JPH0415794A - Transaction processor with transmission fault preventing function - Google Patents

Abstract

PURPOSE:To prevent system down from occurring when a fault occurs by monitoring the operation of a transmission control means which controls the operation of a transmission/reception part, and disconnecting the transmission/ reception part from a transmission control means. CONSTITUTION:When abnormality is found out in either a main CPU 2 or a sub CPU 3 for transmission, the output of a refresh pulse is stopped. When the input of the refresh pulse is interrupted for one or more seconds, the output part of a watchdog timer 4 is turned off, which sets a switching element 7 in a cutoff state. Therefore, a transceiver 6 is disconnected from the transmis sion line 12. Consequently, no abnormal signal is outputted to the transmission line 12, and the transmission of another POS terminal 1 can be prevented disturbed. Thereby, the system down can be prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a transaction processing device that is branch-connected to a transmission line and performs transmission via the transmission line, and particularly relates to a transaction processing device that has a transmission failure function.

[Prior art] Fig. 4 shows a conventional PO3 (Point of sale)
s) It is a schematic block diagram showing the configuration of the system. Fourth
As shown in the figure, a plurality of PO3 terminals 21a to 21n are installed in supermarkets, department stores, and the like. P
The O3 terminal is used to register price data and product codes for products purchased by customers.

Each PO8 terminal is branch-connected to the transmission line 22. A store controller 23 is connected to the end of the transmission line 22 for controlling the operation of each PO8 terminal and for collecting and editing data from each PO8 terminal. A transmission system in which a plurality of terminal devices are connected to one transmission line in this way is called a multi-drop system.

By the way, in the multi-drop transmission system described above, in order to prevent data transmission from a plurality of PO8 terminals at the same time, line setting is normally performed using a polling system. In other words, the master station (store controller) in turn invites the slave stations (POS terminals) to send information messages, and when the slave stations are ready to send the information messages, the slave stations can start transmitting information. .

[Problems to be Solved by the Invention] Such a multi-drop transmission method is a problem that occurs when a failure occurs in one PO8 terminal of the POS system and the enable gate of the driver provided in that PO8 terminal becomes active. If this occurs, an abnormal signal will be continuously output to the transmission line, and other PO8 terminals will no longer send information messages, resulting in a system failure.

Although not shown in Figure 4, there is also a P
In addition to the O8 terminal, there is also a CA for credit processing.
T (credit authorization)
terminal) or other input/output terminals may be connected. Among such terminals, there are terminals (hereinafter referred to as A terminals) that use the chassis or frame of the terminal body as the ground wire of the transceiver, and terminals whose transceiver ground wire is grounded separately from the chassis (hereinafter referred to as A terminals).
Terminal B) also exists. FIG. 5 shows a state in which terminal A and terminal B are connected via a transmission line. In FIG. 5, terminal 31 is a B terminal, and terminal 32 is an A terminal. Referring to FIG. 5, if there is a short circuit between the secondary side voltage (+24 V) terminal of the B terminal 31 and the chassis, the B terminal chassis 311 -> ground wire 33 - the A terminal chassis 321 - the ground wire. 322 → A terminal transceiver 3
23→transmission line 34→B terminal transceiver 313→ground wire 312, and a large amount of current flows through the transceivers of both terminals. As a result, the elements constituting the transceiver are destroyed, leading to system down.

As mentioned above, when a system goes down, it is difficult to determine which terminal has failed, and it takes a long time to remove or replace the faulty terminal and restore the system.

Therefore, the main object of the present invention is to provide a transaction processing device having a failure prevention function that does not cause a system down even if a failure occurs and makes it easy to discover the failure.

[Means for Solving the Problems] The present invention provides a transaction processing device which is branch-connected to a transmission line and transmits data via the transmission line, and which is insulated to prevent abnormal current from flowing in from the outside. a transmitter/receiver for transmitting and receiving data, a transmission control means for controlling the operation of the transmitter/receiver, a monitoring means for monitoring the operation of the transmission control means, and a transmitter/receiver for controlling the transmitter/receiver when an abnormality is discovered by the monitoring means. and a transmission line, and a notification means for notifying the occurrence of an abnormality when an abnormality is detected by the monitoring means.

[Function] In the present invention, the transmitting/receiving section for transmitting and receiving data via the transmission line is insulated to prevent abnormal current from flowing in from the outside, and the elements constituting the transmitting/receiving section are protected from excessive voltage or current. will not be destroyed. It also monitors the operation of the transmission control means that controls the operation of the transmitter and receiver,
If a failure occurs in the transmission control means and the operation becomes abnormal, the transmitting/receiving unit and the transmission line are cut off, so if a failure occurs, other devices connected to the transmission line No abnormal signals are supplied to the transaction processing device. Furthermore, since the occurrence of an abnormality is notified, it becomes possible to easily discover and remove or replace a faulty transaction processing device.

[Embodiments of the Invention] Hereinafter, a PO8 terminal will be described as a transaction processing device having a transmission failure prevention function according to an embodiment of the present invention, but the present invention is not limited to this. I would like to point out in advance that it can be adapted to anything.

FIG. 1 is a schematic block diagram showing a PoS system configured by branching and connecting PO8 terminals according to an embodiment of the present invention. Referring to FIG. 1, the POS system includes transmission line 12.
It includes, for example, 32 PO8 terminals 1 branch-connected to. Although not shown, a store controller and a host computer are connected to the transmission line 12.

The PO8 terminal 1 includes a transceiver section 5 and a sub-CP for transmission.
U3, peripheral interface 9, ROM10, and R
It includes an AMII, a main CPU 2, a watchdog timer (WDT in the figure) 4, and a display section 8.

The transceiver part 5 performs transmission and reception via the transmission line 12, and includes a transceiver 6 and a switch element 7. The transmission sub-CPU 3 controls the operation of the transceiver 5. When a polling signal is received from the controller connected to the transmission line 12, if there is data to be transmitted, the transmission sub CPU is used to enable data transmission from the PO8 terminal 1.
3 outputs a gate enable signal to the transceiver 6. Transmission data is output from the transmission sub-CPL; 3 to the transmission line 12 via the transceiver 6. Received data is received on the opposite route to this route.

The peripheral interface 9 is an interface for inputting and outputting between the transmission sub CPU 3 and the main CPU 2. The ROM 10 stores an operating program for the main CPU 2. The RAM 1l temporarily stores transmitted data and received data. Main CP
U2 is the peripheral interface 9. ROM10. RAMI
It controls the operation of I. The watchdog timer 4 is for monitoring the operations of the main CPU 2 and the transmission sub CPU 3. Display section 8 is the main CPU
2 or the operation of the transmission sub CPU 3 becomes abnormal, it is used to notify the abnormal state, for example, L
Consists of ED.

FIG. 2 is a schematic block diagram showing the configuration of a part of the transceiver of the PO3 terminal shown in FIG. 1. Next, the insulation structure of the transceiver section will be explained with reference to FIG. The transceiver 6 of the transceiver unit 5 includes a driver 61 for transmission and a receiver 62 for reception. The switch element 7 is used to cut off the transceiver 6 and the transmission line 12 when an abnormality occurs in the main CPU 2 or the transmission sub-CPU 3. As the switch element, one in which the contact part 71 is completely insulated from the drive part 72 is used. The switch element 7 may be composed of a reed relay or an optical MO8FET relay.

The transceiver section 5 includes an isolated DC/DC converter 51. Includes photocouplers 52, 53 and 54. Isolated DC/DCC/type-ta 51 is the power supply Vc of PO8 terminal 1
This is for supplying power to the transceiver 6, which is insulated from the power source c. The photocouplers 52, 53, and 54 are used to temporarily convert electrical signals exchanged between the transmission sub-CPU 3 and the transceiver 6 into optical signals. A gate enable signal for the driver 61 is applied to the photocoupler 52 from the transmission sub-CPU 3 . Transmission data is given to the photocoupler 53 from the transmission sub-CPU 3. Transmission data is sent from the driver 61 to the transmission line 12
is output to. Received data from the receiver 62 is given to the photocoupler 53 and output from the photocoupler 54 to the transmission sub-CPU 3. In this way, the electric signal is converted into an optical signal during transmission, and then converted into an electric signal, so that the transceiver unit 5 is connected to the transmission sub CPU 3.
electrically isolated from

As mentioned above, the power supply system for the transceiver is an isolated DC
The transceiver section 5 is connected to the primary power supply of the PO8 terminal 1 by using a /DCC/ type-ta, a photocoupler for the signal system, and completely insulated switching elements such as the contact section 71 and the drive section 72. , completely isolated from secondary power sources and yarns. Therefore, no excessive current will flow into the transceiver unit 5 from the power supply line or the ground line, and no excessive voltage will be applied. The above configuration prevents the elements constituting the transceiver section 5 from being destroyed.

FIG. 3 is a diagram showing output waveforms of the transmission sub-CPU and watchdog timer shown in FIG. 1.

Next, with reference to FIG. 3, the control operation of the transmission line cutoff switch element will be described.

The transmission sub-CPU 3 activates the watchdog timer 4 to control the switch element 7.

In performing this control, the transmission sub-CPU 3
The operation of the PU2 and the operation of the transmission sub CPUB itself are monitored. The former type of monitoring is performed by monitoring the timer output of the main CPU 2, and if a pulse signal is supplied at a predetermined interval, it is determined to be normal; otherwise, it is determined to be abnormal. The latter monitoring is similarly performed by monitoring the timer output of the transmission sub CPU 3.

When both the main CPU 2 and the transmission sub CPU 3 operate normally, the transmission sub CPU 3 operates as shown in FIG.
) is output to the watchdog timer 4 with a period of 20m5. Main CPU2
Alternatively, when an abnormality is found in any of the transmission sub-CPUs 3, the output of the riff 1 notification signal is stopped. In the watched timer 4, when the input of the refresh pulse is interrupted for one second or more, for example, the output section is turned off as shown in FIG. 3(b), and the switch element 7 is cut off. This disconnects the transceiver 6 from the transmission line 12. Therefore, transmission line 12
No abnormal signal is output to the terminal, and transmission from other PO8 terminals is not obstructed. If a type in which the output section is held is used as the above-mentioned watchdog timer 4, once the switch element 7 is cut off, the contact 71 will remain in the open state, and the occurrence of system down can be reliably prevented. Ru.

Additionally, as shown in Figure 3(b), the switch is in the cut-off state and the LED on the display unit 8 lights up due to the input/output from the watchdog timer 4, indicating that an abnormality has occurred in the PoS terminal. Let me know. By attaching this LED in a position where the operator can easily see it, it becomes possible to easily discover a PoS terminal in which a failure has occurred, and the time required for replacement etc. can be shortened.

[Effects of the Invention] As described above, according to the present invention, the transmitting/receiving section for transmitting and receiving via the transmission line is insulated to prevent abnormal current from flowing from the outside, so that the elements constituting the transmitting/receiving section are Destruction due to excessive voltage or excessive current is prevented.

The system also monitors the operation of the transmission control means that controls the operation of the transmitter/receiver, and if a failure occurs in the transmission control means and the operation becomes abnormal, the transmitter/receiver and the transmission line are cut off. Therefore, if a failure occurs, no abnormal signal will be supplied to other transaction processing devices connected to the transmission line. Therefore, even if a failure occurs in the terminals that make up the transaction processing system, the system will not go down.

Furthermore, since the occurrence of an abnormality is notified, it becomes easy to discover the faulty transaction device and remove or replace it.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing a POS system configured by branching and connecting PoS terminals according to an embodiment of the present invention. FIG. 2 is a schematic block diagram showing the configuration of a transceiver section of the PoS terminal shown in FIG. 1. FIG. 3 is a diagram showing output waveforms of the transmission sub-CPU and watchdog timer shown in FIG. 1. FIG. 4 is a schematic block diagram showing the configuration of a conventional POS system. FIG. 5 is a diagram for proving the failure state that occurs in the conventional POS system shown in FIG. 4. In the figure, 1 is a PoS terminal, 2 is a main CPU, 3 is a transmission sub-CPU, 4 is a watchdog timer, 5 is an isolated transceiver section, 6 is a transceiver, 7 is a switch element, 8 is a display section, and 12 is a Shows transmission line.

Claims (1)

[Claims] In a transaction processing device that is branch-connected to a transmission line and transmits data via the transmission line, the transaction processing device is insulated to prevent abnormal current from flowing in from the outside and for transmitting and receiving data via the transmission line. a transmission/reception section; a transmission control means for controlling the operation of the transmission/reception section; a monitoring means for monitoring the operation of the transmission control means; and when an abnormality is discovered by the monitoring means, the transmission/reception section A transaction processing device having a transmission failure prevention function, comprising: switching means for cutting off the transmission line; and reporting means for notifying the occurrence of an abnormality when an abnormality is discovered by the monitoring means.