JP6869058B2 - Time output device and time output method - Google Patents

Description

The present invention relates to a time output device and a time output method.

In recent years, a time server that acquires Japan Standard Time, stamps the time based on the acquired standard time, and distributes the stamped time to devices on the network with high accuracy has been used. In such a time server, time information distributed from a time source such as a time supply system by a telephone line is stamped with a high-precision, high-resolution system clock, and an auxiliary clock is used at a predetermined timing. Write to RTC (Real Time Clock). Then, for example, when the power of the time server is turned off during maintenance, the system clock is extinguished. Therefore, when the power is turned on next time, the time information from the RTC is read into the system clock.

In the device that holds the time in this way, the time information is divided into time information of seconds or more and time information of less than seconds, and a first time according to the characteristics of the timepiece is added to the time information of seconds or more. Then, in the device that holds the time, for each cycle time of the clock generator, the cycle time is added to the time information of less than a second, and it is determined whether or not the time information of less than a second is carried by a second or more. Then, in the device that holds the time, the time information of the second or more to which the first time is added is set in the clock, triggered by the carry of the time information of less than a second. As a result, the device that holds the time can absorb the characteristics of the RTC in the first time, can set the time of the clock with an accuracy of less than seconds, and even a clock having no digits less than seconds can be in seconds. The time can be set with an accuracy less than (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-340672

By using the technique described in Patent Document 1, the time server after restarting can hold a substantially accurate time immediately after restarting, and can deliver the time immediately after restarting.
However, in the technique described in Patent Document 1, before turning off the power of the time server, the timing at which the time information of less than a second carries is measured, and the time information of the time of seconds or more is sent to the RTC at that timing. To set. Therefore, in the technique described in Patent Document 1, the power of the time server cannot be turned off immediately, and high-precision processing in less than a second is required before turning off the power.

The present invention has been made in view of the above problems, and is a time output device and a time output method capable of outputting reliable time information by a simple mechanism even immediately after a restart. The purpose is to provide.

In order to achieve the above object, the time output device (time server 2) according to one aspect of the present invention measures the time with the first time unit (time acquisition unit 22, oscillation circuit 23) for measuring the time, and determines the time. The second timekeeping unit (RTC25, auxiliary power supply 26) that outputs an interrupt signal at each time and continues timing even while the power is off, and the first timekeeping unit clocks when the interrupt signal is output. The time difference calculation unit (214) that calculates and holds the time difference between the time and the time measured by the second time unit as the first time difference, and when the own device is restarted and the interrupt signal is output, the said The time setting unit (RTC setting unit 212) is provided with a time setting unit (RTC setting unit 212) that sets the time corrected by adding the first time difference to the time measured by the second time unit to the first time unit, and the time setting unit is a power source. When is turned off, the time measured by the first time unit is set to the second time unit, and the second time unit updates the seconds after the time measured by the first time unit is set. when, you output an interrupt signal.

Further, in the time output device according to one aspect of the present invention, the first time unit is set to a standard time at a predetermined timing, and the time is measured with the first accuracy based on the standard time, and the second time is measured. The timekeeping unit may time the time with a second accuracy lower than the first accuracy.

Further, in the time output device according to one aspect of the present invention, the time setting unit uses the time measured by the second timekeeping unit when the power is turned off and the time when the power is turned on. 2 The time difference from the time measured by the timekeeping unit is calculated as the second time difference, and if the calculated second time difference is within the threshold (time difference threshold), the own device is restarted and the interrupt signal is output. The time corrected by adding the first time difference to the time measured by the second time unit may be set in the first time unit.

Further, in the time output device according to one aspect of the present invention, the threshold value is set to be within the error allowed by the time output device based on the time error measured by the second timekeeping unit. May be good.

In order to achieve the above object, the time output method according to one aspect of the present invention includes a first time unit that measures the time and a second time unit that measures the time and continues the time even when the power is off. A time output method of a time output device having the above, wherein the second time counting unit outputs an interrupt signal at predetermined time intervals, and the time difference calculation unit outputs the interrupt signal, the first time counting unit. The time difference calculation step of calculating and holding the time difference between the time measured by the unit and the time measured by the second time unit as the first time difference, and the time setting unit restarts its own device and the interrupt signal is output. When output, the step of setting the time corrected by adding the first time difference to the time measured by the second time unit to the first time unit and the time setting unit are turned off. When the step of setting the time measured by the first time unit to the second time portion and when the second time unit updates the seconds after the time measured by the first time unit is set. Includes a step to output an interrupt signal.

According to the present invention, reliable time information can be output even immediately after a restart.

It is a schematic block diagram of a time management system. It is a block diagram which shows the configuration example of the time server which concerns on this embodiment. It is a sequence diagram which shows the processing example at the time of restart which concerns on this embodiment. It is a flowchart which shows the processing example when the power source which concerns on this embodiment is turned off. It is a flowchart which shows the processing example when the power source which concerns on this Embodiment is turned on. It is a sequence diagram which shows the modification of the process at the time of restart which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following example, the standard time of Japan will be described as the standard time, but the standard time may be the standard time of another country, GMT (Greenwich Mean Time), or the like. In the following example, a time server will be described as an example of the time output device.

FIG. 1 is a schematic configuration diagram of the time management system 1. As shown in FIG. 1, the time management system 1 includes a time server 2 (time output device), GPS3, telephone JJY4, long wave JJY5, FM time signal 6, client 7-1, client 7-2, client 7-3, ... Consists of including.
In the following description, when one of client 7-1, client 7-2, client 7-3, ... Is not specified, it is referred to as client 7. Further, the time server 2 is connected to the client 7 via the network 8. Network 8 is, for example, a network that uses the Internet Protocol.

The time server 2 acquires the time from at least one time source of, for example, GPS3, telephone JJY4, long wave JJY5, and FM time signal 6. The time source is not limited to these, and may be, for example, an NTP (Network Time Protocol) server or the like. The time server 2 stamps the acquired time with a high-precision, high-resolution system clock, and writes it to the RTC (Real Time Clock), which is an auxiliary clock, at a predetermined timing. The time server 2 calculates and stores the time difference between the RTC and the system clock when the power is turned off. The time server 2 makes the RTC self-propelled to continue time counting while the power is off. The time server 2 acquires the RTC time the next time the power is turned on, and corrects it using the time difference in which the acquired time is stored. When the time that has been turned off is within a predetermined time and the accuracy is maintained, the time server 2 provides the corrected time to the client via the network 8 by NTP.

GPS3 is a Global Positioning System (Global Positioning System). The signal transmitted by the GPS 3 includes the position (orbit) of the satellite itself and the time when the radio wave is transmitted. The accuracy of the time is ± 1 [ms].
The telephone JJY4 is a time supply system using a telephone line. The accuracy of the time is ± 10 [ms].

The long wave JJY5 is a time signal included in the radio wave of the long wave JJY broadcast in the frequency band of 30 to 300 kHz, that is, the radio wave of the so-called radio clock. The accuracy of the time is ± 100 [ms].
FM time signal 6 is a time signal of the Japan Broadcasting Corporation (NHK) broadcast in the FM frequency band. The NHK time signal is configured to transmit a 440 Hz forecast sound that lasts for 0.1 seconds three times at 1-second intervals, and then transmits an 880 Hz positive sound that continues for 1 second and attenuates 1 second later. There is. The accuracy of the time is ± 100 [ms].

The client 7 is, for example, a server or a personal computer. The client 7 acquires the time provided by the time server 2 and adjusts the current time.

Next, a configuration example of the time server 2 will be described.
FIG. 2 is a block diagram showing a configuration example of the time server 2 according to the present embodiment. As shown in FIG. 2, the time server 2 includes a control unit 21, a time acquisition unit 22 (first timekeeping unit), an oscillation circuit 23 (first timekeeping unit), an RTC25 (second timekeeping unit), and an auxiliary power supply 26 (second timekeeping unit). 2 timekeeping unit), a storage unit 27, and a communication unit 28. The control unit 21 includes a time measuring unit 211, an RTC setting unit 212 (time setting unit), a detection unit 213, and a time difference calculation unit 214.

The control unit 21 clocks the system clock at the first frequency generated by the oscillation circuit 23 in accordance with the time acquired by the time acquisition unit 22. The control unit 21 controls the communication unit 28 to provide the time of the system clock to the client 7. The control unit 21 stores the time difference between the system clock and the RTC 25 in the storage unit 27 when the power of the time server 2 is turned off. When restarting, the control unit 21 corrects the time of the RTC 25 by using the time difference stored in the storage unit 27. The control unit 21 controls the communication unit 28 to provide the corrected time to the client 7. After restarting, the control unit 21 adjusts the system clock to the time acquired by the time acquisition unit 22 when the time acquisition unit 22 can acquire the time information.

The timekeeping unit 211 clocks the system clock using the first frequency output by the control unit 21. The timekeeping unit 211 adjusts the system clock using the time information output by the time acquisition unit 22. After restarting, the timekeeping unit 211 adjusts the system clock to the time output from the RTC setting unit 212. The timekeeping unit 211 uses the system clock thus adjusted until the time acquisition unit 22 outputs the time information. The accuracy of the system clock time is, for example, 0.1 ppm.

The RTC setting unit 212 adjusts the time of the RTC 25 to the time of the system clock at a predetermined timing. The RTC setting unit 212 adjusts the time of the RTC 25 to the time of the system clock, for example, when the detection unit 213 outputs the ON information. The RTC setting unit 212 acquires the time (off time) of the RTC 25 and stores it in the storage unit 27 when the detection unit 213 outputs the off information or when the RTC 25 activates the interrupt handler thereafter. The RTC setting unit 212 acquires the time (on time) of the RTC 25 and stores it in the storage unit 27 when the detection unit 213 outputs the ON information or when the RTC 25 activates the interrupt handler thereafter.

The detection unit 213 detects that the time server 2 has been turned off and turned on due to some factor such as maintenance. The detection unit 213 outputs off information indicating that the time server 2 has been turned off to the RTC setting unit 212. The detection unit 213 outputs on information indicating that the time server 2 has been turned on to the RTC setting unit 212.

When the RTC 25 activates the interrupt handler, the time difference calculation unit 214 calculates the time difference between the RTC 25 time (off time) and the system clock as the first time difference, and stores the calculated first time difference in the storage unit 27. The RTC setting unit 212 (time setting unit) acquires the time (on time) of the RTC25 when the RTC25 activates the interrupt handler after restarting, and the second time difference between the acquired time (on time) and the off time. Is calculated. The RTC setting unit 212 determines whether or not the calculated second time difference is within the time difference threshold value stored by the storage unit 27. When the second time difference is within the time difference threshold value, the RTC setting unit 212 corrects the on time using the first time difference, and outputs the corrected time information to the time measuring unit 211. When the second time difference is larger than the time difference threshold value, the RTC setting unit 212 does not output the time to the time measuring unit 211. Here, the time difference threshold is the time based on the error of RTC25, for example, several hours. For example, if the error of RTC25 is ± 5 ppm and ± 400 [ms] per day, if the error allowed by the time server 2 is about ± 100 [ms], 100/400, that is, 6 hours (=). 24 hours / 4) is the time difference threshold. That is, in the present embodiment, when the relationship of ((on time)-(off time)) <time difference threshold can be maintained for the time (when the interrupt handler is activated) issued by RTC25, the time shifted at the time of off is added. By doing so, the time after restarting is corrected.

The time acquisition unit 22 acquires the time from at least one time source of, for example, GPS3, telephone JJY4, long wave JJY5, and FM time signal 6, and outputs the acquired time information to the control unit 21.
The oscillation circuit 23 includes, for example, a crystal oscillator. The oscillation circuit 23 generates a signal of the first frequency by combining with the oscillator, and outputs the generated signal of the first frequency to the control unit 21. The first frequency is, for example, 500 [MHz] to 1 [GHz]. The oscillator may be TCXO (temperature-compensated crystal oscillator), OCXO (crystal oscillator with a constant temperature bath), or the like.

The time of the RTC 25 is set at a predetermined timing by the RTC setting unit 212. The time that can be written to the RTC 25 and the time that can be read are, for example, in seconds. After setting the time, the RTC25 measures the time by itself. The RTC 25 activates an interrupt handler when the time is updated at predetermined time intervals (for example, every second). The RTC 25 measures the time using the power from the auxiliary power supply 26 even while the power of the time server 2 is off. The accuracy of RTC25 at room temperature is, for example, ± 5 ppm, which is ± 400 [ms] per day.
The auxiliary power supply 26 is, for example, a supercapacitor such as a secondary battery or an electric double layer capacitor.

The storage unit 27 stores the program required for controlling the time server 2, the time difference threshold value, the first time difference between the RTC 25 and the system clock, and the off time.
The communication unit 28 provides the time information to the client 7 via the network 8 according to the control of the control unit 21.

Next, an example of the time setting procedure will be described with reference to FIGS. 3 to 5.
FIG. 3 is a sequence diagram showing an example of processing at the time of restart according to the present embodiment. FIG. 4 is a flowchart showing a processing example when the power supply according to the present embodiment is turned off. FIG. 5 is a flowchart showing a processing example when the power supply according to the present embodiment is turned on.
In FIG. 3, the horizontal axis represents time. Here, it is assumed that the accuracy of the RTC25 is ± 5 ppm, the error allowed for the time server is ± 100 [ms], and as a result, the time difference threshold is 6 hours.

First, an example of the procedure when the power is turned off will be described with reference to FIGS. 3 and 4.
(Step S1) When the detection unit 213 outputs the off information, the RTC setting unit 212 acquires the time of the system clock clocked by the clock unit 211, and stores the time obtained by rounding down the seconds or less of the acquired time in the storage unit 27. Remember. In the example of FIG. 3, the acquired time is 1: 23: 45.89 (1:23:45.89 seconds), and the memory stored in the storage unit 27 is 1:23:45 (1:23:45). Seconds).

(Step S2) The RTC setting unit 212 adjusts the time of the RTC 25 to the acquired time. As a result, in the example shown in FIG. 3, the RTC setting unit 212 sets (sets) the time of the RTC 25 to 1:23:45 (1:23:45).

(Step S3) The RTC25 activates an interrupt handler when the seconds are updated. In the example shown in FIG. 3, the interrupt handler is activated at 1:23: 46.00 (1:23:46.00).

(Step S4) The time difference calculation unit 214 acquires the time of the system clock when the interrupt handler is activated from the RTC 25 and the time of the RTC 25, and stores the acquired time in the storage unit 27 as an off time. In the example shown in FIG. 3, the system clock time is 1: 23: 46.67 (1:23:46.67) and the RTC25 time is 1:23:46 (1:23:46). is there.

(Step S5) The time difference calculation unit 214 calculates the time difference between the time of the RTC 25 and the system clock as the first time difference, and stores the calculated first time difference in the storage unit 27. In the example shown in FIG. 3, the time of RTC25 is 1: 23: 46.00 and the time of the system clock is 1: 23: 46.67, so that the first time difference is 0.67.

Next, an example of the procedure when the power is turned on will be described with reference to FIGS. 3 and 5. In the example shown in FIG. 3, the shutdown period (the period in which the power is off) is 1 minute and 1 second.

(Step S11) The RTC 25 continues timing with the power of the auxiliary power source 26 during the shutdown period. Subsequently, the RTC 25 activates the interrupt handler when the second is updated. In the example shown in FIG. 3, the RTC25 activates the interrupt handler at 1:24:47.00 (1:24:47.00).

(Step S12) The RTC setting unit 212 acquires the time of the RTC 25 when the RTC 25 activates the interrupt handler, and stores the acquired time in the storage unit 27 as an on time. In the example shown in FIG. 3, the time of RTC25 is 1:23:47 (1:23:47).

(Step S13) The RTC setting unit 212 calculates the second time difference between the on time and the off time, and determines whether or not the calculated second time difference is within the time difference threshold value. When the RTC setting unit 212 determines that the second time difference is within the time difference threshold value, the RTC setting unit 212 adds the first time difference to the on time to correct it. In the example shown in FIG. 3, the second time difference between the off time and the on time is 1 minute and 1 second (= 1: 24: 47-1: 23: 46), which is equal to or less than the time difference threshold (6 hours). The time is corrected to 1: 24: 47.67 (1:24:47.67) by adding the first time difference of 0.67 to the on time of 1: 24: 47.00.

(Step S14) The RTC setting unit 212 sets the system clock at the corrected time. In the example shown in FIG. 3, the RTC setting unit 212 sets the system clock to 1: 24: 47.67 (1:24:47.67 seconds).

As described above, in the present embodiment, the time difference between the RTC25 and the system clock is acquired immediately before shutdown, and the time difference is added to the time of the RTC25 running on its own after restarting to operate as the system clock. Here, since the first time difference is immediately before shutdown, the accuracy of the time when the RTC25 is corrected by this time difference after restarting is the accuracy of the time immediately before shutdown. That is, according to the embodiment, the accuracy of the system clock set after the restart can be the same as the accuracy immediately before the shutdown.
As a result, the service can be continued to be provided by using the system clock corrected in this way until the time information can be acquired. If the time server 2 can only acquire the time signal from GPS 3, it takes up to 12.5 minutes to receive all the data and use the time information. If the time server 2 can only acquire the time signal from the FM time signal 6, it takes a maximum of 59 minutes and 59 seconds after the restart to acquire the next time signal because the time signal is once an hour. Even in such a case, according to the present embodiment, if the shutdown time is within the permissible range based on the error in RTC25, the service provision is resumed immediately even after the restart. Can be done. Further, immediately before shutdown, it is not necessary to write the time to the RTC 25 at a highly accurate timing as in the prior art, and the workload of the time server 2 can be reduced.

<Modification example>
Here, a modified example of the process shown in FIG. 3 will be described.
In the example described with reference to FIG. 3, the control unit 21 writes the system clock time to the RTC25 before shutdown, and then acquires the time difference when the RTC25 updates the seconds, but this is limited to this. Absent. Since the RTC 25 activates the interrupt handler every second, the time difference between the system clock and the RTC 25 may be stored every second.
FIG. 6 is a sequence diagram showing a modified example of the process at the time of restart according to the present embodiment. In the example shown in FIG. 6, the time of the system clock is written to the RTC 25 before step S21.

(Step S21) The RTC setting unit 212 activates the interrupt handler every second.
(Step S22) The time difference calculation unit 214 acquires the time of the system clock when the RTC 25 activates the interrupt handler and the time of the RTC 25, and stores the acquired time in the storage unit 27 as an off time.

(Step S23) The RTC setting unit 212 outputs an interrupt handler to the time difference calculation unit 214 every second.
(Step S24) The time difference calculation unit 214 acquires the time of the system clock when the RTC 25 activates the interrupt handler and the time of the RTC 25, overwrites the acquired off time with the storage unit 27, and updates the time. In the example shown in FIG. 6, the first time difference calculated in step S24 is the time difference between the system clock immediately before shutdown and the RTC25. The time difference calculation unit 214 compares the time difference calculated one second ago (step S22) with the current time difference (step S24), and if there is no change, the time difference calculated in the storage unit 27 is used for the first time difference. You may not write it.

(Steps S25 to S28) The RTC25 and the RTC setting unit 212 perform the processes of steps S25 to S28 in the same manner as the processes of steps S11 to S14.

As described above, according to the modification shown in FIG. 6, the time difference between the system clock and the RTC 25 is calculated every second and stored in the storage unit 27. As a result, according to the modified example, since the time difference is updated every second, the time difference immediately before shutdown can be held in the storage unit 27, and the time acquired from the RTC 25 is corrected using this held time difference. And can continue to provide services. The accuracy of the time set in the system clock after restart is the accuracy of the time obtained by correcting the time of RTC25 acquired immediately before shutdown by the time difference between the system clock and RTC25, so it is the accuracy of the time of the system clock before shutdown. Equivalent. That is, even in the modified example, the accuracy of the system clock set after the restart is the same as the accuracy immediately before the shutdown.
Therefore, according to the modified example, even if the time of RTC25 is deviated by one year or more, the time difference is updated every second, so that no special processing is required in consideration of immediately before shutdown, and the retained time difference can be determined. It can be used to correct the time acquired from the RTC 25 and continue to provide the service.

In the above-mentioned example, the time server 2 has been described as an example of the time output device, but the present invention is not limited to this. The time output device having the configuration shown in FIG. 2 can also be applied to a personal computer, a server, a tablet terminal, a portable electronic device, or the like.

A program for realizing all or a part of the functions of the control unit 21 in the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. As a result, the processing performed by the control unit 21 may be performed. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Further, the "computer system" shall also include a WWW system provided with a homepage providing environment (or display environment). Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Furthermore, a "computer-readable recording medium" is a volatile memory (RAM) inside a computer system that serves as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, it shall include those that hold the program for a certain period of time.

Further, the program may be transmitted from a computer system in which this program is stored in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. Further, the above program may be for realizing a part of the above-mentioned functions. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned function in combination with a program already recorded in the computer system.

1 ... Time management system, 2 ... Time server, 3 ... GPS, 4 ... Telephone JJY, 5 ... Long wave JJY, 6 ... FM time signal, 7,7-1,7-2,7-3 ... Client, 21 ... Control unit , 22 ... Time acquisition unit, 23 ... Oscillation circuit, 25 ... RTC, 26 ... Auxiliary power supply, 27 ... Storage unit, 28 ... Communication unit, 211 ... Time signal unit, 212 ... RTC setting unit, 213 ... Detection unit, 214 ... Time difference Calculation unit

Claims (5)

The first timekeeping part that measures the time and
The second clock section that clocks the time, outputs an interrupt signal at predetermined time intervals, and continues timing even when the power is off.
When the interrupt signal is output, the time difference calculation unit calculates and holds the time difference between the time measured by the first timekeeping unit and the time measured by the second timekeeping unit as the first time difference.
When the own device is restarted and the interrupt signal is output, the time setting unit that sets the time corrected by adding the first time difference to the time measured by the second time unit in the first time unit. ,
Equipped with a,
When the power is turned off, the time setting unit sets the time measured by the first time unit to the second time unit.
Said second time counting unit, when the first clock unit updates the seconds after being set time of clocking, the time output device you output an interrupt signal. The first time unit is set to a standard time at a predetermined timing, and the time is measured with the first accuracy based on the standard time.
The time output device according to claim 1, wherein the second time unit measures the time with a second accuracy lower than the first accuracy. The time setting unit
The time difference between the time measured by the second time section when the power is turned off and the time measured by the second time section when the power is turned on is calculated and calculated as the second time difference. When the second time difference is within the threshold value, when the own device is restarted and the interrupt signal is output, the time corrected by adding the first time difference to the time measured by the second time unit is the time corrected. 1 The time output device according to claim 1 or 2, which is set in the time section. The time output device according to claim 3 , wherein the threshold value is a time within an error allowed by the time output device based on an error in the time measured by the second time unit. It is a time output method of a time output device having a first time unit that measures the time and a second time unit that measures the time and continues the time measurement even when the power is off.
The step that the second timekeeping part outputs an interrupt signal at predetermined time intervals,
When the interrupt signal is output, the time difference calculation unit calculates and holds the time difference between the time measured by the first time unit and the time measured by the second time unit as the first time difference. When,
When the own device is restarted and the interrupt signal is output, the time setting unit sets the time corrected by adding the first time difference to the time measured by the second time unit in the first time unit. Steps to do and
When the time setting unit turns off the power, the step of setting the time measured by the first timekeeping unit to the second timekeeping unit, and
A step of outputting an interrupt signal when the second clock unit updates the seconds after the time measured by the first clock unit is set.
Time output method including.

Images