JPS63659A - Multiple control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] In an online system that is a multiplex control system and is formed by connecting a higher-level device and a lower-level device, by providing a plurality of higher-level devices (controllers), the load on each controller is reduced and the load on each controller is reduced. This is designed to provide backup in case one of the controllers goes down.

[Industrial Application Field] The present invention provides a #IIJ terminal device in a PoS system, etc.
The present invention relates to a 1ull control system, and more specifically, to a 5-channel control system in which the reliability of the online system is improved by using a configuration in which controllers for i+l control of terminals are used in multiple ways.

In recent years, computer-based distribution management systems have come into use in the distribution industry (retail and wholesale). As this type of distribution management system, for example, a POS system (point of sale system) is well known. The POS system is a high-level device called PO
By combining the S controller and multiple lower-level terminals (for example, registers), the barcode attached to the product is read by a barcode reader attached to the register, and the read information is processed by the POS controller. is POS
This system sends information via a controller to a central host computer via a communication line to manage product inventory.

[Prior Art J] FIG. 3 is a diagram showing an example of the configuration of a conventional online system of this type. In J3 shown in the figure, 1 is a controller (control unit @) that controls lower-level terminals, 2 is a plurality of terminals connected to the controller 1 through a line, such as a register, and 3 is connected to these terminals. This is a barcode reader for reading barcodes attached to products.

Reference numeral 4 denotes a file memory in which data such as product names, prices, etc. are stored. In the system configured as described above, the barcode attached to the product is read by the barcode reader 3 for each register, and is sent from the register 2 to the controller 1 via a line. The controller 1 searches data such as product name and price stored in the file memory 4 from the barcode data sent (P
LU-Price Lookup). Next, the controller 1 notifies the searched product name and price to the lower terminal 811 (register) 2 via the line, and performs customer processing.

[Problems to be Solved by the Invention] The conventional online system has a configuration in which a plurality of terminals are connected to one controller, as described with reference to FIG. Therefore, when the number of terminals or items to be processed increases, the burden on the controller increases, and if the controller goes down, the entire system goes down. There is also a known technology in which the controller is a dual device, and when a failure occurs on the - side, the normal controller monitors it and controls switching, but the load on the controller for switching control is large, and the terminals that can be connected are This has the disadvantage that the number is limited.

The present invention has been made in view of these points, and
It is an object of the present invention to provide an Iζ multiplex control system in which there is no need to place a load on the controller itself for line switching and the entire system does not go down even if the controller goes down.

[Means for Solving the Problems] FIG. 1 is a block diagram of the principle of the multiplex control system of the present invention. In the figure, 11.11' indicates a pair of controllers, and 12 indicates these controllers 11.1.
A line switching machine 13.13' connected to the lines L+ and L+' from 1' and performing switching operations for these lines is a plurality of terminals connected to the line switching 112. Terminal 1
For example, the register mentioned above is used as i113.13'. In addition, the line switching device 12 includes a fault detection means 2.
3 are provided, and this means 23 detects the presence or absence of a fault in the controller 11.11'.

[Operation] In the system configured as described above, during normal operation, the controller 11 and the terminal 13 are connected, and the controller 11' and the terminal 13' are connected, respectively.
The barcode data read by the terminal 13.13' is sent to the controller 11.1 via lines L+ and Ll', respectively.
1' is returned. Here, when the controller 11 goes down, the line switching device 12 detects the down state of the controller 11 using the failure detection means 23, and switches the lower terminal 13 to a controller 11' of another system. As a result, all the lower terminals 1113.13' operate normally and the system does not go down. The above backup operation is the same even when the controller 11' goes down, and the controller 11 backs up the lower terminal 11113' instead.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention. Components that are the same as those in FIG. 1 are designated by the same reference numerals. In the figure, 21.22 is the controller 11.1, respectively.
1' and connected files and memory, 23 is line L1
and a down detection circuit that detects when the controller 11 goes down (same as the failure detection circuit 23 described above), and 23' is a circuit aL.
This is a down detection circuit that is connected to the controller 11' and detects when the controller 11' goes down. sw and sw' are changeover switches connected to the lines C1 and 11', respectively, sw is connected to the terminal 13, and SW' is connected to the terminal 13'. And these changeover switches sw.

Switching of SW' is controlled by down detection circuits 23 and 23'. The down detection circuit 23, 23' and the changeover switches sw and sw' constitute a line switching unit 12. The operation of the device configured as described above will be explained as follows.

Normal operating state, i.e. upper controller 11°11'
When all are operating normally, selector switch s
, sw' are each connected to the a contact side. Therefore, in the normal operating state, the controller 11 and the terminal 13 are connected to each other, and each constitutes an information transmission system.
, 13' are sent to controllers 11, 11' via lines LI+1, +, respectively. The controller 11.11' stores the file memory 21.2 based on the sent barcode data.
2, and performs predetermined inventory management processing.

Now, assume that the controller 11 is down for some reason. When the down detection circuit 23 detects that the controller 11 has gone down, it switches the changeover switch SW from the A contact side to the B contact side. A method for detecting whether the host controller 11 is down is as follows.
For example, a method of monitoring the status constantly output from the controller 11 or a method using a watchdog timer can be considered. In the former case, the down state can be detected based on the status from the controller 11,
In the latter case, the down state can be detected by the overflow of the watchdog tie 7.

By switching the changeover switch SW to the b contact side, the terminal device 13 is switched to a host device in another system, that is, the controller 1.
It is under the control of 1'. As a result, the controller 11
Although the negative 1 of ' increases and the tF boat level of terminals 13 and 13' decreases, all terminals can be used.

In the above description, J3 has been described using an example of a duplex configuration in which the number of host controllers is two, but the present invention is not limited to this. Con]・Number of rollers is 3
It is possible to have a multiplexed configuration with more than one. In this case, when one of the upper controllers goes down, it would be helpful to set the priority and memorize in advance which other upper controller the lower terminals connected to that controller should be connected to. stomach. If such a multiplexed configuration is adopted, even if an accident occurs in which two higher-level controllers go down at the same time, the lower-level terminals will be backed up, and the reliability of the system will be greatly improved.

[Effects of the Invention] As explained in detail above, according to the present invention, a plurality of higher-level controllers can be disconnected once! By adopting a multiplexed configuration in which lower-level terminals are connected via II machines, it is possible to prevent the entire system from going down even if the upper-level controller goes down.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of a multiplex control system according to the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing an example of the conventional configuration of an online system. In Figures 1 and 2, 11.11' is the controller, 12 is the line switch, 13.13' is the 9-product terminal, 21.22 is the file memory, 23.23' is the down detection circuit, L+, L+' is a line. Figure 1 is a block diagram of the principle of the present invention. Figure 2 is a block diagram showing the mechanism of the present invention.

Claims (1)

[Claims] A plurality of controllers (11), (11'), and a line switching machine (12) for these controllers (11), (11').
A plurality of terminals (13), (13'
) and a fault detection means (23) provided in the line switching machine (12) to detect a fault in the controller, and when it is detected that either the controller (11) or (11') is down, the A multiplex control system characterized in that a terminal device connected to a down controller is connected to a controller of another system by a line switching device (12).