JPH01144749A - Communication device - Google Patents

Abstract

PURPOSE:To improve transmitting efficiency by continuously executing data transmission before the generation of abnormality when the abnormality is recovered and a time counting is not finished. CONSTITUTION:When the abnormality is generated in a main power source 5 during the transmission of data, which are stored in a memory 3, through a communicating interface 4 to an opponent station and the main power source 5 is recovered after the transmission can not executed, a CPU1 discriminates whether a timer 2 finishes the time counting or not. When the timer 2 finishes the time counting, the opponent station already goes to a condition that the data transmission is not received and on the other hand, when the timer 2 continues the time counting, the opponent station is in a condition that the data transmission is received. When the timer 2 finishes the time counting, the timer is started again by the CPU1 and the transmission is re-executed from the first step. Then, when the timer 2 does not finish the time counting, the data transmission before the abnormality of the main power source is continuously executed. Thus, the transmitting efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication device, and more particularly, to a communication device with improved abnormality recovery processing when an abnormality occurs in the power supply.

[Prior Art] In conventional communication devices, a predetermined time is determined between the communication devices in advance, data is transmitted only for a certain period of time from the start of data transmission, and when that time has elapsed, data is transmitted. Communication monitoring is being conducted to prevent data from being accepted. In such conventional communication equipment, if an abnormality occurs in the power supply during transmission, regardless of the state of the transmitting station,
Either continue the interrupted transmission, or
Return to the initial state and start transmission again from the beginning. FIG. 3 shows an example of a transmission sequence in a conventional communication device.

FIG. 3(a) shows a case where the transmission sequence is continued after an abnormality occurs in the power supply, and FIG. 3(b) shows a case where the sequence is reset after an abnormality occurs in the power supply. In FIGS. 3(a) and 3(b), data is being transmitted from station A to station B.

In FIG. 3(a), stations A and B start their respective timers at the same time as transmission begins.

Assume that after data (1) and (2) are transmitted from station A to station B, an abnormality occurs in the power supply of station A, and while the abnormality occurs in the power supply of station A, the timer of station B times out. When the power is restored, the A station continues the transmission sequence before the power failure and transmits the data (2), but the B station does not accept the transmitted data and notifies the A station of the error.

In FIG. 3(b), stations A and B start their respective timers at the start of transmission.

It is assumed that after data (1) and (2) are transmitted from station A to station B, an abnormality occurs in the power supply of station A, and the timer continues to measure time after the power supply is restored. After the power is restored at station A, station B notifies station A of the error in order to reset the sequence.

[Problems to be Solved by the Invention] As mentioned above, in conventional communication devices, when an abnormality occurs in one of the communication devices that are communicating, a shift in the transmission sequence occurs and the communication cannot be performed normally. There was a problem that transmission could not be performed.

Therefore, the main object of the present invention is to provide a communication device that can normally perform data transmission even if an abnormality occurs in the power supply during communication.

[Means for Solving the Problems] A communication device according to the present invention includes a timer that measures a predetermined time when data transmission with an external communication device starts, and a timer that measures a predetermined time when data transmission with an external communication device starts. a first power supply means for supplying power to the timekeeping means, a second power supply means provided separately from the first power supply means and capable of supplying power to the timekeeping means, and an external communication device. When the first power supply means recovers after an abnormality occurs in the first power supply means during data transmission between When it is determined that the time measurement by the time measurement means has ended, the data transmission with the external communication device is restarted from the beginning, and in response to the determination that the time measurement by the time measurement means has not ended. and transmission control means for controlling the first power supply means to continue data transmission before the occurrence of an abnormality.

[Operation] In the communication device according to the present invention, if an abnormality occurs in the first power supply means during data transmission, the time measurement means is supplied with power from the second power supply means to keep time. continue,
When the abnormality is recovered, it is determined whether or not the timekeeping by the timekeeping means has ended, and if the timekeeping has ended, the timekeeping is restarted and the data transmission is restarted from the beginning.
If the time measurement has not ended, the data transmission performed before the occurrence of the abnormality in the first power supply means is continued.

[Embodiments of the Invention] FIG. 2 is a schematic block diagram showing the electrical configuration of a communication device of the invention. In FIG. 2, the communication device of this embodiment is provided with a CPUI.

A timer 2, memory 3, and communication interface 4 are connected to the CPUI. The timer 2 measures a predetermined time. The timer of the other station is also set to the same time as this timer 2. The memory 3 includes a ROM that stores a CPU operating program as shown in FIG. 1, which will be described later, and a RAM that stores transmission data and the like. The communication interface 4 is for data transmission between the CPUI and the other station. CPUI mentioned above.

Timer 2. Memory 3 and communication interface 4 are supplied with power from main power supply 5 . Further, the timer 2 is supplied with power from the backup power supply 6 when an abnormality occurs in the main power supply 5. Note that the timer 2 may be constantly and stably supplied with power by a power source different from the main power source 5.

FIG. 1 is a flow diagram for explaining the operation of an embodiment of the present invention. Next, referring to Figures 1 and 2,
The operation of one embodiment of this invention will be explained.

When the CPUI starts transmission, it starts the timer 2 and transmits the data stored in the memory 3 to the other station via the communication interface 4, for example. After an abnormality occurs in the main power supply 5 during this transmission process and transmission cannot be performed, when the main power supply 5 is restored, the CP
The UI determines whether timer 2 has finished timing. Note that the timer 2 receives power from the backup power supply 6 and operates normally even when an abnormality occurs in the main power supply. Therefore, if timer 2 has finished counting, the other station is already in a state where it cannot accept data transmission, and on the other hand,
If timer 2 continues to measure time, the other station is ready to accept data transmission.

If timer 2 has finished counting, the CPUI restarts the timer and restarts the transmission from the beginning. Furthermore, if the timer 2 has not finished counting, the data transmission performed before the main power failure is continued.

[Effects of the Invention] As described above, according to the present invention, the first
If an abnormality occurs in the second power supply means, the timekeeping means is supplied with power from the second power supply means to continue measuring time, and when the abnormality is recovered, the timekeeping of the timekeeping means is terminated. If the time measurement has ended, data transmission is restarted from the beginning in order to restart the time measurement, and if the time measurement has not ended, it is determined that there is an abnormality in the first power supply means. Since the data transmission before the occurrence continues, even if an abnormality occurs in the external power supply, there will be no sequence deviation between communication stations, eliminating unnecessary data transmission and improving transmission efficiency. will improve.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram for explaining the operation of an embodiment of the present invention. FIG. 2 is a schematic block diagram showing the electrical configuration of an embodiment of the present invention. FIG. 3 is a diagram for explaining a conventional transmission sequence. In the figure, 1 is the CPU, 2 is the timer, 3 is the memory, and 4
5 indicates a communication interface, 5 indicates a main power supply, and 6 indicates a backup power supply. Patent applicant: Tateishi Electric Co., Ltd., 1.4+
1. Representative Patent Attorney Kube Fukami (・□ 1.・ (and 2 other people)
Figure 2

Claims (1)

[Scope of Claims] A communication device that performs data transmission with an external communication device capable of data transmission until a predetermined time elapses from the start of the transmission, wherein data transmission with the external communication device starts. When I did,
A clock means for measuring the predetermined time; a first power supply means for supplying power for data transmission between the external communication device; and a first power supply means provided separately from the first power supply means. , after an abnormality occurs in the first power supply means during data transmission between the second power supply means capable of supplying power to the time measurement means and the external communication device, the first power supply means When the power supply means is restored, a determining means determines whether or not the time counting by the time measuring means has ended; , the data transmission with the external communication device is restarted from the beginning, and the determination means determines that the time measurement of the time measurement means has not finished, and the first power supply means is abnormal. 1. A communication device comprising: a transmission control means for controlling to continue data transmission before an occurrence.