JPH0821884A - Clock device - Google Patents

Abstract

PURPOSE:To provide a clock device capable of preventing the advance of the clock when noise is mixed into a power source by shaping the waveform of the power voltage, outputting the pulses corresponding to the power frequency, and providing a back-up clock ticking the time based on an oscillator. CONSTITUTION:The voltage cycle range corresponding to the power frequency is set in advance. When pulses are generated from a wave-form shaping circuit 2A at the reference cycle, the pulses are counted to tick the time, and the time is written into a crystal clock 3 at a constant cycle, e.g. at every minute. When the pulse interval becomes longer than the reference time, it is judged that a power stoppage or a momentary stoppage occurs, and the time is ticked by the crystal clock 3 for a fixed period, e.g. until 00 second of the next minute of the crystal watch 3 or until 00 second of the next minute after the electric power is recovered. When pulses are generated at the cycle shorter than the reference cycle, it is considered that noise is mixed, the time is likewise ticked by the crystal clock 3 until 00 second of the next minute, and the clock is switched to a back-up clock synchronized with the power frequency after 00 second of the minute at the reference cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timepiece device used for an electronic watt hour meter, an electronic maximum demand watt meter, or a composite instrument of these.

[0002]

2. Description of the Related Art The structure of a conventional timepiece device will be described with reference to the block diagram shown in FIG. The timepiece device of FIG. 4 has a power supply voltage terminal 1 connected to a commercial power supply (not shown), a waveform shaping circuit 2 including a noise filter connected to the power supply voltage terminal 1, a quartz clock 3, a waveform shaping circuit 2 and It is composed of a microcomputer 4 connected to the quartz clock 3, a display 5 connected to the microcomputer 4, and a power supply circuit 6 such as a battery for supplying power to each circuit. 4 shows the timepiece device portion of the electronic watt-hour meter. The power supply current terminal 7 and the input side are connected to the power supply voltage terminal 1 and the power supply current terminal 7, and the output side is connected to the microcomputer 4. The connected electric energy frequency conversion circuit 8 is also shown.

Next, the operation of the conventional timepiece device will be described. The power supply synchronous clock based on the power supply frequency is accurate in the long term because the frequency difference is corrected by the electric power company throughout the year. The waveform shaping circuit 2
The power supply voltage is waveform-shaped and a pulse proportional to the power supply frequency is output to the microcomputer 4. The microcomputer 4 counts the input pulses and cycles the time as a power supply synchronized clock. Further, the time is displayed on the display unit 5.

In such a configuration, if noise is mixed in the power supply, even if the waveform shaping circuit 2 has a noise filter, it cannot be completely removed, and the power supply synchronous clock advances. It should be noted that at the time of power failure, the microcomputer 4 switches to the time of the quartz clock 3. On the other hand, the power amount frequency conversion circuit 8 multiplies the power supply voltage and the current to obtain the power amount, converts the power amount into a frequency, and outputs the frequency to the microcomputer 4. Microcomputer 4
Is designed to integrate input frequencies and calculate integrated electric energy.

[0005]

The conventional timepiece device described above has a problem that the power supply synchronized timepiece advances when noise is mixed in the power supply. The present invention solves the above problems, and an object thereof is to obtain a timepiece device that can prevent the timepiece from advancing when noise is mixed in the power supply.

[0006]

The timepiece device according to the present invention comprises the following means. (1) A waveform shaping circuit that shapes the waveform of the power supply voltage and outputs a pulse corresponding to the power supply frequency. (2) A backup clock that keeps time based on an oscillator. (3) Counting the pulses to engrave the time as a power supply synchronized clock, adjust the time of the backup clock to the time of the power supply cycle clock at regular intervals, and if the pulse cycle is shorter than the reference power supply cycle, Central processing circuit that switches to the time of the backup clock.

[0007]

In the present invention, by the waveform shaping circuit,
The power supply voltage is waveform-shaped and a pulse corresponding to the power supply frequency is output. In addition, the central processing circuit counts the above-mentioned pulses to engrave the time as a power supply synchronized clock, adjusts the time of the backup timepiece to the time of the power supply synchronized timepiece at regular intervals, and makes the period of the pulse the reference power supply. If it is shorter than the cycle, the time is switched to the time of the backup clock.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the power supply voltage terminal 1, the crystal timepiece 3, the display 5 to the power amount frequency conversion circuit 8 are exactly the same as those of the conventional device. In the embodiment of the present invention shown in FIG. 1, the waveform shaping circuit 2 and the microcomputer 4 of the conventional device are replaced with a waveform shaping circuit 2A having no noise filter and a microcomputer 4A having a new function. By the way, the backup timepiece of the present invention is the crystal timepiece 3 in the above-described embodiment of the present invention, and the central processing circuit is the microcomputer 4A.

Next, the operation of the apparatus of the above embodiment will be described with reference to the waveform chart of FIG. 2 and the flow chart of FIG. In FIG. 2, the power supply is normal in the period A, the power is cut in the period B, the power is restored in the period C, noise is mixed in the period D, and the state E is normal.

In step 10 of FIG. 3, the microcomputer 4A sets the time mode to the power cycle clock. In step 11, the microcomputer 4A counts the pulses from the waveform shaping circuit 2A and sets the waveform shaping circuit in a voltage period range (reference period) preset corresponding to the frequency of the power source, for example, 47.5 to 52.5 Hz for 50 Hz. Determine if 2A is pulsing. Figure 2
When the pulse generation is longer than the reference period, as indicated by the period B, the power failure or the instantaneous power failure is determined and the process proceeds to step 12. If not, proceed to Step 14. In steps 12 to 13, the time mode is set to the crystal timepiece 3, and the time is set by the crystal timepiece 3 until the next minute 00 seconds after the power is restored, for example, as indicated by the period C in FIG. Then, return to step 10. In step 14, as shown in period D of FIG.
If the pulse generation is shorter than the reference period, it is determined that noise is included and the process proceeds to step 15. If not, proceed to step 17. In steps 15 to 16, the time mode is set to the crystal timepiece 3, and the time is set by the crystal timepiece 3 until the next minute 00 seconds after the pulse generation returns to the reference period, as shown in period E of FIG. Then, return to step 10. In steps 17 to 18, the time of the power supply synchronized clock is written in the quartz clock 3 at regular intervals, for example, every one minute. That is, the time of the quartz clock 3 is corrected.

In one embodiment of the present invention, as described above, the voltage cycle range corresponding to the frequency of the power supply is set in advance, and when the pulse is generated from the waveform shaping circuit 2A at the reference cycle, it is set. While counting and engraving the time, the time is written in the quartz timepiece 3 at regular intervals, for example, every one minute. When the pulse generation is longer than the reference period, it is determined that there is a power failure or an instantaneous power failure, and the time is kept by the quartz clock 3 until a certain time, for example, the next 00 minutes or the next minute 00 seconds after the power is restored. If the pulse generation is shorter than the reference period, it is considered that noise is mixed and the time is ticked by the quartz clock 3 until the next minute 00 seconds in the same manner as above, and when the reference period is reached (if it becomes the correct period) Switch from 00 seconds to a clock synchronized with the power supply frequency.

Therefore, parts such as a noise filter for preventing noise from being mixed into the waveform shaping circuit 2A can be omitted, and a stable power supply frequency is used when there is a voltage to switch to the quartz clock 3 when a power failure or power failure occurs. This has the effect of eliminating the drawbacks of the timepiece 3 only. By the way, in the above description, the case of using for an electronic watt-hour meter was described, but it goes without saying that it can also be used for other complex devices.

[0013]

As described above, the present invention provides a waveform shaping circuit for shaping the waveform of the power supply voltage and outputting a pulse corresponding to the power supply frequency, a backup timepiece that keeps time based on an oscillator, and the pulse. The clock is counted as a power synchronized clock, and the time of the backup clock is adjusted to the time of the power synchronized clock at regular intervals, and when the pulse cycle is shorter than the reference power cycle, the time of the backup clock is adjusted. Since the central processing unit for switching is provided, it is possible to prevent the timepiece from advancing when noise is mixed in the power supply.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a waveform diagram showing output pulses of the waveform shaping circuit according to the embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional timepiece device.

[Explanation of symbols]

 1 Power supply voltage terminal 2A Waveform shaping circuit 3 Quartz watch 4A Microcomputer 5 Display

Front Page Continuation (72) Inventor Osamu Ikeda 1-8 Midoricho, Fukuyama-shi, Hiroshima Mitsubishi Electric Corporation Fukuyama Works

Claims (1)

[Claims] 1. A waveform shaping circuit that shapes the waveform of a power supply voltage and outputs a pulse corresponding to the power supply frequency, a backup clock that ticks the time based on an oscillator, and a clock that counts the pulses to set the time as a power synchronized clock. A central arithmetic processing circuit that adjusts the time of the backup clock to the time of the power supply synchronous clock at regular intervals and switches to the time of the backup clock when the pulse cycle is shorter than the reference power supply cycle. Characteristic clock device.