KR102388889B1 - Time synchronizing device, time synchronizing method, and time synchronizing program stored in recording medium - Google Patents

Abstract

In the time synchronization device 10 , the time acquisition unit 21 acquires an external time that is the time of the external clock 51 from the time transmission device 50 . The internal clock setting unit 22 transmits the external time acquired by the time acquisition unit 21 to the time conversion device 40 . The time conversion unit 26 converts the external time into a unique time that is a time within the management range of the internal clock 14 . The internal clock setting unit 22 sets the unique time converted by the time converting unit 26 to the internal clock 14 .

Description

Time synchronizing device, time synchronizing method, and time synchronizing program stored in recording medium

The present invention relates to a technique for synchronizing an internal clock with an external time acquired from an external clock.

There is a technique for synchronizing the internal clock with the external clock by updating the internal clock with the external time acquired from the external clock.

Patent Document 1 describes correcting the time based on a comparison result between the external time acquired from the external clock and the time of the internal clock. In Patent Document 1, thereby, an attempt is made to improve the reliability of the internal clock.

[Patent Document 1] Japanese Patent Laid-Open No. 10-178666

In some cases, there is a limit to the management range, which is the range of time that the device can manage. As a specific example, in the 32-bit version of Linux (registered trademark), when the year 2038 is reached, the time management variable overflows and falls outside the management range. In this 32-bit version of Linux (registered trademark), the problem that time management variables overflow when 2038 is reached is called the 2038 problem.

If the management range is limited and the internal clock is simply updated by the external time, the internal clock may not be correctly updated. If the internal clock is not updated correctly, the device cannot continue to operate correctly.

An object of the present invention is to appropriately synchronize time even when there is a limit to the management range.

A time synchronization device according to the present invention,

a time acquisition unit for acquiring an external time that is the time of an external clock;

Internal clock setting for transmitting the external time acquired by the time acquisition unit to a time conversion device, converting the external time into a unique time that is a time within a management range of the internal clock, and setting the unique time to the internal clock wealth

to provide

In the present invention, after converting the external time into a unique time that is a time within the management range of the internal clock, it is set in the internal clock. Thereby, the time outside the management range is not set in the internal clock, and the time can be appropriately synchronized.

1 is a hardware configuration diagram of a time synchronization device 10 according to a first embodiment.
Fig. 2 is a functional configuration diagram of a time synchronization device 10 according to the first embodiment.
Fig. 3 is a functional configuration diagram of a modified example of the time synchronization device 10 according to the first embodiment.
Fig. 4 is a flowchart of a process in which the time synchronization device 10 according to the first embodiment synchronizes the time of the internal clock 14 with the time of the external clock 51;
Fig. 5 is a flowchart of time conversion processing according to the first embodiment;
Fig. 6 is a flowchart of a process in which the time synchronization device 10 according to the first embodiment uses the time of the internal clock 14;
Fig. 7 is a flowchart of inverse time transformation processing according to the first embodiment;
Fig. 8 is an explanatory view of the effect of the time synchronization device 10 according to the first embodiment;
Fig. 9 is a flowchart of time conversion processing according to the second embodiment;
Fig. 10 is an explanatory diagram of a process in which the time synchronizer 10 according to the second embodiment synchronizes the time of the internal clock 14 with the external NTP time of an NTP server;
Fig. 11 is an explanatory diagram of a method for setting a conversion time according to the second embodiment;
12 is an explanatory diagram of NTP (Network Time Protocol) time and UN time.
Fig. 13 is a flowchart of inverse time transformation processing according to the second embodiment;
Fig. 14 is an explanatory view of the effect of the time synchronization device 10 according to the second embodiment;
Fig. 15 is a flowchart of a process in which the time synchronizer 10 according to the third embodiment synchronizes the time of the internal clock 14 with the external PTP time of a PTP (Precision Time Protocol) master.
Fig. 16 is an explanatory diagram of a process in which the time synchronizer 10 according to the third embodiment synchronizes the time of the internal clock 14 with the external PTP time of the PTP master;
Fig. 17 is a flowchart of time conversion processing according to the third embodiment;
18 is an explanatory diagram of NTP time, UN time, and PTP time.

(Embodiment 1)

***Description of configuration***

With reference to FIG. 1, the hardware structure of the time synchronization apparatus 10 which concerns on Embodiment 1 is demonstrated.

The time synchronization device 10 is a device that acquires time information from the time transmission device 50 and performs time synchronization. The time synchronization device 10 includes a clock generator 11 , a processor 12 , a NIC 13 (Network Interface Card), an internal clock 14 , a main memory 15 , and a peripheral device 16 . ) of the hardware. The processor 12 is connected to other hardware via a signal line 17 .

The clock generator 11 is an element or device that supplies an operating clock to the processor 12 . The processor 12 is an element or device that performs software processing such as time synchronization. The NIC 13 is an element or device that transmits/receives packets to and from an external device called the time transmission device 50 . The internal clock 14 is an element or device for maintaining the internal time in the time synchronization device 10 . The main memory 15 is an element or device for holding instructions and data necessary for software processing. The peripheral device 16 is an element or device that performs input/output of the time synchronization device 10 .

The time transmitting device 50 is a device that includes an external clock 51 and transmits an external time that is the time of the external clock 51 in response to a request from a device connected via the transmission path 61 . The external clock 51 is an element or device that always keeps accurate time.

With reference to FIG. 2, the functional structure of the time synchronization apparatus 10 which concerns on Embodiment 1 is demonstrated.

The time synchronizer 10 includes, as functional components, a time acquisition unit 21 , an internal clock setting unit 22 , a time management unit 23 , an internal clock reference unit 24 , and a time use unit ( 25 ), a time conversion unit 26 , and an inverse time conversion unit 27 . The internal clock setting unit 22 includes a post-conversion acquisition unit 221 . In addition, the internal clock reference unit 24 includes an inverse-transformed acquisition unit 241 .

The function of each functional component is realized by software. Specifically, a program for realizing the function of each functional component is read into the main memory 15 by the processor 12 and executed by the processor 12 . Thereby, the function of each functional component is realized. Moreover, the program which implement|achieves the function of each functional element is memorize|stored in the storage medium called HDD (Hard Disk Drive), and is read through the peripheral device 16. As shown in FIG.

The time conversion unit 26 and the time inverse conversion unit 27 are functional components of the time conversion device 40 . In FIG. 2 , the time synchronization device 10 is configured to include the time conversion device 40 . However, as shown in FIG. 3 , the time conversion device 40 may be configured as a different device from the time synchronization device 10 . In this case, the time synchronization device 10 and the time conversion device 40 are connected via a transmission path 62 .

The time acquisition unit 21 is a function of acquiring the external time of the external clock 51 from the time transmission device 50 . The internal clock setting unit 22 is a function of setting the unique time obtained by converting the external time acquired by the time acquiring unit 21 by the time converting unit 26 to the internal clock 14 . The post-conversion acquisition unit 221 is a function of transmitting the time between the internal clock setting unit 22 and the time conversion unit 26 . The time management unit 23 is a function of managing the internal clock 14 .

The internal clock reference unit 24 is a function of obtaining a reference time obtained by referring to the internal clock 14 and converting the internal time, which is the time indicated by the internal clock, by the time inverse transformation unit 27 . The post-inverse transformation acquisition unit 241 is a function of transferring time between the internal clock reference unit 24 and the time inverse transformation unit 27 . The time use unit 25 is a function of using the reference time acquired by the internal clock reference unit 24 .

The time conversion unit 26 is a function of performing conversion by shifting the time by the conversion time. The time inverse transformation unit 27 is a function of performing inverse transformation by shifting the time by the transformation time in the opposite direction to the time transformation unit 26 .

***Description of action***

The operation of the time synchronization device 10 according to the first embodiment will be described with reference to FIGS. 4 to 7 .

The operation procedure of the time synchronization device 10 according to the first embodiment corresponds to the time synchronization method according to the first embodiment. In addition, the program which implements the operation|movement of the time synchronization apparatus 10 concerning Embodiment 1 corresponds to the time synchronization program concerning Embodiment 1. As shown in FIG.

With reference to FIG. 4 , the processing in which the time synchronization device 10 according to the first embodiment synchronizes the time of the internal clock 14 with the time of the external clock 51 will be described.

(Step S11: Time acquisition processing)

The time acquisition unit 21 acquires the external time of the external clock 51 from the time transmission device 50 via the NIC 13 . The time acquisition unit 21 writes the acquired external time into the main memory 15 .

(Step S12: Time conversion processing)

The internal clock setting unit 22 transmits the external time acquired in step S11 to the time converting unit 26 via the post-conversion acquisition unit 221 , and transmits the external time to a time within the management range of the internal clock 14 . converted to a unique time of day.

(Step S13: Internal clock setting processing)

The internal clock setting unit 22 transmits the unique time converted in step S12 to the time management unit 23 to set the unique time in the internal clock 14 .

After a certain period of time has elapsed, the process returns to step S11 again. Thereby, the time of the internal clock 14 is synchronized with the time of the external clock 51 again after a certain period of time has elapsed.

With reference to FIG. 5, the time conversion process (step S12 of FIG. 4) according to Embodiment 1 is demonstrated.

(Step S21: Time transmission processing)

The internal clock setting unit 22 reads the external time acquired in step S11 from the main memory 15 . The internal clock setting unit 22 transmits the external time to the time converting unit 26 via the post-conversion acquisition unit 221 . The time conversion unit 26 acquires the transmitted external time.

(Step S22: Conversion processing)

The time conversion unit 26 converts the external time into an intrinsic time by adding the conversion time to the external time acquired in step S21. The conversion time is positive time when the time advances to the future, and negative time when the time returns to the past.

(Step S23: Time return processing)

The time conversion unit 26 transmits the unique time converted in step S22 to the post-conversion acquisition unit 221 . The internal clock setting unit 22 acquires the transmitted unique time through the post-conversion acquisition unit 221 .

Referring to FIG. 6 , processing in which the time synchronization device 10 according to the first embodiment uses the time of the internal clock 14 will be described.

(Step S31: Time reading processing)

The internal clock reference unit 24 reads the internal time that is the time indicated by the internal clock 14 in response to a request from the time management unit 23 . The internal clock reference unit 24 writes the read internal time into the main memory 15 .

(Step S32: Time inverse transformation processing)

The internal clock reference unit 24 transmits the internal time read in step S31 to the time inverse transformation unit 27 via the inverse-transformed acquiring unit 241, and is a reverse process of the processing in which the external time is converted into the intrinsic time. By performing , the internal time is converted into a reference time.

(Step S33: time use processing)

The time use unit 25 performs processing using the reference time converted in step S32 and obtained. Thereby, the time use unit 25 performs processing using the reference time obtained by converting the internal time, not the internal time indicated by the internal clock 14 .

With reference to FIG. 7, the time inverse transform process (step S32 of FIG. 6) according to Embodiment 1 is demonstrated.

(Step S41: Time transmission processing)

The internal clock reference unit 24 reads the internal time read in step S31 from the main memory 15 . The internal clock reference unit 24 transmits the internal time to the time inverse transformation unit 27 via the acquisition unit 241 after the inverse transformation. The time inverse transform unit 27 acquires the transmitted internal time.

(Step S42: Inverse transform processing)

The time inverse transform unit 27 converts the internal time into a reference time by subtracting the conversion time from the internal time acquired in step S41.

(Step S43: Time return processing)

The time inverse transform unit 27 transmits the reference time obtained by transforming in step S42 to the post-inverse transform acquisition unit 241 . The internal clock reference unit 24 acquires the transmitted reference time through the acquisition unit 241 after the inverse transformation.

***Effect of Embodiment 1 ***

As described above, the time synchronization device 10 according to the first embodiment converts the external time into a unique time that is a time within the management range of the internal clock, and then sets it in the internal clock 14 . Thereby, the time outside the management range is not set in the internal clock, and the time can be appropriately synchronized.

In addition, the time synchronization device 10 according to the first embodiment converts the internal time, which is the time indicated by the internal clock 14, into the reference time by performing the reverse process of the process of converting the external time into a unique time. Use after conversion. Thereby, processing may be performed using the time synchronized with the external time.

With reference to FIG. 8, the effect of the time synchronization apparatus 10 which concerns on Embodiment 1 is demonstrated.

In FIG. 8 , the relationship between the external time of the external clock 51 and the internal time of the internal clock 14 in the case where the time synchronization device 10 performs time synchronization with the external clock 51 is shown. In Fig. 8, the conversion is performed so that the internal time becomes past by the conversion time from the external time. Then, the internal clock 14 operates while synchronizing with the external clock 51 and maintaining an interval between the external time of the external clock 51 and a predetermined time (conversion time).

Thereby, even when there is a restriction on the time manageable by the time synchronizing device 10, the time can be set in a range manageable by the time synchronizing device 10, and the apparatus can continue the correct operation.

***OTHER CONFIGURATIONS***

<Modification 1>

In the first embodiment, each functional component is realized by software. However, as Modification Example 1, each functional component may be realized by hardware. About this modification 1, the point different from Embodiment 1 is demonstrated.

When each functional component is realized by hardware, the time synchronization device 10 includes an electronic circuit instead of the processor 12 and the main memory 15 . The electronic circuit is a dedicated circuit for realizing each functional component and the function of the main memory 15 .

As the electronic circuit, single circuit, complex circuit, programmed processor, parallel programmed processor, logic IC, GA (Gate Array), ASIC (Application Specific Integrated Circuit), and FPGA (Field-Programmable Gate Array) are assumed.

Each functional component may be realized by one electronic circuit, or each functional component may be realized by dispersing it in a plurality of electronic circuits.

<Modification 2>

As the second modification, some of each functional component may be realized by hardware, and each other functional component may be realized by software.

(Embodiment 2)

In the second embodiment, a specific example of the operation of the time synchronization device 10 described in the first embodiment will be described. In the second embodiment, the 2038 year problem is used as an example of a case where the management range that is the range of the time that the time synchronization device 10 can manage is limited.

The 2038 problem is a problem in which the time management variable overflows when the year 2038 is reached in Linux (registered trademark) of the 32-bit version. Linux (registered trademark) manages the time by having UNIX (registered trademark) time in the system internal clock. Hereinafter, the UNIX (registered trademark) time is referred to as the UN time. The UN time is the time expressed in the number of seconds elapsed from the base year with 0 am on January 1, 1970 as the base year. Since the system internal clock is defined as a signed integer type, in the case of a 32-bit version of Linux (registered trademark), the time management variable overflows after 3:14:07 on January 19, 2038.

***Description of configuration***

The hardware configuration of the time synchronization device 10 is the same as the hardware configuration of the time synchronization device 10 according to the first embodiment shown in FIG. 1 .

Here, the processor 12 is a 32-bit processor. In addition, the time transmitting device 50 is a device that transmits time information that can be received by a Linux (registered trademark) system such as an NTP (Network Time Protocol) server or a GPS (Global Positioning System) satellite. In the second embodiment, the time transmission device 50 is described as an NTP server.

The functional configuration of the time synchronization device 10 is the same as that of the time synchronization device 10 according to the first embodiment shown in FIG. 2 .

Here, the time acquisition unit 21, the internal clock setting unit 22, and the time conversion unit 26 are realized by an NTP client. The time management unit 23 is realized by a Linux (registered trademark) kernel. The internal clock setting unit 22 converts the NTP time, which is the external time obtained from the NTP server, into a unique time, then calculates the UN time, and sets it in the internal clock 14 .

***Description of action***

The operation of the time synchronization device 10 according to the second embodiment will be described with reference to FIGS. 9 to 13 .

The operation procedure of the time synchronization device 10 according to the second embodiment corresponds to the time synchronization method according to the second embodiment. In addition, the program for realizing the operation|movement of the time synchronization apparatus 10 concerning Embodiment 2 corresponds to the time synchronization program concerning Embodiment 2. FIG.

In the following description in Embodiment 2, the external time acquired from the NTP server is called an external NTP time. The native time converted from the external NTP time is called the native NTP time. The UN time converted from the external NTP time is called the external UN time. The UN time converted from the native NTP time is called the native UN time.

Time conversion processing (step S12 in FIG. 4 ) according to the second embodiment will be described with reference to FIGS. 9 and 10 .

(Step S51: Time transmission processing)

The internal clock setting unit 22 reads the external NTP time, which is the external time acquired in step S11 , from the main memory 15 . The internal clock setting unit 22 transmits the external NTP time to the time converting unit 26 via the post-conversion acquisition unit 221 . The time conversion unit 26 acquires the transmitted external NTP time.

(Step S52: Unique conversion processing)

The time conversion unit 26 converts the external NTP time into the intrinsic NTP time by adding the conversion time to the external NTP time acquired in step S51. Specifically, the time conversion unit 26 converts the external NTP time into a unique NTP time that is a time within the management range of the internal clock 14 by adding the conversion time.

At this time, the time conversion unit 26 sets the conversion time so that the intrinsic NTP time becomes the earliest possible time within the management range. Thereby, without changing the conversion time, it becomes possible to lengthen the period during which the time can be managed within the management range. Here, the time conversion unit 26 sets the conversion time so that the intrinsic NTP time becomes the time as close as possible to 0 am on January 1, 1970, which is the base year of the UN time.

In addition, at this time, the time conversion unit 26 sets the conversion time so that the number of periodic fluctuations that are periodic fluctuations of the time that is not caused by the external time system becomes the same. Here, the periodic variation is a leap year. Leap years, as a rule, come back once every four years. Therefore, as shown in FIG. 11, the time conversion part 26 sets the number of multiples of 4 of 4 years and 40 years as conversion time. For example, if the conversion time is -40 years, the conversion time is -40 years (UTC) = -(60 seconds × 60 minutes × 24 hours × (365 days × 30 years + 366 days × 10 years)) = - 1,262,304,000 seconds. This eliminates the need to recalculate the conversion time each time. On the other hand, if the conversion time is set to two years, a case in which a leap year is included or a case in which a leap year is not included occurs, and the conversion time must be recalculated according to the external NTP time.

Also, a year that is divisible by 100 is not a leap year, and a year that is divisible by 400 is not a leap year. Then, the time conversion unit 26 may set the conversion time in consideration of this rule as necessary.

(Step S53: UN conversion processing)

The time conversion unit 26 converts the unique NTP time converted and obtained in step S52 into a unique UN time.

As shown in Fig. 12, the NTP time and the UN time have different base years. However, both the NTP time and the UN time use UTC (Coordinated Universal Time), which takes leap seconds into account, as a time system. Therefore, when converting the NTP time to the UN time, the fixed time due to the difference in the base year may be added.

(Step S54: Time return processing)

The time conversion unit 26 transmits the unique UN time converted in step S53 to the post-conversion acquisition unit 221 . The internal clock setting unit 22 acquires the transmitted unique UN time via the post-conversion acquisition unit 221 .

Thereby, in step S13 of FIG. 4 , the unique UN time is set in the internal clock 14 .

With reference to FIG. 13, the time inverse transformation process (step S32 of FIG. 6) according to Embodiment 2 is demonstrated.

(Step S61: Time transmission processing)

The internal clock reference unit 24 reads the internal UN time, which is the time indicated by the internal clock 14 obtained in step S31, from the main memory 15 . The internal clock reference unit 24 transmits the internal UN time to the time inverse transformation unit 27 via the acquisition unit 241 after the inverse transformation. The time inverse transform unit 27 acquires the transmitted internal UN time.

(Step S62: Inverse transform processing)

The time inverse transform unit 27 converts the internal UN time into the reference UN time by subtracting the conversion time from the internal UN time obtained in step S61. For example, when the conversion time is 40 years, the time inverse conversion unit 27 subtracts -1,262,304,000 seconds from the internal UN time.

(Step S63: Time return processing)

The time inverse transform unit 27 transmits the reference UN time obtained by transforming in step S62 to the post-inverse transform acquisition unit 241 . The internal clock reference unit 24 acquires the transmitted reference UN time through the acquisition unit 241 after the inverse transformation.

Thereby, in step S33 of Fig. 6, the reference UN time in which the internal UN time is shifted by the conversion time is used.

In addition, here, the time use part 25 demonstrated as what uses the UN time. However, when the time use unit 25 uses the NTP time, it is necessary to further subtract the fixed time due to the difference between the NTP time and the base year of the UN time from the reference UN time.

***Effect of Embodiment 2 ***

As described above, the time synchronization device 10 according to the second embodiment converts the external NTP time into a unique NTP time, and then converts it into a unique UN time. As a result, as shown in Fig. 14, in the 32-bit version of Linux (registered trademark), even when the external time exceeds 2038 and enters the unmanageable time range, the time of the internal clock 14 is maintained within the management range. It is possible to operate as a view within.

Moreover, as shown in FIG. 10, when conversion by conversion time is not performed, the external NTP time is converted to the external UN time. Therefore, when the external time exceeds 2038 and enters the unmanageable time range, the time of the internal clock 14 becomes unmanageable time.

(Embodiment 3)

The third embodiment differs from the second embodiment in that a PTP (Precision Time Protocol) master is used as the time transmission device 50 instead of the NTP server. In Embodiment 3, these differences are demonstrated, and description is abbreviate|omitted about the same point.

***Description of configuration***

The hardware configuration of the time synchronization device 10 is the same as the hardware configuration of the time synchronization device 10 according to the first embodiment shown in FIG. 1 . Here, the time transmission device 50 is a PTP master.

The functional configuration of the time synchronization device 10 is the same as that of the time synchronization device 10 according to the first embodiment shown in FIG. 2 .

Here, the time acquisition unit 21, the internal clock setting unit 22, and the time conversion unit 26 are realized by a PTP slave. The time management unit 23 is realized by a Linux (registered trademark) kernel. The internal clock setting unit 22 converts the PTP time, which is the external time acquired from the PTP master, into a unique time, then calculates the UN time and sets it in the internal clock 14 .

***Description of action***

An operation of the time synchronization device 10 according to the third embodiment will be described with reference to FIGS. 15 to 17 .

The operation procedure of the time synchronization device 10 according to the third embodiment corresponds to the time synchronization method according to the third embodiment. Moreover, the program which implement|achieves the operation|movement of the time synchronization device 10 concerning Embodiment 3 corresponds to the time synchronization program concerning Embodiment 3. As shown in FIG.

In the following description in Embodiment 3, the external time acquired from the PTP master is called an external PTP time. The UN time converted from the external PTP time is called the external UN time. The UN time converted from the external UN time is called the native UN time.

A process in which the time synchronization device 10 according to the third embodiment synchronizes the time of the internal clock 14 with the external PTP time of the PTP master will be described with reference to Figs. 15 and 16 .

As will be described below, the processing of setting the external PTP time in the NIC clock and the processing of converting the external PTP time indicated by the NIC clock into the UN time and setting it in the internal clock 14 operate in parallel.

(Step S71: Time acquisition processing)

The time acquisition unit 21 acquires the external PTP time from the PTP master that is the time transmission device 50 . The time acquisition unit 21 writes the acquired external PTP time into the main memory 15 .

(Step S72: NIC setting processing)

The internal clock setting unit 22 sets the external PTP time acquired in step S71 to the NIC clock built in the NIC 13 .

(Step S73: Time conversion processing)

The internal clock setting unit 22 reads the external PTP time indicated by the NIC clock. The internal clock setting unit 22 transmits the read external PTP time to the time converting unit 26 via the post-conversion acquisition unit 221 , and sets the external PTP time to a time within the management range of the internal clock 14 . Convert to native UN time.

(Step S74: Internal clock setting processing)

The internal clock setting unit 22 transmits the unique UN time converted in step S73 to the time management unit 23 to set the unique UN time in the internal clock 14 .

With reference to FIGS. 16 and 17, the time conversion process (step S73 of FIG. 15) according to Embodiment 3 is demonstrated.

(Step S81: Time transmission processing)

The internal clock setting unit 22 reads the external PTP time indicated by the NIC clock. The internal clock setting unit 22 transmits the external PTP time to the time converting unit 26 via the post-conversion acquisition unit 221 . The time conversion unit 26 acquires the transmitted external PTP time.

(Step S82: UN conversion processing)

The time conversion unit 26 converts the external PTP time acquired in step S81 into an external UN time.

As shown in Fig. 18, as the PTP time used in the PTP master, TAI (International Atomic Time), which does not consider leap seconds, is used as a time system. In contrast to this, the UN time uses UTC considering leap seconds as a time system. Therefore, when converting the PTP time to the UN time, it is necessary to perform the conversion in consideration of the leap second. However, unlike leap years, leap seconds occur irregularly.

Here, the difference between TAI and UTC is defined as UtcOffset. This UtcOffset is managed by a server external to the time synchronization device 10 . Then, the time conversion unit 26 converts the external PTP time into the external UN time by acquiring UtcOffset from the external server and subtracting UtcOffset from the external PTP time.

(Step S83: Unique conversion processing)

The time conversion unit 26 converts the external UN time into a unique UN time by adding the conversion time to the external UN time converted and obtained in step S82. Specifically, the time conversion unit 26 converts the external UN time into a unique UN time that is a time within the management range of the internal clock 14 by adding the conversion time.

(Step S84: Time return processing)

The time conversion unit 26 transmits the unique UN time converted in step S83 to the post-conversion acquisition unit 221 . The internal clock setting unit 22 acquires the transmitted unique UN time via the post-conversion acquisition unit 221 .

Thereby, the unique UN time is set in the internal clock 14 in step S74 of FIG.

That is, irregular fluctuations that are irregular fluctuations in time may occur between the intrinsic time and the external time. Here, the irregular fluctuation is a leap second. In this way, when irregular fluctuations occur, the time conversion unit 26 specifies the time to fluctuate due to the irregular fluctuations, converts the external time only for the specified period of time, and calculates the unique time.

The inverse time transformation processing according to the third embodiment is the same as the inverse time transformation processing according to the second embodiment described with reference to FIG. 13 .

***Effect of Embodiment 3 ***

As described above, in the time synchronizing device 10 according to the third embodiment, between the time system used in the time synchronizing device 10 and the time system used in the time transmission device 50, irregular fluctuations such as leap seconds Even when this occurs, an appropriate conversion is possible.

10: time synchronizer 11: clock transmitter
12: processor 13: NIC
14: internal clock 15: main memory
16: peripheral device 21: time acquisition unit
22: internal clock setting unit 221: acquisition unit after conversion
23: time management unit 24: internal clock reference unit
241: acquisition unit after inverse transformation 25: time use unit
26: time conversion unit 27: time inverse conversion unit
40: visual conversion device 50: visual transmission device
51: external clock 61: transmission path
62: transmission path

Claims (8)

a time acquisition unit for acquiring an external time that is the time of an external clock;
Transmitting the external time acquired by the time acquisition unit to a time conversion device, when the external time is a time outside the management range of the internal clock, the external time is converted into a unique time that is a time within the management range of the internal clock and an internal clock setting unit that sets the unique time to the internal clock
A time synchronization device comprising a. The method of claim 1,
The internal clock is a time synchronization device that maintains an interval between the external time and the predetermined time. 3. The method of claim 1 or 2,
The internal clock is a time synchronization device that operates within the range of time management variables of a 32-bit version of Linux (registered trademark). The method of claim 1,
The time synchronization device,
Internal clock reference for converting the internal time into a reference time by transmitting the internal time, which is the time indicated by the internal clock, to the time conversion device, and performing a reverse process of the process for converting the external time into the unique time wealth
A time synchronization device further comprising a. 3. The method according to claim 1 or 2,
Let the difference between the external time and the intrinsic time be a conversion time,
The conversion time is set so that the number of periodic fluctuations that are periodic fluctuations of the time not caused by the external time system is equal
visual synchronizer. 4. The method of claim 3,
The intrinsic time is obtained by converting the external time by the amount of time that fluctuates due to the irregular fluctuations when irregular fluctuations that are irregular fluctuations in time occur between the intrinsic time and the external time
visual synchronizer. The time acquisition unit acquires the external time that is the time of the external clock,
an internal clock setting unit transmits the external time to a time conversion device to convert the external time into a unique time that is a time within the management range of the internal clock when the external time is outside the management range of the internal clock; Setting a unique time on the internal clock
Visual Synchronization Method. a time acquisition process for acquiring an external time that is the time of an external clock;
Sending the external time acquired by the time acquisition processing to a time conversion device, when the external time is a time outside the management range of the internal clock, the external time is converted into a unique time that is a time within the management range of the internal clock and internal clock setting processing to set the unique time to the internal clock
A time synchronizing program stored in a recording medium for causing a computer to function as a time synchronizing device that performs

Images