JPS64634Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a timing circuit used in a data recording device that records abnormalities in a system (for example, an electric power system).

[Conventional technology]

In a data recording device that records system abnormalities, it is necessary to record not only what kind of abnormality has occurred, but also the exact time when the abnormality occurred.

Therefore, a clock device is provided in the data recording device, and the details of the abnormality and the date and time of the abnormality occurrence are recorded together.

Naturally, the timekeeping device must be a so-called perpetual clock that corrects for large and small months, leap years, etc.

Further, the time measurement unit, especially in a data recording device for an electric power system, needs to be at least 0.01 seconds.

On the other hand, integrated circuits with the function of a perpetual clock are on the market, but unfortunately the minimum unit is one second.

Therefore, in the past, it was customary for manufacturers of data recording devices to combine an oscillator and a counter to create a perpetual clock circuit that clocks in units of 0.01 seconds.

[The problem that the idea aims to solve]

However, in the circuit configured in this way,
The circuit becomes complicated and the current consumption increases.
The drawback was that it required a large number of batteries for backup.

Therefore, the present invention aims to provide a perpetual clock that can measure time in units of 0.01 seconds using a simple circuit with low current consumption.

[Means to solve the problem]

This invention focuses on the fact that it is possible to use an integrated circuit with the function of a commercially available perpetual clock in units of 1 second or more. A frequency divider is provided, and the output signal of the second frequency divider is used to operate a perpetual clock circuit (commercially available) in units of seconds or more, and the output signal of the first frequency divider (for example, 0.01 seconds) is operated. By counting one pulse signal with a counter, time is measured in units of less than a second.

However, if this is done alone, over time, there is a possibility that the time measurement in units of seconds or more and the time measurement in units of less than seconds will deviate.

Therefore, we focused on the BUSY signal that is emitted every second by a commercially available perpetual clock circuit that measures time in units of seconds or more, and use this signal to clear the count value of the counter.

[Effect]

As a result, time measurement in units of less than a second is forcibly synchronized with time measurement in units of seconds every second, so that measurement in units of less than 1 second can be sufficiently reliable despite the simple circuit.

〔Example〕

A specific embodiment of the present invention will be explained with reference to the drawings.

1 is a reference frequency oscillator, which oscillates at a reference frequency of 3.2768 MHz.

The oscillation signal pulse is transmitted to the first frequency divider 2 and the second frequency divider 2.
is input to the frequency divider 3.

The first frequency divider 2 divides the oscillation signal pulse into
One pulse is output for every 32678 inputs.

In other words, it can be said to output one pulse every 0.01 seconds (100 hertz frequency signal).

The output pulse of the first frequency divider 2 is input to the less-than-1-second timer 4.

The less-than-one-second timer 4 is a so-called decimal counter, and counts the number of input pulses output from the first frequency divider 2.

In other words, the time will be measured in units of 0.01 seconds.

On the other hand, the second frequency divider 3 receives the oscillation signal pulse.
It outputs one pulse for every 100 inputs.

In other words, its output will be a frequency signal of 32.768 kilohertz.

This means that commercially available integrated circuits for watches are generally
It operates at 32.768 kilohertz, which is the frequency it is used for.

As mentioned above, even if there is an error in the 3.2768 MHz reference frequency, the 100 Hz and 32.768 kHz signals obtained by dividing the 3.2768 MHz reference frequency are compressed by each division ratio. This makes it an extremely accurate signal.

The output pulse of the second frequency divider 3 is input to the clock LSI 5.

The timing LSI 5 is a commercially available one, such as "MSM58321RS" manufactured by Oki Electric, and is designed to perform perpetual timekeeping in units of seconds or more by inputting a 32.768 kilohertz signal.

This timekeeping LSI 5 is BUSY in order to prevent timing from being accessed from the outside, for example, from a microprocessor (not shown) connected to the microprocessor bus 8, while the internal count value is changing. A signal called a signal is outputted to the microprocessor bus 8 via the interface unit 7 every second (however, here, the timing LSI
5 to the interface section 7 is not shown).

This BUSY signal is output exactly every second.

Therefore, it is a feature of the present invention that this BUSY signal is also input to the clear terminal of the less than one second timer 4.

As a result, the count value of the less-than-one-second timer 4 is forcibly synchronized (reset to zero) with the second-by-second timer every second.

The example above has been explained in which the frequency division ratio of the first frequency divider is set to 1/32678, but if it is set to 1/326780, time will be measured in units of 0.1 seconds.

At 1/163390, the signal becomes a 2Hz signal, which measures time in units of 0.5 seconds, but it is easy to understand that this circuit becomes meaningless if the frequency division ratio is higher than this.

[Effect of idea]

As described above, according to the present invention, even if an integrated circuit for a perpetual watch does not have the ability to measure time in units of less than a second, it is possible to measure time in units of less than a second with high reliability by simply adding a simple circuit. A circuit is obtained.

Therefore, the present invention is extremely useful in cases where time measurement in units of less than seconds is required, and where small-scale production is sufficient.

[Brief explanation of the drawing]

The figure shows an embodiment of the invention. 1... Reference frequency oscillator, 2... First frequency divider, 3... Second frequency divider, 4... Less than 1 second time measuring section, 5... ISI for clock, 6... BUSY signal, 7 …
...Interface section, 8...Microprocessor bus.

Claims (1)

[Claims for Utility Model Registration] A reference frequency oscillator; and an output signal of the reference frequency oscillator divided into two.
a first frequency divider that obtains a first frequency signal of Hz or higher; a second frequency divider that obtains a second frequency signal by dividing the output signal of the reference frequency oscillator; and a second frequency divider that obtains a second frequency signal. an integrated circuit for a perpetual clock that inputs a signal and measures time in units of seconds or more and emits a regular signal to the outside; and an integrated circuit that inputs the first frequency signal and counts the number of inputs; A clock circuit comprising: a counter that resets its count value to zero by the periodic signal emitted by the integrated circuit for use in the clock.