JPH0451796B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a system for automatically transmitting predetermined information from a large number of terminal devices to a center device via a telephone line. [Prior Art] For example, in an automatic gas meter reading system, a terminal device installed in each home automatically reads the gas meter at a predetermined date and time every month, and transmits the meter reading information to a central device via a telephone line. It is now possible to automatically notify the other party. On the other hand, since the center device in this type of system usually manages 10,000 or more terminal devices, if meter reading information from each terminal device is concentrated at one time, traffic will be confused. Therefore, in this type of system, the reporting times of meter reading information sent from terminal devices are set to be slightly shifted for each terminal device to avoid waiting time. [Problem to be solved by the invention] However, there is a limit to the accuracy of the timer of the terminal device, and the accuracy of the timer of the terminal device is limited, depending on the environment in which each device is installed.
Delays and advances occur independently for each terminal device. If this is left unaddressed, the actual reporting times of the terminal devices will overlap, making it impossible to ensure normal traffic, and the significance of setting different reporting times for each terminal device will be lost. [Means for Solving the Problems] The time adjustment method of the terminal device of the present invention has been made in view of the above problems, and the time adjustment method of the present invention is made in view of the above-mentioned problems. Then, time information is transmitted to the center device, and the center device detects the time when the predetermined information and time information are received based on its own timer device, and also combines the detected time and the time that is the content of the time information. After comparing, an end signal having a time length corresponding to the time difference is transmitted to the terminal device, and the terminal device corrects the time ticked by the timer means in the terminal device based on the time length of the received end signal. It is something. [Operation] Each time the terminal device reports predetermined information, the time of its own timer means is corrected based on the timer device in the center device. Therefore, the timer means in each terminal device always keeps time that almost coincides with the timer device in the center device. [Example] Hereinafter, the present invention will be described in detail with reference to Examples. FIG. 4 is a conceptual diagram showing the configuration of the automatic gas meter reading system. A terminal device 1 for automatic gas meter reading is installed in each household so as to be switchable with a telephone 2, and meter reading data from a gas meter reading means 3 can be transmitted to a central device 5 via a telephone line 4. There is. The center device 5 includes a center receiver 6 that automatically responds to a call from the terminal device 1 and takes in meter reading information, and a center receiver 6 that calculates gas charges based on the meter reading information transferred from the center receiver 6. The center computer 7 includes a center computer 7 that performs data processing and aggregation processing. FIG. 5 is a block diagram showing the configuration of the terminal device 1. As shown in FIG. The input terminal 11 of the terminal device 1 is a terminal for inputting a meter reading pulse from a gas meter (not shown), and the meter reading pulse is taken into the CPU 13 via the interface 12. CPU13 is
It is a microprocessor with a 4-bit configuration, and has the function of controlling the entire terminal device 1 in general, and also storing the reporting time set individually for each terminal device in the internal memory. The crystal oscillator 14 and frequency dividing circuit 15 are
Together with the counter provided in 13, it constitutes a timer means. That is, time information is created by a counter in the CPU 13 counting pulses from the frequency dividing circuit 15. The signal generation circuit 16 is a circuit that outputs meter reading information, time information, etc. in the form of a PB (push button) signal consisting of a combination of two types of frequency signals based on instructions from the CPU 13, and the signal detection circuit 17
is a circuit that detects a response signal and an end signal from the center device 5. Note that the significance of the response signal and end signal will be described later. The network control unit (NCU) 18 is a device that controls acquisition and release of telephone lines, and is configured to be applicable to either PB lines or DP lines. The switching means 19 is a means for selectively connecting the movable contact 19a to either the device-side fixed contact 19b or the telephone-side fixed contact 19c under the control of the CPU 13. The telephone line 4 is connected to the movable contact 19a.
The NCU 18 is connected to the fixed contact 19b on the device side, and furthermore,
The telephone 2 is connected to each of the fixed contacts 19c on the telephone side via an off-hook detection circuit 20. The movable contact 19a is usually the fixed contact 1 on the telephone side.
9c, and only when the terminal device 1 reports to the center device 5, the device side fixed contact 19
can be switched to b. The off-hook detection circuit 20 is a circuit that monitors the off-hook state of the telephone 2, and when the telephone 2 is off-hook, the off-hook signal is sent to the CPU.
13. FIG. 6 is a block diagram showing the configuration of the center receiver 6 provided in the center device 5. As shown in FIG. The center receiver 6 includes a control unit 31 and NCUs 32 and 33.
It consists of In this example, because it is simple,
Although the NCU is provided for only two lines, it is desirable to increase or decrease the NCU as appropriate depending on the number of terminal devices 1. For example, when managing 10,000 or more terminal devices 1, it is desirable to provide for about five lines. The control unit 31 is an 8-bit CPU 34, 16K
35 bytes of ROM and 48K bytes of RAM
It is equipped with 36. The clock IC 37 is a timer device that constantly supplies time information to the CPU 34. The serial interface 38 is a means for transmitting meter reading information etc. from the terminal device 1 to the center computer 7 via an RC232C cable. Further, external devices such as a buzzer and a printer are connected to the interface 39. The interfaces 40 and 41 are respectively
These are for connecting the NCUs 32 and 33 to the control section 31, and meter reading information, time information, etc. from the terminal device 1 are taken into the control section 31 via these interfaces 40 and 41. The control signal generation circuit 42 is a circuit that outputs a response signal and an end signal to the terminal device 1 connected via a telephone line based on instructions from the CPU 43. Next, the operation of the automatic gas meter reading system of this embodiment configured as described above will be explained using FIGS. 1 to 3. FIG. 1 is a sequence diagram showing the operating procedure of the system of this embodiment, FIG. 2 is a flowchart showing the operation of the terminal device 1, and FIG. 3 is a flowchart showing the operation of the center receiver 6. In the terminal device 1, at a preset notification time, that is, at a predetermined time on a predetermined day of every month, a notification process is performed on the center receiver 6 (step 201). The center receiver 6 is on standby for an incoming call from the terminal device 1 (step 301), and when an incoming call is received, the control signal generating circuit 42 sends out a 1650 Hz response signal for a predetermined period of time. In the terminal device 1, after receiving this response signal,
Data regarding meter reading information indicating the gas meter value at that time and time information indicating the time at that time is transmitted (step 202). After receiving data regarding meter reading information and time information (step 30), the center receiver 6 receives data related to meter reading information and time information.
2) The meter reading information is transferred to the center computer 7 via the serial interface 38. On the other hand, the time information is compared with a reference time created on the center receiver 6 side.
Here, the reference time refers to the actual time when the terminal device 1 transmitted the meter reading information and time information, that is, the actual time when the center device 5 received the meter reading information and time information, based on the time ticked by the clock IC 37. It is created each time meter reading information and time information is received. If both the timer means of the terminal device 1 and the clock IC 37 of the center receiver 6 keep perfectly accurate time, the content of the time information will match the reference time. As a result of this comparison, if the difference between the content of the time information and the reference time is ±15 seconds or more, the terminal device 1
It is determined that it is necessary to adjust the time of the timer means (step 304). The transmission of the correction time information from the center receiver 6 to the terminal device 1 is 1650, which means the end of signal exchange.
This is done using a Hz end signal. That is, the transmission time of the end signal and the correction time are correlated as shown in the table below, and if time correction is not necessary, an end signal with a width of 5 seconds is transmitted (step 305) and the time is adjusted. If correction is necessary, an end signal of a predetermined time width is transmitted (step 306).

〔Effect of the invention〕

As explained above, according to the time adjustment direction of the terminal device of the present invention, the time of the timer means in the terminal device is corrected with reference to the timer device in the center device every time the predetermined information is reported. Therefore,
The timer means of all the terminal devices always keep time almost coincident with the timer device in the center device. Therefore, if the reporting times set in each terminal device are set to be shifted from each other, the relative shift in reporting times between the terminal devices is always maintained. Therefore, there is no rush of reports from the terminal devices all at once, and normal traffic can be ensured.

[Brief explanation of the drawing]

Fig. 1 is a sequence diagram showing one embodiment of the present invention applied to an automatic gas meter reading system, Fig. 2 is a flowchart showing the operation of the terminal device in the system, and Fig. 3 is a flow chart showing the operation of the center receiver. 4 is a conceptual diagram showing the configuration of an automatic gas meter reading system to which this embodiment is applied, FIG. 5 is a block diagram of a terminal device in the system, and FIG. 6 is a block diagram of a center receiver. be. 1...Terminal device, 2...Telephone, 3...Gas detection means, 4...Telephone line, 5...Center device, 6
. . . Center receiver, 7 . . . Center computer.

Claims (1)

[Claims] 1. A reporting time is determined individually for each terminal device, and when each terminal device detects that the reporting time has arrived based on the output of its own timer means, it sends predetermined information to the telephone. In a system in which an end signal is automatically sent to a center device via a line, and the center device automatically sends an end signal notifying the end of signal exchange to a terminal device, the end signal is sent from the terminal device along with the predetermined information to the current time. The center device transmits time information as the content to the center device, detects the time when the center device receives the predetermined information and time information based on its own timer device, and also detects the detected time and the time that is the content of the time information. and then transmitting an end signal having a time length corresponding to the time difference to the terminal device, and correcting the time ticked by the timer means based on the time length of the end signal received at the terminal device. A method for adjusting the time of a terminal device.