and when the terminal signal is received.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a duplex system,
In particular, it relates to an abnormality recognition system.

0002

2. Description of the Related Art As a duplex system, there is a POS controller duplex system as shown in FIG. The master controller 2 communicates with each terminal 8 via the inline network 10. Each terminal 8 sequentially transmits the number of products sold and other information.

[0003] Failures may occur in the master controller 2, and if such an abnormality occurs, each terminal 8
Communication becomes impossible, causing great confusion. Therefore, a backup controller 4 is provided to avoid such communication failure. This backup controller 4 means that when an abnormality occurs in the master controller 2, it immediately takes over the terminal 8 in place of the master controller 2.
It communicates with the computer and continues predetermined processing. Note that when the master controller 2 is operating normally, the backup controller 4 is disconnected from the inline network 10.

[0004] In order to recognize the occurrence of an abnormality in the master controller 2, a method is adopted in which a master command is sent from the master controller 2 to the backup controller 4 at regular intervals through an alive line 30. That is, if the master command is not sent for a predetermined period of time,
Backup controller 4 is master controller 2
It recognizes that an abnormality has occurred in the master controller 2, and immediately starts communication processing with each terminal in place of the master controller 2.

Note that a backup command is similarly transmitted from the backup controller 4 to the master controller 2 via the alive line 30. and,
When an abnormality such as a failure occurs in the backup controller 4, predetermined measures such as repair are immediately taken.

On the other hand, abnormalities such as failures may occur in the alive line 30 as well. Such line errors are recognized as follows. Communication between the master controller 2 and each terminal 8 is performed by a polling method. In other words, the master controller 2 sequentially sends messages to each terminal 8.
It inquires whether there is a communication request and receives a polling signal from the terminal 8. Then, data communication is performed with the terminal 8 that has requested communication. Using such polling-based communication, if a polling signal is not returned from the terminal 8, it is recognized that a line error has occurred, and necessary processing such as line repair is performed.

[0007]

[Problems to be Solved by the Invention] The conventional duplex system described above has the following problems. First, there is a problem in that in order to monitor the occurrence of an abnormality in the master controller 2, the alive line 30 must be provided as a dedicated line separately from the inline network 10.

[0008] In addition, since the line error check of the inline network 10 is determined based on the presence or absence of a polling reply signal from the terminal device 8, even if a polling signal is not sent due to, for example, a power outage of the terminal device 8, a line error may be detected. There is a problem with misidentification.

Therefore, the present invention eliminates the need for a dedicated line such as the alive line 30, and furthermore, the inline network 10
It is an object of the present invention to provide a redundant system that can accurately determine the occurrence of an abnormality in a communication network.

0010

[Means for Solving the Problems] A duplex system according to claim 1 includes: a main device that performs predetermined data processing regarding data transmitted via a communication network; a terminal device connected to the communication network;
If an error occurs in the main device while connected to a communication network,
In a duplex system equipped with an auxiliary device that processes data in place of the main device, the main device transmits an activation signal to the auxiliary device via a communication network at first predetermined intervals, and the auxiliary device (2) When the activation signal is not received within the predetermined time,
It is characterized by recognizing that an abnormality has occurred in the main device and starting data processing.

In the duplex system of claim 2, in the duplex system of claim 1, the auxiliary device transmits the auxiliary signal to the terminal via the communication network at third predetermined time intervals, and the terminal transmits the auxiliary signal. is characterized in that when it receives a terminal signal, it returns a terminal signal to the auxiliary device.

0012

In the duplex system of claim 1, the main device transmits an activation signal to the auxiliary device via the communication network at first predetermined time intervals. When the auxiliary device does not receive the activation signal within a second predetermined time period, it recognizes that an abnormality has occurred in the main device and starts data processing. Therefore, the auxiliary device can recognize the occurrence of an abnormality in the main device through the communication network.

In the duplex system of the second aspect, the auxiliary device further transmits the auxiliary signal to the terminal via the communication network at every third predetermined time. When the terminal receives the auxiliary signal, it returns the terminal signal to the auxiliary device. Therefore, if an abnormality occurs in the communication network, both the activation signal from the main device and the terminal signal from the terminal device will not be received by the auxiliary device. Further, if an abnormality occurs in the main device, the activation signal will not be received, but the terminal signal from the terminal will be received.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained based on the drawings. First, FIG. 1 shows an overall configuration diagram of a redundant POS controller system according to the present invention. An inline network 10 as a communication network is connected to the master controller 2, which is the main device. The master controller 2 performs data communication with each terminal 8 through this inline network 10.

A backup controller 4, which is an auxiliary device, is also connected to the inline network 10. When the master controller 2 becomes unable to communicate due to a failure etc., this backup controller 4
It performs communication processing with each terminal 8 in place of the master controller 2.

If a failure or the like occurs in the master controller 2, the master controller 2 transmits a master command at regular intervals so that the backup controller 4 can recognize the occurrence of this abnormality. This master command is then received by the backup controller 4 via the inline network 10 in the present invention. When the master command is not received for a predetermined period of time, the backup controller 4 recognizes that some kind of abnormality has occurred in the master controller 2, and immediately sends the instructions to each terminal 8.
Start communication processing with.

However, even if the master command is not received by the backup controller 4 for a predetermined period of time, it does not necessarily mean that an abnormality has occurred in the master controller 2. That is, inline network 1
It is also conceivable that the master command has not reached the backup controller 4 due to a line error of 0. In such cases, it is sufficient to perform line error processing.
There is no need to switch communication processing to the backup controller 4.

For this reason, the present invention adopts the following method. The backup controller 4 transmits a confirmation signal as an auxiliary signal to each terminal 8 at predetermined intervals. When the terminal device 8 receives this confirmation signal, it sends the terminal signal back to the backup controller 4. That is, under normal conditions, the backup controller 4 receives both the master command from the master controller 2 and the terminal signals from each terminal 8.

If a line error occurs in the inline network 10, both the master command and the terminal signal will not be received. In contrast,
If an abnormality occurs in the master controller 2, transmission of master commands is stopped, but terminal signals from each terminal 8 are received as usual. That is, it is recognized that an abnormality has occurred in the master controller 2 only when the master command is not transmitted and the terminal signal is received.

[0020] Also, from the backup controller 4,
A backup command is being sent through the inline network 10. If the master controller 2 does not receive this backup command for a predetermined period of time, it is recognized that an abnormality has occurred in the backup controller 4, and predetermined measures such as repair are taken.

Flowcharts of each process as described above are shown in FIGS. 2 and 3. First, specific processing operations of the master controller 2 will be explained. The master controller 2 performs processing as shown in FIG. 2 by interrupt processing. After starting the interrupt process, first, a master command is sent to the backup controller 4 (step S2). Next, it is determined whether a backup command from the backup controller 4 has been received within a predetermined time (step S4). If it is not received, it is recognized that the above problem has occurred in the backup controller 4, and processing to bring down the backup controller 4 is performed (step S6).

Next, the processing operations of the backup controller 4 will be explained based on the flowchart of FIG. The backup controller 4 does not perform controller business processing during normal operation of the POS controller system, and the master controller 2 performs business processing (step S1).
2). Then, the backup controller 4 sequentially transmits a confirmation signal to each terminal 8 at predetermined intervals (step S
13), and also sends a backup command to the master controller 2 (step S14). This backup command is taken into the master controller 2, and reception is determined in step S4 of FIG.

[0023] Next, the backup controller 4
It is determined whether a polling signal from the terminal has been received within a predetermined time (step S16). This polling signal is a response signal from the terminal corresponding to the confirmation signal transmitted in step S13. If a polling signal has been received, the process proceeds to step S22, where it is determined whether a master command from the master controller 2 has been received. This master command is step S in Figure 2.
This is the command sent by the master controller 2 in step 2.

If it is determined that the master command has been received, it is determined that there is no abnormality in both the master controller 2 and the inline network 10, and the processes from step S13 to step S22 are repeated. Step S2
If no master command is received in step 2, it is recognized that an abnormality has occurred in the master controller 2, and the controller waits.
(step S24), and the master controller 2
Starts controller business processing on behalf of (step S
26). The above is the process when the polling signal is received in step S16, but if the polling signal is not received, the process advances to step S18. Then, it is determined whether or not a master command has been received. When received, it is determined that there is no abnormality and the process returns to step S13. That is, since the master command from the master controller 2 has been received through the inline network 10, no abnormality has occurred. In this case, the reason why the polling signal was not received in step S16 is simply because the power of the terminal device 8 is stopped, and the master controller 2 determines that there is no problem with the business process and continues the process.

When the master command is not received in step S18, that is, when both the polling signal and the master command are not received, it is recognized that an abnormality has occurred in the inline network 10, and line error processing is performed (step S20).

Although the embodiments described above have been described using a POS controller duplex system as an example, the present invention is not limited to this, and can be applied to other duplex systems as well.

[0027]

Effect of the invention: In the duplex system of claim 1,
The auxiliary device can recognize the occurrence of an abnormality in the main device through the communication network. Therefore, there is no need to provide a dedicated line such as an alive line.

In the duplex system of the second aspect, if an abnormality occurs in the communication network, both the activation signal from the main device and the terminal signal from the terminal device will not be received by the auxiliary device. Therefore, the auxiliary device recognizes that an abnormality has occurred in the communication network only when it does not receive both the activation signal and the terminal signal. That is, even if the auxiliary device does not receive the terminal signal, it recognizes that no abnormality has occurred in the communication network as long as the activation signal is being transmitted. For this reason, even if a terminal signal is not transmitted due to power outage of the terminal, etc., there is no possibility of mistakenly identifying that an abnormality has occurred in the communication network.

Furthermore, in the duplex system of claim 2, when an abnormality occurs in the main device, the activation signal is not received, but the terminal signal from the terminal device is received. Therefore, it is possible to more accurately recognize the occurrence of an abnormality in the main device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of a POS controller duplication system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing processing operations of a master controller.

FIG. 3 is a flowchart showing processing operations of a backup controller.

FIG. 4 is a diagram showing an overall configuration diagram of a conventional POS controller duplication system.

[Explanation of symbols]

2... Master controller 4... Backup controller 8... Terminal

Claims (2)

[Claims] Claim 1: Regarding data transmitted via a communication network,
It is equipped with a main device that performs predetermined data processing, a terminal connected to a communication network, and an auxiliary device that is connected to the communication network and processes data in place of the main device if an abnormality occurs in the main device. In a duplex system, the main device transmits an activation signal to the auxiliary device via the communication network at a first predetermined time interval, and when the auxiliary device does not receive the activation signal within a second predetermined time period, the main device transmits an activation signal to the auxiliary device. A redundant system is characterized in that it recognizes that an abnormality has occurred and starts data processing. 2. In the duplex system of claim 1, the auxiliary device transmits the auxiliary signal to the terminal via the communication network at third predetermined intervals, and when the terminal receives the auxiliary signal, A redundant system characterized by sending terminal signals back to the device.