JP2019159899A - Time synchronization system, time synchronization method, and time synchronization program - Google Patents

Abstract

To provide a time synchronization system capable of performing time synchronization with high accuracy.SOLUTION: A time synchronization system includes: a server 600 for accumulating and analyzing sensor data; a plurality of sensor devices 100, 101, ... that respectively measure sensor data and transmit the data to the server 600; and an external power supply 200 that can supply a power supply voltage to each of the sensor devices 100, 101, ... and change the power supply voltage to be supplied to any voltage level. Each of the sensor devices 100, 101, ... establishes time synchronization with other sensor devices by setting the time to zero second in the initial state, triggered by detecting that the power supply voltage for an own sensor device has been changed from a predetermined voltage level to an optionally preset voltage of a transition destination, in the power-on state where the external power supply 200 is supplied with a power supply voltage of the predetermined level designated in advance for the own sensor device.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a time synchronization system, a time synchronization method, and a time synchronization program that synchronize time held by each of sensor devices installed at a plurality of locations of a measurement target with high accuracy.

  A plurality of sensor devices are installed on a measurement target and the measurement target is measured. As described above, there are attempts to confirm the operation status of the measurement target or to develop failure maintenance by installing a plurality of sensor devices on the measurement target. For this purpose, it is necessary to implement a function capable of measuring the measurement target by synchronizing the time of each sensor device. As described above, as a technique for measuring the measurement target by synchronizing the time of each sensor device, a method of matching the time synchronization between the sensor devices using a network protocol is generally used. Further, it is also described in Japanese Patent Application Laid-Open No. 2017-96651 “Time synchronization method, vibration sensor, vibration detection device, program and recording medium” of Patent Document 1. However, when wireless communication is used as a communication means with the receiver side, it is affected by noise in the operating environment and radio wave interference, and it is difficult to match the time synchronization between sensor devices using a network protocol. there were. And in the technique of patent document 1, since a synchronous time is calculated from the return | turnback vibration wave produced between different vibration sensors, it cannot utilize in the environment where a to-be-measured object differs.

JP 2017-96651 A

  As described above, the current technology described in Patent Document 1 related to the present invention has the following problems to be solved.

  When performing time synchronization utilizing wireless communication, it is difficult to realize time synchronization with high accuracy in milliseconds because of the influence of noise and radio wave interference. In addition, when using a time synchronization method by detecting power reactivation, it is necessary to perform power reactivation every time time synchronization is performed, and thus stable system operation cannot be realized.

  Further, the sensor device is usually provided with an RTC (Real Time Clock) function, but in many cases, different time information is held between the sensor devices. Further, if time information is exchanged in order to synchronize the time between the sensor devices, a delay time due to communication occurs, so that time synchronization cannot be realized with high accuracy. In addition, as described above, the technique described in Patent Document 1 calculates the synchronization time from the folded vibration wave generated between different vibration sensors, and thus cannot be used in an environment where the measurement target is different.

  Due to the above problems, even if sensor devices are installed at multiple locations and sensor data is acquired at each location, it is difficult to synchronize the time held by each sensor device. I can't. Such a sensor device can be used as an application for analyzing a single sensor data, but is not suitable for an application for accumulating a plurality of sensor data and analyzing them in a complex manner. Therefore, there has been a limit when used for the purpose of condition monitoring and failure maintenance.

(Object of the present invention)
The present disclosure has been made in view of such a problem, and an object thereof is to provide a time synchronization system, a time synchronization method, and a time synchronization program capable of performing time synchronization with high accuracy.

  In order to solve the above-described problems, the time synchronization system, the time synchronization method, and the time synchronization program according to the present invention mainly adopt the following characteristic configuration.

(1) A time synchronization system according to the present invention includes:
A server for storing and analyzing sensor data;
Based on an instruction from the server, each of the sensor data is measured and transmitted to the server;
An external power source capable of supplying a power supply voltage to each of the sensor devices and changing a voltage level of the supplied power supply voltage based on an instruction from the server;
Each of the sensor devices is
In a power-on state in which a power supply voltage of a predetermined voltage level is supplied, the external power supply changes the power supply voltage for its own sensor device from the predetermined voltage level to the voltage level of the transition destination based on an instruction from the server. When this is detected, the time is set to 0 seconds in the initial state, and time synchronization with the other sensor devices is performed.

(2) A time synchronization method according to the present invention includes:
A server for storing and analyzing sensor data;
Based on an instruction from the server, each of the sensor data is measured and transmitted to the server;
In a time synchronization system comprising: an external power supply that supplies a power supply voltage to each of the sensor devices based on an instruction from the server and can change a voltage level of the power supply voltage to be supplied. The sensor data measurement timing of each of the sensor devices is synchronized in time,
Each of the sensor devices is
In the power-on state where the power supply voltage of a predetermined voltage level is supplied, the external power supply changes the power supply voltage for the sensor device from the predetermined voltage level to the voltage level of the transition destination based on an instruction from the server. When this is detected, the time is set to 0 seconds in the initial state, and time synchronization with the other sensor devices is performed.

(3) A time synchronization program according to the present invention includes:
A server for storing and analyzing sensor data;
Based on an instruction from the server, each of the sensor data is measured and transmitted to the server;
An external power source capable of supplying a power supply voltage to each of the sensor devices based on an instruction from the server and capable of arbitrarily changing a voltage level of the power supply voltage to be supplied;
A process of synchronizing the measurement timing of the sensor data of each of the plurality of sensor devices is executed by a computer mounted on the sensor device,
Each of the sensor devices is
In a power-on state in which a power supply voltage of a predetermined voltage level is supplied, it is detected that the power supply voltage for the self-sensor device has been changed from the predetermined voltage level to the destination voltage level based on an instruction from the server As a trigger, the time is set to 0 seconds in the initial state, and time synchronization with other sensor devices is achieved.

  According to the time synchronization system, the time synchronization method, and the time synchronization program of the present invention, the external power supply that supplies the power supply voltage to each of the plurality of sensor devices is provided, and the power supplied from the external power supply to each sensor device. Since the time is synchronized among a plurality of sensor devices triggered by the time when it is detected that the voltage value has been changed to an arbitrarily determined voltage value, the following effects can be mainly achieved. That is, it is possible to reliably synchronize the time between a plurality of sensor devices, and simultaneously start sensing data measurement in each sensor device, and the sensor data measured in synchronization by each sensor device is converted into the sensor data. It is possible to realize sensor data acquisition control such as transmission to a server that stores and analyzes data.

Explains how the power supply voltage transition signal is output when it is detected that the sensor device of the time synchronization system according to the present invention has transitioned to a power supply voltage level that is arbitrarily determined in advance based on an external time synchronization command. It is explanatory drawing for doing. It is a system configuration diagram showing an example of a specific system configuration of a time synchronization system according to the present invention. FIG. 3 is an apparatus configuration diagram illustrating an example of an internal block configuration of the sensor device illustrated in FIG. 2. It is explanatory drawing for demonstrating an example of the operation | movement which controls the sampling number at the time of monitoring the transition of the voltage level of a power supply voltage in the power supply monitoring part of the sensor device shown in FIG. It is explanatory drawing for demonstrating a mode when the power supply voltage of the sensor device shown in FIG. 3 fluctuates instantaneously. It is a time chart which shows an example of the specific operation | movement of the time synchronization system shown in FIG.

  Preferred embodiments of a time synchronization system, a time synchronization method, and a time synchronization program according to the present invention will be described below with reference to the accompanying drawings. In the following description, the time synchronization system and the time synchronization method according to the present invention will be described. However, the time synchronization method may be implemented as a time synchronization program executable by a computer, or the time synchronization may be performed. Needless to say, the program may be recorded on a computer-readable recording medium. In addition, it is needless to say that the drawing reference numerals attached to the following drawings are added for convenience to the respective elements as an example for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiments. Yes.

<Features of the present invention>
Prior to the description of the embodiments of the present invention, an outline of the features of the present invention will be described first. In the present invention, when time information from a GPS (Global Positioning System) or a radio timepiece cannot be received, it is difficult to use a protocol such as NTP (Network Time Protocol) or RTP (Real-time Transport Protocol) of the network. However, the main feature is that the times of the plurality of sensor devices are synchronized with each other in response to the transition of the power supply voltage level without turning on the power again. In other words, the present invention includes an external power supply that supplies a power supply voltage in common to each of a plurality of sensor devices, and triggered by the time at which each sensor device detects a level transition of the power supply voltage value supplied from the external power supply. The main feature is that the time is simultaneously set to the initial value and synchronized among a plurality of sensor devices.

  This will be described in more detail as follows. FIG. 1 outputs a power supply voltage transition signal when it is detected in the sensor device of the time synchronization system according to the present invention that a transition to a power supply voltage level of a transition destination arbitrarily determined in advance based on a time synchronization command from the outside is detected. It is explanatory drawing for demonstrating a mode to do. An external power supply that supplies a power supply voltage to each sensor device in common changes the level of the power supply voltage supplied to each sensor device at the same timing. In each sensor device, the power supply monitoring function is used to monitor the level transition of the power supply voltage from the external power supply.

  When each sensor device detects a transition to an arbitrary power supply voltage as shown in FIG. 1 (in the case of FIG. 1A, it detects a transition from 3.3 V to a power supply voltage of 5 V). In the case of FIG. 1B, when it is detected that the power supply voltage has changed from 5 V to 3.3 V), a power supply voltage transition signal is output to notify that. Thus, by setting the reference time using the power supply voltage transition signal as a trigger, it is possible to realize time synchronization with high accuracy in units of milliseconds, for example, among a plurality of sensor devices.

<Configuration Example of Embodiment of the Present Invention>
(System configuration example of the time synchronization system according to the present invention)
Next, an example of a specific system configuration of the time synchronization system according to the present invention will be described in detail with reference to the system configuration diagram of FIG. FIG. 2 is a system configuration diagram showing an example of a specific system configuration of the time synchronization system according to the present invention.

  In the time synchronization system shown in FIG. 2, a plurality of external power sources 200 and 210, a large number of sensor devices 100, 101,..., 107, 110, 111,. An edge gateway 500 and a server 600 are included at least. The function of each component will be described below.

  The external power supplies 200 and 210 are DC-stabilized power supplies that can be programmed, respectively, and based on an external power control signal from the edge gateway 500, the sensor devices 100, 101,..., 107, 110, 111,. , 117, a power supply voltage of a predetermined voltage level determined in advance, or a transition of the power supply voltage from the predetermined voltage level to an arbitrarily designated transition destination voltage level at an arbitrary timing, or a transition The power supply can arbitrarily set the rise time and the fall time, and further can set the sequence operation. As the external power sources 200 and 210, any power source may be used as long as it has the same function as described above.

  The sensor devices 100, 101,..., 107, 110, 111,..., 117 each have functional blocks such as an MCU (microprocessor), a sensor, and a wireless module, and power from external power sources 200 and 210. Operates in response to supply and power supply voltage transitions. The main functions of the sensor devices 100, 101,..., 107, 110, 111,..., 117 synchronize each other's time, and the data sensed by the sensors provided therein are the data from the receivers 400 and 410. In response to the request, it is transmitted from the wireless module to the requesting receivers 400 and 410. The MCU (microprocessor) controls each functional block in each of the sensor devices 100, 101,..., 107, 110, 111,. Further details of the sensor devices 100, 101, ..., 107, 110, 111, ..., 117 will be described later.

  Based on the data request instruction from the edge gateway 500, the receivers 400 and 410 make data requests regarding sensing data to the sensor devices 100, 101,..., 107, 110, 111,. Sensing data transmitted from each of the devices 100, 101, ..., 107, 110, 111, ..., 117 is received and transmitted to the edge gateway 500 that has transmitted the data request instruction.

  The edge gateway 500 transmits a data request instruction regarding sensing data to the receivers 400 and 410 based on the data request instruction from the server 600, and the sensing data received from the receivers 400 and 410 is used as a data request. It transmits to the server 600 that sent the instruction. Further, when the time synchronization command is received from the server 600, an external power control signal is transmitted to the external power sources 200 and 210, and the sensor devices 100, 101,. , 111,..., 117 are controlled for setting the power supply voltage value to be supplied, the voltage level at which the power supply voltage is transitioned, the timing for the transition, and the like.

  The server 600 transmits a data request instruction regarding sensing data to the edge gateway 500, and the sensing data of each of the sensor devices 100, 101, ..., 107, 110, 111, ..., 117 transmitted from the edge gateway 500. Accumulate. The server 600 has a function of analyzing the stored sensing data of each sensor device 100, 101,..., 107, 110, 111,. The server 600 also has a function of sending a time synchronization command to the edge gateway 500.

(Sensor device configuration example)
Next, an example of the internal configuration of each of the sensor devices 100, 101, ..., 107, 110, 111, ..., 117 shown in FIG. 2 will be described with reference to the apparatus configuration diagram of FIG. The sensor devices 100, 101,..., 107, 110, 111,..., 117 all have the same internal configuration, and therefore the case of the sensor device 100 will be described as an example here. FIG. 3 is an apparatus configuration diagram illustrating an example of an internal block configuration of the sensor device 100 illustrated in FIG. 2.

  As illustrated in FIG. 3, the sensor device 100 includes at least an MCU 20, a sensor 21, and a wireless module 22. The MCU 20 includes at least a time synchronization unit 10 and a control unit 11 inside, and the time synchronization unit 10 includes at least a power supply monitoring unit 1 and a time management unit 2 inside.

  The MCU 20 is equipped with functions such as an ADC (Analog-to-Digital Converter), a counter, and an RTC (Real Time Clock). The time synchronization unit 10 of the MCU 20 is a block that realizes time synchronization. The power supply monitoring unit 1 provided in the time synchronization unit 10 periodically monitors the value of the power supply voltage supplied from the external power supply 200 at a predetermined time interval (at a time interval of at least 135 μs). Yes. The power supply monitoring unit 1 of the time synchronization unit 10 has a power supply monitoring function that converts analog data of the power supply voltage supplied from the external power supply 200 into digital data using the ADC function and monitors the voltage level of the power supply voltage. The power supply voltage value is monitored at predetermined time intervals using the power supply monitoring function.

  In addition, the power supply monitoring unit 1 of the time synchronization unit 10 measures the duration during which the same power supply voltage value continues using the counter of the MCU 20. When the power supply monitoring unit 1 detects a transition of the power supply voltage from the external power supply 200 (change from a power supply voltage at a predetermined voltage level determined in advance as a power-on state to a voltage level at a transition destination arbitrarily determined), A power supply voltage transition signal is output to the time management unit 2.

  The time management unit 2 in the time synchronization unit 10 of the MCU 20 performs time management triggered by the time when the power supply voltage transition signal is received from the power supply monitoring unit 1. That is, the measurement of time information is started with the reception of the power supply voltage transition signal. Here, regarding the time information measurement operation, the time information is measured, for example, every 100 ms using an internal clock using an RTC that is provided as a chip in the MCU 20 and implements a time holding function. When the time request is received from the control unit 11, the time management unit 2 outputs the measured time information to the request source control unit 11 in response to the time request.

  Further, the MCU 20 is integrated with a serial communication interface for controlling various sensors 21 and the wireless module 22. When receiving a data request regarding sensor data from the receiver 400, the wireless module 22 transmits a sensor data acquisition request to the control unit 11. When receiving a sensor data acquisition request from the wireless module 22, the control unit 11 sends a sensor data acquisition start command to the sensor 21. Upon receiving a sensor data acquisition start command from the control unit 11 of the MCU 20, the sensor 21 acquires sensor data, converts the acquired sensor data into digital data, and transmits the digital data to the control unit 11.

  The control unit 11 adds the time information acquired from the time management unit 2 to the sensor data received from the sensor 21 and transmits the sensor data to the wireless module 22. When the wireless module 22 receives the sensor data to which the time information is added from the control unit 11, the wireless module 22 transmits the sensor data with the time information to the receiver 400 that is the transmission source of the data request regarding the sensor data.

<Description of Operation of Embodiment of the Present Invention>
Next, an example of the operation of the time synchronization system shown in FIGS. 2 and 3 will be described as an embodiment of the present invention.

  First, an example of the operation of the time synchronization system shown in FIG. 2 will be described with reference to the explanatory diagram of FIG. In the explanatory diagram of FIG. 1A, when power is supplied from the external power supply 200 to the sensor device 100 at time t0, the power supply voltage of the sensor device 100 gradually increases, and the power supply voltage is designated at time t1. The predetermined voltage level rises to 3.3V, for example. Thereafter, the power supply voltage of the sensor device 100 enters a power-on state in which the predetermined voltage level, for example, 3.3 V is maintained. When receiving a time synchronization command from the server 600 in such a power-on state, the edge gateway 500 outputs an external power control command to the external power source 200 in response to the time synchronization command. As a result, at time t2, the external power supply 200 starts an operation of changing the power supply voltage level supplied to the sensor device 100 to an arbitrarily determined transition destination voltage level, for example, 5V.

  Thereafter, at time t3, when the power supply voltage of the sensor device 100 supplied from the external power supply 200 transitions to a voltage level of a transition destination that is arbitrarily determined, for example, 5 V, the power supply monitoring unit 1 in the time synchronization unit 10 of the sensor device 100. , It is detected that the power supply voltage has risen from a predetermined voltage level determined in advance as a power-on state, for example, 3.3 V, and has transitioned to a voltage level of an arbitrarily determined destination, for example, 5 V. As a result, the power supply monitoring unit 1 outputs a power supply voltage transition signal to the time management unit 2. The time management unit 2 performs time management so that time synchronization with other sensor devices can be obtained at a predetermined timing after the time t3 when the power supply voltage transition signal is received from the power supply monitoring unit 1. Do.

  When the power cable length from the external power source 200 to the sensor device 100 is different from the power cable lengths of other sensor devices, the power supply voltage differs between the sensor devices or the power supply voltage level. Therefore, it is considered that the lengths of the power cables between the sensor devices and the external power source 200 are aligned with each other in advance.

  In addition, since the effects of power supply noise and instantaneous voltage fluctuations are assumed, the following measures are taken. FIG. 4 is an explanatory diagram for explaining an example of an operation for controlling the number of samplings when the power supply monitoring unit 1 of the sensor device 100 shown in FIG. 3 monitors the transition of the voltage level of the power supply voltage. That is, in FIG. 4, after the power supply monitoring unit 1 detects a change of a power supply voltage set in advance as a power-on state to a predetermined voltage level, for example, 5 V, and the power supply voltage is a predetermined limit time. When it is detected that the voltage level of the transition destination is continuously changed (changed) to a different voltage level arbitrarily determined for a duration Tc of T or more, for example, 500 ms or more, the power supply voltage is monitored. An example of a state in which the sampling time interval to be performed is shortened from a normal time interval to a predetermined time interval so as to increase the number of samplings is shown.

  In the explanatory diagram of FIG. 4, the circles indicate sampling points for monitoring the power supply voltage. As shown in the explanatory diagram of FIG. 4, the power supply voltage does not change from the same voltage level after detecting that the power supply voltage is set to a predetermined voltage level of a preset power supply voltage, for example, 5V, or the time Even if the power supply voltage has changed at t4 (for example, changed from 5V to 3.3V), the duration Tc during which the power supply voltage has transitioned (changed) is less than the predetermined limit time T, for example, less than 500 ms. In this case, the mutual time interval between the sampling points for monitoring the power supply voltage continues the normal time interval T0.

  However, the duration Tc from time t4 when the power supply voltage has changed (that is, from a predetermined voltage level set in advance as a power-on state, for example, from 5V to an arbitrarily determined transition destination voltage level, for example, 3.3V) is the limit. If it is detected that the state in which the power supply voltage is transitioned (changed) continues until time t5 when the time T is equal to or greater than 500 ms, for example, is reached, control is performed as follows. That is, thereafter, the sampling time interval between the sampling points for monitoring the power supply voltage is shortened to a time interval T1 that is predetermined as a time interval shorter than the time interval T0 in the normal case, and the number of samplings per unit time Increase. Thus, it is possible to cope with an instantaneous change in the power supply voltage.

  As shown in the explanatory diagram of FIG. 4, the state in which the power supply voltage is shortened to the time interval T1 is designated toward a predetermined voltage level, for example, 5V, set in advance as a power-on state from the time t5 is reached. Even if the voltage gradually rises in accordance with the rise time Δt, the protection time tg is arbitrarily set in advance as the protection time tg after the voltage level, for example, 5 V, as well as the rise time Δt until the voltage level, for example, 5 V is reached. Continue until the elapses.

  Then, it is detected that the power supply voltage has not changed from the preset predetermined voltage level, for example, 5V after the protection time tg elapses and reaches the time t6 after reaching the preset predetermined voltage level, for example, 5V. When continuing, the mutual sampling time interval between the sampling points monitoring the power supply voltage is returned from the short time interval T1 to the time interval T0 in the original normal state.

  Thus, the influence of power supply noise and the influence of instantaneous voltage fluctuations are eliminated, and the voltage of the power supply voltage is reached at a time point t6 shown in FIG. 4, for example, when a stable state is reached in which the voltage level of the power supply voltage does not change. It can be reliably detected that the level has returned to a predetermined voltage level set in advance, for example, 5V.

  FIG. 5 is an explanatory diagram for explaining a state in which the power supply voltage of the sensor device 100 shown in FIG. 3 varies instantaneously. For example, at time t7 and time t8, the power supply voltage The case where the instantaneous fluctuation | variation of the voltage level has generate | occur | produced is shown. As shown in FIG. 5, when an instantaneous power supply voltage fluctuation of, for example, less than 100 ms occurs at time t7 or time t8, the power supply monitoring unit 1 of the sensor device 100 has a power supply voltage of 3.3V. Since the state at the voltage level is monitored at a sampling point having a short time interval T1, for example, a time interval of 50 ms, instantaneous fluctuations in the power supply voltage occurring at time t7 and time t8 can be reliably recognized.

  Therefore, it is possible to reliably avoid erroneous operation by erroneously determining that a transition of the power supply voltage to a predetermined voltage level that has been set in advance has occurred in such a momentary voltage fluctuation. Furthermore, since the transition of the power supply voltage can be confirmed with a finer time accuracy, the time synchronization accuracy between the sensor devices can be further increased. In order to reduce the effects of power supply noise and instantaneous voltage fluctuations, the external power supply 200 may set the rise time and fall time of the power supply voltage gently based on an instruction from the server 600. It is valid.

  Next, an example of a specific operation of the time synchronization system shown in FIG. 2 will be described in detail with reference to the time chart of FIG. FIG. 6 is a time chart showing an example of a specific operation of the time synchronization system shown in FIG. 2, in which the horizontal axis indicates time (Time), and the vertical axis indicates the server 600, the edge gateway 500, and the external power source 200. . A receiver 400, a sensor device 100 and a sensor device 101 for time synchronization are illustrated. The time chart of FIG. 6 shows the state transition from when the time synchronization command is sent from the server 600 to the edge gateway 500 until the time synchronization between the time synchronization target sensor device 100 and the sensor device 101 is performed, and The state transition from when the data request instruction is sent from the server 600 to the edge gateway 500 until the transmission of the sensor data of the measurement results in the sensor device 100 and the sensor device 101 is shown.

  In the description of the time chart of FIG. 6, as shown in FIG. 1B and FIG. 4, in the power-on state in which the predetermined voltage level of the preset power supply voltage is set to 5 V, for example, the sensor device 100, In order to synchronize the time of the sensor device 101, the power supply voltage is transitioned from the predetermined power level 5 V to a voltage level 3.3 V arbitrarily set for the sensor device 100 and the sensor device 101 from the external power source 200. The case of supplying in the following will be described.

  In the time chart of FIG. 6, first, at a time ta, after setting to a power-on state in which a power supply voltage of a predetermined voltage level of 5 V is supplied from the external power supply 200 to the sensor device 100 and the sensor device 101, At tb, a time synchronization command is transmitted from the server 600 to the edge gateway 500 in order to perform time synchronization between the sensor device 100 and the sensor device 101.

  The edge gateway 500 receives the time synchronization command from the server 600 as an opportunity, and at time tc, the transition destination arbitrarily determined from the predetermined voltage level 5 V determined in advance from the edge gateway 500 to the external power source 200. An external power supply control signal instructing the transition of the power supply voltage to the voltage level of 3.3 V is transmitted to start power supply control of the external power supply 200.

  When the external power supply 200 receives the external power supply control signal from the edge gateway 500 at time tc, first, the external power supply 200 supplies the power supply voltage supplied to each sensor device, for example, the sensor device 100 and the sensor device 101, to the power supply voltage. For a control of the time interval of the sampling point for monitoring the time Tc, a predetermined voltage level, eg, 5 V, is changed from a preset voltage level, eg, 5 V, for a predetermined duration (eg, 500 ms). ) Here, the external power source 200 has a value of the predetermined voltage level, for example, 5 V, the voltage level of the transition destination, for example, 3.3 V, a fall time from the predetermined voltage level to the voltage level of the transition destination, or the duration Tc. Can be set to an arbitrary value according to the external power supply control signal from the edge gateway 500, that is, according to an instruction (time synchronization command) from the server 600.

  After that, when the duration Tc, for example, 500 ms elapses, the external power supply 200 again supplies the power supply voltage supplied to each sensor device, for example, the sensor device 100 and the sensor device 101, with the rise time Δt specified in advance. The voltage level at the transition destination, for example, 3.3V is changed (transitioned) from the preset predetermined voltage level, for example, 5V. That is, at time td (= tc + Tc + Δt), the power supply voltage supplied to each sensor device, for example, the sensor device 100 and the sensor device 101 is changed from the voltage level at the transition destination, for example, 3.3V to the original predetermined voltage level, for example, 5V. (Transition). Here, the external power source 200 also uses the transition time from the voltage level of the transition destination, for example, 3.3 V to the predetermined voltage level, for example, 5 V, in accordance with the external power control signal from the edge gateway 500, that is, The value can be set to an arbitrary value in accordance with an instruction (time synchronization command) from the server 600.

  Thereafter, in each sensor device, for example, the sensor device 100 and the sensor device 101, the power supply monitoring unit 1 detects that the power supply voltage has again reached a predetermined voltage level, for example, 5V set in advance as a power-on state at time td. To do. As a result, the power supply voltage transition signal is output from the power supply monitoring unit 1 to the time management unit 2 in each sensor device, for example, the sensor device 100 and the sensor device 101. Accordingly, the time management units 2 of the sensor devices, for example, the sensor device 100 and the sensor device 101, are arranged at the timing of the time td, that is, at the timing when the power supply voltage reaches the preset voltage level, for example, 5V again. Time management is performed by setting time information of devices such as the sensor device 100 and the sensor device 101 to 0 seconds in the initial state.

  That is, each of the sensor devices, for example, the sensor device 100 and the sensor device 101, has a timing at time td (= power supply voltage control start time tc + continuation time Tc (for example, 500 ms) + rise time Δt), that is, power supply voltage control start time. From tc, it is detected that the power supply voltage has again reached a predetermined voltage level set in advance, for example, 5 V, at time td when the time specified by the server 600 has elapsed as the duration Tc and the rise time Δt, As a result, the time synchronization state is set to 0 seconds in the initial state.

  In the above description, the case where the voltage level rises from the transition destination voltage level of 3.3 V to the predetermined voltage level of 5 V as a trigger for time synchronization has been described. However, the same applies to the case where the voltage level of the transition destination is higher than the predetermined voltage level. In such a case, the fall time is used instead of the rise time Δt.

  On the other hand, in the server 600 as well, after the edge gateway 500 outputs the external power control signal from the time tb at which the time synchronization command is transmitted in order to hold the time information of each sensor device, for example, the sensor device 100 and the sensor device 101, Time management is performed from the timing when the time of (continuation time Tc + rise time Δt) has elapsed. Regarding the timing for starting the time management, a time lag occurs due to the communication transmission time between each sensor device, for example, the sensor device 100, the sensor device 101, and the server 600, but the time lag is so small that it can be ignored. This time is not particularly considered here.

  Next, when the server 600 issues a data request instruction regarding sensor data to each sensor device, for example, the sensor device 100 and the sensor device 101, first, at time te, the sensor data of each sensor device is sent to the edge gateway 500. A data request instruction including the designation of the measurement start timing (for example, the measurement start of sensor data at x seconds (= td + x) after time td at which the synchronization setting of time 0 seconds in the initial state is performed) is transmitted. The edge gateway 500 sends the data request instruction received from the server 600 to the receiver 400. The receiver 400 instructs each sensor device, for example, the sensor devices 100, 101, to receive a data request received from the edge gateway 500 (for example, instruct to start measuring sensor data x seconds after the time td (= td + x)). Send out a data request based on wireless communication.

  When each of the sensor devices, for example, the sensor devices 100 and 101 receives the data request from the receiver 400, the sensor devices 100 and 101 are aligned in time synchronized with each other from x seconds (= td + x) after the designated time td. Start measuring data. Then, the measured sensor data is sent to the request instruction source server 600 via the receiver 400 and the edge gateway 500. Thereafter, when the time tf at which the measurement is finished is reached, each sensor device, for example, the sensor devices 100 and 101 finishes the measurement.

  Through the operation as described above, each sensor device, for example, the sensor devices 100 and 101 measures the sensor data in a state in which the time synchronization between them is ensured, and the server 600 that accumulates and analyzes the sensor data Can be sent.

(Explanation of effect of embodiment)
As described in detail above, in this embodiment, it is possible to reliably synchronize the time between a plurality of sensor devices, and each sensor device starts measuring sensing data at the same time. It is possible to realize sensor data acquisition control in which sensor data measured in synchronization with each other is transmitted to the server 600 that stores and analyzes the sensor data.

  As an example different from the above embodiment, a specific pattern (for example, 3.3 V → 5 V → 3.3 V) in which the voltage level of the power supply voltage supplied to each sensor device is changed in advance at predetermined time intervals. By doing so, each sensor device may be reset by software.

  That is, each sensor device is provided with a mechanism for detecting that the voltage level of the power supply voltage has changed according to the specific pattern at the predetermined time interval, so that when each sensor device detects such a transition, A reset may be implemented in software, including resetting the time synchronization. By applying a mechanism such as this to a terminal that employs a strong waterproof housing or the like and cannot be provided with an external reset switch, resetting of a device such as a sensor device can be easily realized.

  The configuration of the preferred embodiment of the present invention has been described above. However, it should be noted that such embodiments are merely examples of the present invention and do not limit the present invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made according to a specific application without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Power supply monitoring part 2 Time management part 10 Time synchronization part 11 Control part 20 MCU
21 Sensor 22 Wireless module 200, 210 External power source 100, 101, ..., 107 Sensor device 110, 111, ..., 117 Sensor device 400, 410 Receiver 500 Edge gateway 600 Server T Limit time T0 Time interval T1 Time interval Tc Duration

Claims (10)

A server for storing and analyzing sensor data;
Based on an instruction from the server, each of the sensor data is measured and transmitted to the server;
An external power source capable of supplying a power supply voltage to each of the sensor devices and changing a voltage level of the supplied power supply voltage based on an instruction from the server;
Each of the sensor devices is
In a power-on state in which a power supply voltage of a predetermined voltage level is supplied, the external power supply changes the power supply voltage for its own sensor device from the predetermined voltage level to the voltage level of the transition destination based on an instruction from the server. Triggered by the fact that the time is detected, the time is set to 0 seconds in the initial state, and time synchronization with other sensor devices is performed. Each of the sensor devices is
The timing for setting the time to 0 seconds in the initial state is determined based on an instruction from the server from the time when the external power supply changes the power supply voltage for the sensor device from the predetermined voltage level to the voltage level of the transition destination. The preset duration for controlling the sampling time interval for monitoring the power supply voltage and the rise time of the preset voltage level as the elapsed time when returning from the transition destination voltage level to the predetermined voltage level The time synchronization system according to claim 1, wherein a time obtained by summing the falling time and the elapsed time is used as the elapsed timing. Each of the sensor devices is
From the time when the external power supply changes the power supply voltage for the self-sensor device from the predetermined voltage level to the voltage level of the transition destination, the duration of the power supply voltage for the self-sensor device is exceeded for a predetermined limit time or more. If the voltage level transition continues, set the sampling time interval for power supply voltage monitoring to a time interval shorter than the time interval in the normal state to increase the number of samplings for power supply voltage monitoring. The time synchronization system according to claim 2. Each of the sensor devices is
When the external power source detects that the voltage level of the power supply voltage to be supplied to the self-sensor device is changed at a predetermined time interval based on a predetermined pattern based on an instruction from the server. The time synchronization system according to any one of claims 1 to 3, wherein the sensor device is reset by software, including resetting the synchronization, to return to the initial state. A server for storing and analyzing sensor data;
Based on an instruction from the server, each of the sensor data is measured and transmitted to the server;
In a time synchronization system comprising: an external power supply that supplies a power supply voltage to each of the sensor devices based on an instruction from the server and can change a voltage level of the power supply voltage to be supplied. The sensor data measurement timing of each of the sensor devices is synchronized in time,
Each of the sensor devices is
In the power-on state where the power supply voltage of a predetermined voltage level is supplied, the external power supply changes the power supply voltage for the sensor device from the predetermined voltage level to the voltage level of the transition destination based on an instruction from the server. A time synchronization method characterized in that the time is set to 0 seconds in the initial state and the time synchronization with the other sensor devices is performed in response to the fact that this is detected. Each of the sensor devices is
The timing for setting the time to 0 seconds in the initial state is determined based on an instruction from the server from the time when the external power supply changes the power supply voltage for the sensor device from the predetermined voltage level to the voltage level of the transition destination. The preset duration for controlling the sampling time interval for monitoring the power supply voltage and the rise time of the preset voltage level as the elapsed time when returning from the transition destination voltage level to the predetermined voltage level The time synchronization method according to claim 5, wherein a time obtained by summing the fall time and the elapsed time is used as the elapsed time. Each of the sensor devices is
From the time when the external power supply changes the power supply voltage for the self-sensor device from the predetermined voltage level to the voltage level of the transition destination, the duration of the power supply voltage for the self-sensor device is exceeded for a predetermined limit time or more. If the voltage level transition continues, set the sampling time interval for power supply voltage monitoring to a time interval shorter than the time interval in the normal state to increase the number of samplings for power supply voltage monitoring. The time synchronization method according to claim 6. Each of the sensor devices is
When the external power source detects that the voltage level of the power supply voltage to be supplied to the self-sensor device is changed at a predetermined time interval based on a predetermined pattern based on an instruction from the server. The time synchronization method according to any one of claims 5 to 7, wherein the sensor device is reset by software, including resetting the synchronization, to return to the initial state. A server for storing and analyzing sensor data;
Based on an instruction from the server, each of the sensor data is measured and transmitted to the server;
An external power source capable of supplying a power supply voltage to each of the sensor devices based on an instruction from the server and capable of arbitrarily changing a voltage level of the power supply voltage to be supplied;
A process of synchronizing the measurement timing of the sensor data of each of the plurality of sensor devices is executed by a computer mounted on the sensor device,
Each of the sensor devices is
In a power-on state in which a power supply voltage of a predetermined voltage level is supplied, it is detected that the power supply voltage for the self-sensor device has been changed from the predetermined voltage level to the destination voltage level based on an instruction from the server As a trigger, the time is set to 0 seconds in the initial state, and time synchronization with the other sensor devices is performed. Each of the sensor devices is
The timing for setting the time to 0 seconds in the initial state is determined based on an instruction from the server from the time when the external power supply changes the power supply voltage for the sensor device from the predetermined voltage level to the voltage level of the transition destination. The preset duration for controlling the sampling time interval for monitoring the power supply voltage and the rise time of the preset voltage level as the elapsed time when returning from the transition destination voltage level to the predetermined voltage level The time synchronization program according to claim 9, wherein the total time of the fall time and the elapsed time are used as the elapsed timing.

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