Sensing device and remote sensing system

Abstract

To provide a sensing device and a remote sensing system capable of saving power consumption and improving the real time property of measurement even when using a sensor having a long measurement time.SOLUTION: The sensor device includes at least one sensor unit that performs measurement on a measurement target for a certain measurement time, a power supply line that supplies power to the sensor unit, a control unit that is intermittently activated and transmits measurement data to an external device, the control unit causing the sensor unit to start measurement and acquiring the measurement data from the sensor unit after completion of the measurement, and a timer to which time is set by the control unit and which notifies the control unit of elapse of the set time.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a remote sensing system used for various monitoring purposes in water supply and sewerage systems, social infrastructure, factories, offices, etc. [Background technology]

[0002] Remote sensing systems are used in social infrastructure such as water supply and sewerage, electricity, and gas, as well as in buildings and factories, to remotely monitor the environment, structural deterioration, the operating status of plants and production facilities, and the condition of installed equipment. The values, quantities, and indicators of the objects being observed (measured) range from common indicators such as temperature, humidity, and air pressure to various indicators, depending on the object being monitored, such as structural distortion, various displacements, distance to the monitored object, and, for facilities with fluid pipelines, flow velocity, wind speed, and flow rate in the pipelines, as well as hydrogen ion concentration (pH), turbidity, and gas concentration of the fluid. Sensors are used for each of these indicators. Furthermore, the observation (measurement) points of monitored objects are not always conveniently located for workers. The numerous sensor installation points can make it difficult to install power and communication cables, or the locations may be unsuitable for installing information equipment due to the risk of submersion or corrosion, or may simply be inaccessible to workers. In such cases, a remote sensing system is used in which only sensing devices (sensing nodes) or sensors that operate on limited power are placed at the observation (measurement) point, and measurement data (measurement results) are transmitted to a higher-level device (parent device, etc.) located in a remote location.

[0003] An example of the configuration of a conventional remote sensing system is shown in Figure 1. An example of a sensing system with such a configuration is the sensor network system disclosed in Japanese Patent Laid-Open No. 2018-147059, "Sensor Network System" (Patent Document 1).

[0004] Sensing devices 100-1, 100-2, and 100-3 are devices that periodically perform remote sensing using a sensor unit 102 mounted on each of them, and measurement commands and measurement data are exchanged with a host device 101 located in a remote location by wireless communication via a communication unit 103. In a remote sensing system equipped with multiple sensing devices 100 as in this example, avoiding collisions between signals (measurement data) sent by each sensing device, in other words, avoiding collisions in communication of measurement data between each sensing device and the host device 101, is an important issue, and avoiding collisions in communication of measurement data is necessary not only in wireless communication but also when sharing a wired communication medium such as electric wires or optical fiber.

[0005] 2 is a diagram showing an example of the operational states, contents, and timing of each sensing device and host device in the conventional remote sensing system described above. Fig. 2 shows an example in which a transmission delay is used as a method for avoiding collisions in communication between the sensing devices and the host device 101 and the measurement data transmitted by each sensing device. In this example, the host device 101 simultaneously transmits a time synchronization / measurement command to all sensing devices 100-1, 100-2, and 100-3, and upon receiving the measurement command, the control unit 104 inside each sensing device 100 simultaneously starts measurement using the sensor unit 102. If the sensing devices 100-1 to 100-3 simultaneously transmit measurement data to the host device 101 after completing the measurement, a communication collision will occur. Therefore, in this example, the control unit 104 avoids communication collisions by transmitting the measurement data to the host device 101 after a delay time that differs for each sensing device has elapsed. Specifically, where S is the data transmission time and d is the small margin of time, sensing device 100-1 transmits measurement data without delay, sensing device 100-2 transmits measurement data after a delay time (S + d) has elapsed, and sensing device 100-3 transmits measurement data after a delay time of (S + d) × 2 has elapsed. By transmitting data after a predetermined delay time has elapsed, communication collisions can be avoided. Furthermore, power consumption can be reduced by putting the sensing devices into a sleep state during the delay time. Note that in this example, sensing devices 100-1, 100-2, and 100-3 must all operate with the same measurement command, measurement time, and transmission time. In cases where the number of sensors installed in each sensing device or the measurement times of the sensors differ, implementation using time slots, as in the following conventional example, is more suitable.

[0006] Figure 3 shows another example of the operational status, content, and timing of each sensing device and the host device in a conventional remote sensing system. In this example, time slots #1, #2, and #3 are assigned to sensing devices 100-1, 100-2, and 100-3 in advance. Sensing devices 100-1, 100-2, and 100-3 receive measurement commands from host device 101 at the beginning of their assigned time slots, perform measurements using sensor unit 102, and return measurement data to the host device after completing the measurements, thereby preventing communication collisions. Furthermore, each sensing device can independently send and receive measurement commands and measurement results from host device 101, enabling flexible operation, such as changing the type of sensor installed and measurement content for each sensing device. Furthermore, sensing devices 100-1, 100-2, and 100-3 enter a sleep state after returning their measurement data and then wake up at the start of their own time slots triggered by a timer or the receipt of a measurement command, thereby saving power. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-147059 Summary of the Invention [Problem to be solved by the invention]

[0008] The first problem with conventional sensing devices and sensing systems is that a delay is required between measurement and data transmission to avoid collisions in measurement data communications, impairing the real-time nature of measurements. Specifically, in the example shown in Figure 2, the time from when a sensing device completes measurement until the measurement data is transmitted to a higher-level device varies depending on the sensing device. For example, sensing device 100-3 requires a maximum delay of (S+d) ​​× 2, resulting in a delay between when the sensing device completes measurement and when the higher-level device receives the measurement data. This delay becomes a major problem as data communication speeds slow and the number of sensing devices increases.

[0009] In the example using time slots shown in Figure 3, if the measurement time by the sensing device is less than the remaining time (= time slot length - command reception time - measurement data transmission time) obtained by subtracting the command reception time and measurement data transmission time from the time slot length, the measurement value can be sent to the host device immediately after measurement is completed, and the delay described above does not occur. However, if the sensor measurement time exceeds the remaining time, data transmission must be delayed until the device's next time slot, resulting in a significant delay and potentially impairing real-time performance. This delay time varies depending on the sensing device and sensing system, but for example, if the time slot length is 10 seconds and there are 30 sensing nodes, the maximum delay time is 5 minutes. This kind of delay is unacceptable for applications such as controlling mobile objects, social infrastructure, and production equipment, and can lead to problems such as control errors and malfunctions due to the delay.

[0010] The second issue is that if a sensor with a long measurement time is installed as the sensor unit within the sensing device, the power consumption of the sensing device increases. In both the examples shown in Fig. 2 and Fig. 3, the sensing device 100 needs to remain activated (powered on) while the sensor unit 102 is performing measurement, which increases the power required during that time. If the sensing device 100 operates on limited power such as from a battery, this increase in power consumption shortens the operating period of the sensing device, resulting in adverse effects such as increased frequency of battery replacement, shortened device life, and reduced measurement frequency.

[0011] The third issue is that when a sensing device equipped with a sensor with a long measurement time is incorporated (replaced or added) into an existing sensing system, operational timing, such as the exchange of measurement commands and measurement results and startup time, is disrupted, resulting in significant system modification efforts. For example, in the example shown in Figure 2, if only the sensor unit 102 of sensing device 100-1 is equipped with a sensor with a long measurement time, the measurement time of the sensor units 102 of the other sensing devices 100-2 and 100-3 must also be extended, necessitating additional modifications to the programs of the control units 104 of each sensing device. Furthermore, the time from when the upper device 101 first sends a measurement command until all sensing devices complete measurement (cycle time) becomes longer, resulting in significant performance degradation related to system specifications, such as a decrease in measurement frequency. Similarly, in the example shown in Figure 3, if only sensing device 100-1 is equipped with a sensor in sensor unit 102 whose measurement time exceeds the time slot length, the measurement results cannot be returned in the time slot in which the measurement command was received, and a large load will be generated, such as the need to modify the communication protocol between upper device 101 and sensing device 100.

[0012] Therefore, an object of the present invention is to provide a sensing device and a remote sensing system that solve the above-mentioned problems and can reduce power consumption and improve real-time measurement performance even when using a sensor with a long measurement time. [Means for solving the problem]

[0013] The present application includes multiple means for resolving at least part of the above-mentioned problems, and an example thereof is as follows: That is, a sensing system comprising a host device and one or more sensing devices connected to the host device, wherein the sensing device comprises at least one sensor unit that measures an object to be measured over a certain measurement time, a power line that supplies power to the sensor unit, a control unit that is activated intermittently and transmits measurement data to the host device, the control unit causing the sensor unit to start measurement and acquiring the measurement data from the sensor unit after measurement is completed, and a timer that is set by the control unit and notifies the control unit of the passage of the set time, wherein the control unit sets the time until the sensor unit is activated in the timer so that the measurement time of the sensor unit is completed before transmitting the measurement data. [Effects of the Invention]

[0014] The present invention has the effect of minimizing the delay time from the completion of measurement by the sensor unit in the sensing device until the measurement data is reported to the host device, thereby improving the real-time measurement performance even when using sensors with long measurement times. Furthermore, by shortening the startup time of the sensing device, power consumption is reduced, enabling the sensing device to operate for a long period of time using limited power. Furthermore, by matching the timing of measurement commands from the host device to each sensor with the transmission of measurement data from the sensing device, measurement data processing and device management are simplified, significantly reducing the load on the sensing device and the host device.

[0015] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a conventional remote sensing system. [Figure 2] 1 is a diagram showing an example of the operational states, contents, and timing of each sensing device and a higher-level device in a conventional remote sensing system. [Figure 3] 10A and 10B are diagrams illustrating other examples of the operational states, contents, and timings of each sensing device and a higher-level device in a conventional remote sensing system. [Figure 4] FIG. 1 is a diagram illustrating the configuration of a sensing device and a remote sensing system according to a first embodiment. [Figure 5] 5 is a diagram showing an example of the state, content, and timing of the operation of the sensing device and the higher-level device in the first embodiment. FIG. [Figure 6] FIG. 10 is a diagram illustrating the configuration of a sensing device and a remote sensing system according to a second embodiment. [Figure 7] 10A and 10B are diagrams illustrating an example of the state, content, and timing of the operation of the sensor unit, the sensing device, and the higher-level device in the second embodiment. [Figure 8] 10A and 10B are diagrams illustrating an example of a measurement command and measurement data in the second embodiment. [Figure 9] FIG. 10 is a diagram illustrating the configuration of a sensing device and a remote sensing system according to a third embodiment. [Figure 10] 10A and 10B are diagrams illustrating an example of the operational states, contents, and timings of the sensor unit, the sensing device, and the higher-level device in the third embodiment. [Figure 11] FIG. 10 is a diagram illustrating the configuration of a sensing device and a remote sensing system according to a fourth embodiment. [Figure 12] 10A and 10B are diagrams illustrating an example of the state, content, and timing of the operation of the sensor unit, the sensing device, and the higher-level device in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment is an example for explaining the present invention, and for clarity of explanation, appropriate omissions and simplifications have been made. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0018] The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings. When there are multiple components having the same or similar functions, they may be described using the same reference numeral with different subscripts. Furthermore, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0019] In the embodiments, processing performed by executing a program may be described. Here, a computer executes the program using a processor (e.g., a CPU or a GPU) and performs processing defined by the program using storage resources (e.g., a memory) and interface devices (e.g., a communication port). Therefore, the entity performing the processing by executing the program may be the processor. Similarly, the entity performing the processing by executing the program may be a controller, device, system, computer, or node having a processor. The entity performing the processing by executing the program may be any computing unit, and may include a dedicated circuit that performs specific processing. Here, the dedicated circuit may be, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a CPLD (Complex Programmable Logic Device).

[0020] A program may be installed on a computer from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server may include a processor and storage resources for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. In addition, in an embodiment, two or more programs may be realized as one program, or one program may be realized as two or more programs. [Example]

[0021] 4 is a diagram showing the configuration of a sensing device and a remote sensing system in the first embodiment. The remote sensing system in the first embodiment is made up of a host device 201 and sensing devices 200-1 and 200-2.

[0022] Sensing device 200-1 is equipped with two sensor units 204-1 and 204-2, each of which receives power from control unit 205 via power supply lines 203-1 and 203-2 and whose measurement operations are controlled by control unit 205 via sensor communication lines 202-1 and 202-2. A timer 206 and a power supply circuit 207 are provided inside sensing device 200-1. Timer 206 is connected to control unit 205 via timer communication line 208, allowing control unit 205 to set the timer time and to notify control unit 205 of the lapse of the set time. Note that while only the configuration of sensing device 200-1 is shown in FIG. 4, sensing device 200-2 also has a similar configuration.

[0023] Furthermore, the sensing devices 200-1 and 200-2 are connected to the host device 201 via a common communication medium 209. The communication medium 209 can be wireless communication, wired communication, optical fiber communication, or the like. In the case of wired communication, the communication medium 209 can have various configurations such as a bus type, a tree type, or a star type. In general, to simplify the configuration in a remote sensing system, a configuration is used in which the host device 201 is equipped with a pair of transceivers and communicates with the multiple sensing devices 200 via the common communication medium 209.

[0024] In FIG. 4, the control unit 205 is connected to the higher-level device 201 via the communication medium 209, but the control unit 205 may have an internal communication unit (communication interface) that performs communication according to the communication medium 209, or the control unit 205 may be connected to the communication medium 209 via a communication unit not shown (the same applies to the sensing device 200-2 and each sensing device in each of the following embodiments).

[0025] Sensing devices 200-1 and 200-2 intermittently start up for short periods (e.g., 1 second) at regular intervals (startup cycle (e.g., 1 minute)), receive measurement commands from a higher-level device, and repeat the operation of returning (transmitting) measurement data in response. For example, in sensing device 200-1, if the measurement time of sensor unit 204-1 is very short compared to the startup time of sensing device 200-1, sensor unit 204-1 starts measurement at the same time as receiving a measurement command from higher-level device 201, and returns the measurement data immediately after the measurement is completed. On the other hand, if the measurement time of sensor unit 204-1 is longer than the startup time of sensing device 200-1, even if sensor unit 204-1 starts measurement immediately upon receiving a measurement command from host device 201, the measurement may not be completed during the startup time or time slot of sensing device 200-1, and measurement data may not be able to be returned during that period. However, the sensing device in this embodiment is configured to be able to return measurement data during the startup time or time slot of the sensing device even if the measurement time of the sensor unit is long.

[0026] Hereinafter, the operation of sensing device 200-1 will be described on the assumption that the measurement time of sensor unit 204-1 is equal to or longer than the activation time or time slot of sensing device 200-1.

[0027] FIG. 5 is a diagram showing an example of the operational states, contents, and timing of the sensing device 200-1 and the host device 201 in the first embodiment. In FIG. 5, the control unit 205 of the sensing device 200-1 intermittently activates for a short period (e.g., one second) at regular intervals (activation cycle (e.g., one minute)) as described above, receives a measurement command from the host device 201, and repeats the operation of transmitting measurement data to the host device (or outputting measurement data to the host device). Furthermore, the sensor unit 204-1 is controlled by the control unit 205 and repeats the operation of performing measurement for a fixed measurement time. The control unit 205 supplies power to the sensor unit 204-1 via the power line 203-1, activates the sensor unit 204-1 to start measurement, and acquires the measurement data from the sensor unit 204-1 upon completion of measurement by the sensor unit 204-1. The sensor unit 204-1 may also activate autonomously, similar to the control unit 205. After completing measurement, the sensor unit 204-1 transitions to a sleep state.

[0028] In this operation, when control unit 205 receives a measurement command from host device 201, it sets delay time T in timer 206 and transitions to a sleep state as shown in Fig. 5 (at this time, sensing device 200-1 transitions to a sleep state). Also, as shown in Fig. 5, after delay time T has elapsed, control unit 205 starts up for an extremely short time, activates sensor unit 204-1, or causes sensor unit 204-1, which has autonomously activated due to the elapse of delay time T, to start measurement, and then transitions back to the sleep state. In this case, if delay time T is set so that the measurement completion time of sensor unit 204-1 is immediately before the next time control unit 205 is activated and transmits measurement data to host device 201, it becomes possible to transmit measurement data immediately after sensor unit 204-1 completes measurement from sensing device 200-1 to host device 201 in real time.

[0029] Specifically, if the time interval (hereinafter referred to as the measurement data transmission interval or measurement interval) during which sensing device 200-1 performs measurement and transmits measurement data to host device 201 is R, then delay time T can be calculated as T=RCS, and this delay time T is set in timer 206. Here, C is the measurement time specific to sensor unit 204-1, and S is slack time, which includes the time to receive a measurement command from the host device, the time to transmit measurement data, the time required for initialization when sensing device 200-1 is started up from a sleep state (startup time), the time required for other processing, the time required for processing such as timer time error, and operational slack.

[0030] For example, if the measurement interval is 1 minute, the measurement time C of sensor unit 204-1 is 10 seconds, the startup time of sensing device 200-1 is 2 seconds, and the margin time S including this startup time is 3 seconds, then the delay time T of timer 206 should be set to 60-10-3=47 seconds. If the time set in timer 206 is longer than this value, the measurement of sensor unit 204-1 will not be completed by the time the next measurement data is to be transmitted to host device 201, making it impossible to transmit the measurement data. On the other hand, if the time set in timer 206 is shorter than the above-mentioned 47 seconds, the time during which sensor unit 204-1 is activated will increase, resulting in increased power consumption. However, since the measurement of sensor unit 204-1 is completed with sufficient time to do so, operational reliability will improve. For this reason, it is desirable to adjust delay time T taking into consideration the balance between operational timing margin, power consumption, etc.

[0031] The measurement interval R can be arbitrarily set by the user for each sensor unit when installing the sensing device or before or after operation has started, taking into account the power consumption of the sensor unit 204. Alternatively, the host device 201 can arbitrarily set the measurement interval R for each sensor unit based on settings input by the user to the host device or results of calculations and analysis by the host device itself. For example, if the power consumption of sensor unit 204-1 is large, the average power consumption can be reduced by extending the measurement interval to one minute, ten minutes, etc.

[0032] Note that sensor unit 204-2 can be equipped with any sensor that is the same as or different from sensor unit 204-1. In this case, if the measurement time of sensor unit 204-2 is sufficiently short compared to the startup time of control unit 205, it can start measurement immediately after receiving a measurement command from host device 201 and transmit the measurement data to host device 201 immediately after measurement is completed. If measurement and transmission to the host device are not completed during the startup time of control unit 205, a delay time can be set taking into account the measurement time of sensor unit 204-2 and measurement can be started, as with sensor unit 204-1. If the measurement times or measurement intervals of sensor units 204-1 and 204-2 are different, it is only necessary to calculate the necessary delay times T1 and T2 for sensor units 204-1 and 204-2 and start measurement after the respective delay times have elapsed.

[0033] As described above, according to the remote sensing system and sensing device of the first embodiment, by using a timer to delay the start of measurement by the sensor unit so that measurement by the sensor unit is completed just before the time to transmit measurement data to the host device, it becomes possible to report the measurement value immediately after measurement completion to the host device in real time even when using a sensor whose measurement time is longer than the startup time of the sensing device. In this case, by setting the timer time = measurement interval - measurement time of the sensor unit - margin time, it becomes possible to complete measurement by the sensor unit just before transmission to the host device. [Example]

[0034] Fig. 6 is a diagram showing the configuration of a sensing device and a remote sensing system according to the second embodiment. The sensing device and the remote sensing system according to the second embodiment have substantially the same configuration as the sensing device and the remote sensing system according to the first embodiment shown in Fig. 4, but differs from the sensing device 200-1 according to the first embodiment in that a battery 213 connected to a power supply circuit 207 is newly provided in the sensing device 200-3 according to the second embodiment.

[0035] 6, the same components as those of the sensing device and remote sensing system shown in FIG. 4 are denoted by the same reference numerals. Also, while only the configuration of sensing device 200-3 is shown in FIG. 6, sensing device 200-4 also has a similar configuration. Additionally, the following description focuses on sensing device 200-3, explaining the operation and communication with host device 201, but the same applies to sensing device 200-4.

[0036] In the second embodiment, the host device 201 transmits a measurement command 210 to the sensing device 200-3 via the communication medium 209, and the sensing device 200-3 transmits measurement data to the host device 201 at a measurement interval R. The host device 201 transmits the measurement command 210 including information indicating the measurement interval R, and upon receiving the measurement command 210, the control unit 205 calculates a delay time T by subtracting, for example, the measurement time C and slack time S of the sensor unit 204-1 from the value of the measurement interval R indicated by the information included therein. (The measurement time C and slack time S are as described in the first embodiment.) The control unit 205 writes this delay time T into a timer setting command 212, sends (inputs) the timer setting command 212 to the timer 206 via the timer communication line 208, and sets the delay time T in the timer 206. Then, the control unit 205 activates the sensor unit 204-1 after the delay time T has elapsed, or causes the sensor unit 204-1, which has autonomously activated after the delay time T has elapsed, to start measurement.

[0037] This configuration makes it possible to freely set the measurement interval R using the host device 201. In particular, when the power consumption of the sensor unit is large, it is possible to reduce the power consumption of the power supply circuit 207 by setting the measurement interval R long under normal circumstances and shortening the measurement interval R only when necessary.

[0038] As described above, in the second embodiment, the battery 213 is further connected to the power supply circuit 207, and the sensing device 200-3 is configured to operate using the charged power of the battery 213. The battery 213 may be a disposable primary battery, or may be a secondary battery that is charged little by little using environmental power generation using a solar cell, heat, temperature, vibration, or the like, or power supplied from an external source such as a charger or optical power supply.

[0039] In this configuration, the control unit 205 reads the remaining battery capacity V214, and when transmitting measurement data from the sensing device 200-3 to the host device 201, the control unit 205 includes the value of the remaining battery capacity V214 in the transmission information 211 and notifies the host device 201. If the remaining battery capacity V214 is below a specified value, the host device 201 reduces the measurement frequency of the sensor unit that consumes a lot of power, and on the other hand, if it exceeds the specified value, it restores the measurement frequency to its original value.

[0040] In this process, the host device 201 reduces the measurement frequency of the sensor unit by lengthening the measurement interval R of the sensor unit (by sending a measurement command 210 including information indicating the set long measurement interval R), and restores or increases the measurement frequency by shortening the measurement interval R of the sensor unit (by sending a measurement command 210 including information indicating the set short measurement interval R). By taking such a process, it is possible to prevent the battery from running out, and to continue or extend the operation time of the sensing device without stopping measurement by the sensor unit.

[0041] It should be noted that the measurement interval R does not necessarily need to be included in all measurement commands 210. For example, a default value for the measurement interval R may be set in advance in the control unit 205, and if the measurement interval R is not included in the measurement command 210, the delay time T may be calculated using the default value, or the measurement interval R may be notified from the host device 201 to the sensing device 200-3 by another command, notification, command, etc. different from the measurement command 210. Alternatively, the measurement interval R may be included in the measurement command 210 or another command, etc., only when the measurement interval R is changed, and notified from the host device 201 to the sensing device 200-3.

[0042] Furthermore, in the second embodiment, the above-described configuration enables the plurality of sensor units 204-1 and 204-2 to perform measurements and transmit measurement data at different measurement intervals R. For example, the operations of sensor units 204-1 and 204-2 will be described assuming that sensor units 204-1 and 204-2 require measurement times C1 and C2, respectively, and that the measurement interval R for sensor unit 204-1 is 30 seconds and the measurement interval R for sensor unit 204-2 is 20 seconds.

[0043] 7 is a diagram showing an example of the operational states, contents, and timing of sensor units 204-1 and 204-2, sensing device 200-3, and host device 201 in the second embodiment. In this example, sensing device 200-3 intermittently activates for a short period (e.g., 1 second) at a 10-second activation cycle to perform measurement operations. Host device 201 transmits to sensing device 200-3 either measurement command #1 instructing sensor unit 204-1 to perform measurement, or measurement command #2 instructing sensor unit 204-2 to perform measurement, or both.

[0044] 8 is a diagram showing an example of a measurement command transmitted from the host device 201 to the sensing device 200-3 in the second embodiment, and an example of measurement data returned by the sensing device 200-3 to the host device 201. (a) shows an example of the case where the host device 201 simultaneously transmits measurement commands #1 and #2, (b) shows an example of the case where only measurement command #1 is transmitted, and (c) shows an example of the case where only measurement command #2 is transmitted, and each measurement command includes the measurement interval R of each sensor unit.

[0045] When sensing device 200-3 receives a measurement command, it repeats the following operations for each target sensor unit specified in the measurement command: 1) acquires measurement data from the target sensor unit and returns it to host device 201; 2) calculates delay time T from the measurement interval R for each target sensor unit in the measurement command, and the measurement time C and margin time S specific to the target sensor unit; and 3) sets delay time T in timer 206 and starts measurement at the target sensor unit after the timer set time has elapsed.

[0046] 7, for example, the control unit 205 of the sensing device 200-3 starts up at the above-mentioned start-up period, and upon receiving measurement commands #1 and #2 shown in Fig. 8(a) from the host device 201, acquires measurement data #1 and measurement data #2 from the target sensor units 204-1 and 204-2, respectively, and returns the measurement data #1 and #2 as measurement data #1 and #2 shown in Fig. 8(a') to the host device 201. The control unit 205 also calculates a delay time T1 by subtracting the measurement time C1 and margin time S of the sensor unit 204-1 from the measurement interval R (30 seconds) corresponding to the sensor unit 204-1 included in the measurement commands #1 and #2, and similarly calculates a delay time T2 by subtracting the measurement time C2 and margin time S of the sensor unit 204-2 from the measurement interval R (20 seconds) corresponding to the sensor unit 204-2 included in the measurement commands #1 and #2. The control unit 205 sets the delay times T1 and T2 calculated for each sensor unit in the timer 206 and transitions to a sleep state. Note that the sensing device 200-3 may be provided with a different timer for each sensor unit. In that case, the control unit 205 sets the delay times T1 and T2 calculated for each sensor unit in a separate timer.

[0047] On the other hand, when the upper device 201 sends measurement commands #1 and #2 shown in Figure 8(a), it receives measurement data #1 and #2 shown in Figure 8(a') from the sensing device 200-3; similarly, when it sends measurement command #1 shown in Figure 8(b), it receives measurement data #1 shown in Figure 8(b'), and when it sends measurement command #2 shown in Figure 8(c), it receives measurement data #2 shown in Figure 8(c').

[0048] In other words, the host device 201 always receives measurement data from the target sensor unit specified in the measurement command. With this type of operation, the host device 201 does not need to deal with unexpected operations such as not being able to receive measurement data from the target sensor unit specified in the measurement command, or receiving measurement data from a sensor unit not specified in the measurement command. This has the advantage of simplifying the device's program and operation, as well as making it easier to determine whether the sensing device or sensor unit has malfunctioned.

[0049] Next, a modification of the second embodiment will be described.

[0050] In the second embodiment, the host device 201 transmits the measurement command 210 including the measurement interval R, and the sensing device 200-3 that receives the measurement command 210 calculates the delay time T from the value of the measurement interval R. In contrast to this, for example, the host device 201 may store in advance the measurement time C and the margin time S of each sensor unit of each sensing device (or some sensor units of some sensing devices), and may include the measurement interval R and the delay time T calculated from the measurement interval R in the measurement command 210 and send it to the target sensing device.

[0051] In this case, the sensing device that receives the measurement command 210 sets the delay time T included in the measurement command 210 in a timer. Note that the upper device 201 may include either the measurement interval R or the delay time T, rather than both, in the measurement command 210 and transmit it, or may transmit the measurement interval R and the delay time T separately at different timings. In this case, it is not necessary to include them in the measurement command 210, and the measurement interval R or the delay time T may be transmitted by a command other than the measurement command 210.

[0052] Furthermore, in the second embodiment, the host device 201 receives notification of the remaining battery capacity V214 from the sensing device 200-3, and if the value of the remaining battery capacity V214 is below a specified value, it reduces the measurement frequency of the sensor unit that consumes a lot of power, while if the value exceeds the specified value, it restores the measurement frequency to its original value. In contrast to this, for example, the host device 201 may change (reduce, increase, restore, etc.) the measurement frequency of the sensor unit of any sensing device based on the value of the measurement data received from that sensing device.

[0053] Specifically, for example, when the measurement target is the flow rate of a fluid in a pipeline, the host device 201 changes the measurement frequency of the sensor unit of the sensing device in accordance with changes in the flow rate measured by the sensor unit. Note that the host device 201 may also change the measurement frequency of the sensor unit of one of the sensing devices based on the value of measurement data received from the other sensing device.

[0054] Alternatively, for example, the higher-level device 201 may acquire various information (e.g., information about the weather or environment, or other information) from the outside (e.g., via equipment, devices, systems, or networks other than the sensing device), and based on that (or any) information, change the measurement frequency of the sensor unit of any sensing device (e.g., a sensing device related to the information in question).

[0055] Specifically, for example, the host device 201 acquires information such as weather and precipitation from outside and changes the measurement frequency of the sensor unit of the sensing device that measures the flow rate of fluid in the pipeline. Note that the host device 201 may comprehensively analyze the information from outside and the measurement data from the sensing device, and change the measurement frequency of the sensor unit of any of the sensing devices based on the analysis results. Additionally, the host device 201 may change the measurement frequency of the sensor unit of any or all of the sensing devices based on setting values ​​input to the host device 201 by the user.

[0056] As described above, according to the remote sensing system and sensing device of the second embodiment, by notifying the sensing device of the measurement data transmission interval or measurement interval from the host device, it is possible to synchronize the timing of data acquisition by the host device and measurement by the sensing device, and also to arbitrarily set the data transmission time or measurement interval of the sensing device from the host device.

[0057] Furthermore, by having the sensing device read out the remaining battery capacity as appropriate and transmit (notify) the read-out value of the remaining battery capacity to the host device, the host device can take measures such as reducing the measurement frequency of the sensor unit of the sensing device or restoring the reduced measurement frequency according to the remaining battery capacity. By taking such measures, it becomes possible to reduce the power consumption of the sensing device and prevent battery depletion, and to continue or extend the operation time of the sensing device without stopping measurement by the sensor unit.

[0058] Furthermore, because the timing of receiving a measurement command from the host device and completing measurement coincides for each sensor, the sensing device can transmit the measurement data of the sensor specified in the measurement command immediately after receiving the measurement command. This configuration provides a 1:1 relationship between measurement commands and responses to the sensor, which simplifies communication management, eliminates the need to wait for a response of measurement data from the sensor, and has the advantage of making it easier to identify missing measurement data or malfunctions in the sensing device or sensor. [Example]

[0059] Fig. 9 is a diagram showing the configuration of a sensing device and a remote sensing system according to the third embodiment. The sensing device and remote sensing system according to the third embodiment have similar configurations to the sensing device and remote sensing system according to the second embodiment shown in Fig. 6. However, sensing device 200-5 according to the third embodiment differs from sensing device 200-3 according to the second embodiment in that sensor control unit 220 and timer 221 are provided in addition to sensor 222 inside sensor unit 204-3, and timer 206 has been eliminated.

[0060] 9, the same components as those of the sensing device and remote sensing system shown in FIGS. 4 and 6 are denoted by the same reference numerals. Although only the configuration of sensing device 200-5 is shown in FIG. 9, sensing device 200-6 also has a similar configuration. In addition, the following description focuses on sensing device 200-5, explaining the operation and communication with host device 201, but the same applies to sensing device 200-6.

[0061] As described above, in the third embodiment, the sensor unit 204-3 is equipped with the sensor 222, the sensor control unit 220, and the timer 221, and is configured so that the sensor unit 204-3 alone can autonomously perform operations such as activation by the timer 221 and measurement. Note that the sensor control unit 220 controls the measurement operation of the sensor 222, similar to the control unit 205 in the first embodiment. Also, similar to the timer 206 in the first embodiment, the timer 221 can be configured so that the sensor control unit 220 can set the timer time and notify the sensor control unit 220 that the set time has elapsed.

[0062] 10 is a diagram showing an example of the operational states, contents, and timing of the sensor unit 204-3, the sensing device 200-5, and the host device 201 in the third embodiment. In this example, when the control unit 205 of the sensing device 200-5 is started, it receives a measurement command 210 from the host device 201 via the communication medium 209, instructing the sensor unit 204-3 to perform measurement. The control unit 205 calculates a delay time T by subtracting the measurement time C and margin time S of the sensor unit 204-3 from the measurement interval R included in the measurement command 210, and transmits a sensor unit measurement command 215 including this delay time T to the sensor control unit 220 via the sensor communication line 202-1. The control unit 205 also acquires measurement data of the sensor 222 from the sensor unit 204-3 via the sensor control unit 220 and returns the measurement data to the host device 201.

[0063] When sensor control unit 220 receives sensor unit measurement command 215, it sets delay time T included in the command in timer 221 and transitions to a sleep state. Sensor control unit 220 wakes up after delay time T has elapsed to activate sensor 222, or causes sensor 222 that has autonomously activated after delay time T has elapsed to start measurement. After this, host device 201, sensing device 200-5, and sensor unit 204-3 all repeat the same operation. This operation enables sensing device 200-5 to return measurement data to host device 201 immediately before measurement interval R has elapsed since receiving the measurement command from host device 201.

[0064] By enabling the sensor unit to start measurement autonomously after the delay time T has elapsed, it is possible to reduce the number of times and startup time of sensing device 200-5, thereby saving power consumption, and also to simplify the operation of sensing device 200-5, particularly control unit 205. The simplification of operation is particularly noticeable when multiple sensor units 204-3, 204-4 with different measurement times and measurement cycles are installed, and control unit 205 does not need to perform complex processing such as starting measurement by each sensor unit using multiple timers that differ for each installed sensor unit.

[0065] As described above, according to the remote sensing system and sensing device of the third embodiment, the sensor unit is equipped with a timer, a sensor, and a sensor control unit, so that the sensor unit can autonomously start up and perform measurements after the timer setting time has elapsed. This configuration makes it possible to reduce the number of times the sensing device is started up and the startup time, which is advantageous in terms of reducing the power consumption of the sensing device and simplifying its operation. [Example]

[0066] Figure 11 is a diagram showing the configuration of a sensing device and remote sensing system according to the fourth embodiment. The sensing device and remote sensing system according to the fourth embodiment have substantially the same configuration as the sensing device and remote sensing system according to the third embodiment shown in Figure 9, with a sensor, sensor control unit, and timer mounted within the sensor unit, and configured so that the sensor unit alone can autonomously perform operations such as timer activation and measurement. Note that in Figure 11, the same components as those in the sensing device and remote sensing systems shown in Figures 4, 6, and 9 are designated by the same reference numerals.

[0067] 12 is a diagram showing an example of the operational states, contents, and timing of the sensor units 204-5 and 204-7, the sensing devices 200-7 and 200-8, and the host device 201 in the fourth embodiment. In this example, time slots #1 and #2 are assigned to the sensing devices 200-7 and 200-8, respectively, and each sensing device activates only during the assigned time slot and communicates exclusively with the host device 201.

[0068] In this example, one cycle consists of three time slots #1 to #3, and both sensor unit 204-5 of sensing device 200-7 and sensor unit 204-7 of sensing device 200-8 perform measurements at intervals of one time slot cycle.

[0069] In time slot #1, host device 201 transmits, for example, a measurement command 210 for sensor unit 204-5 to sensing device 200-7, notifying one time slot cycle (the interval between time slots #1 to #3) as the measurement interval R. When control unit 205-1 of sensing device 200-7 receives measurement command 210, it subtracts measurement time C3 and margin time S of sensor unit 204-5 from the notified measurement interval to calculate delay time T3, and transmits sensor unit measurement command 215 to sensor unit 204-5 via sensor communication line 202-1 to notify delay time T3. In addition, control unit 205-1 acquires measurement data of sensor 222 from sensor unit 204-5 via sensor control unit 220 and returns the measurement data to host device 201.

[0070] When sensor control unit 220 of sensor unit 204-5 receives sensor unit measurement command 215, it sets delay time T3 in timer 221. After delay time T3 has elapsed, sensor control unit 220 autonomously starts up sensor 222, or causes sensor 222 that has autonomously started up after delay time T has elapsed to start measurement. Sensor 222 completes measurement in time slot #1 of the next period. After this, host device 201, sensing device 200-7, and sensor unit 204-5 all repeat the same operations.

[0071] Similarly, in time slot #2, host device 201 transmits to sensing device 200-8, for example, a measurement command 210 for sensor unit 204-7, notifying one time slot period (the interval between time slots #1 to #3) as the measurement interval R. When control unit 205-2 of sensing device 200-8 receives measurement command 210, it subtracts measurement time C4 and margin time S of sensor unit 204-7 from the notified measurement interval to calculate delay time T4, and transmits sensor unit measurement command 215 to sensor unit 204-7 via sensor communication line 202-2 to notify delay time T4. Control unit 205-2 also acquires measurement data of sensor 222 from sensor unit 204-7 via sensor control unit 220 and transmits the measurement data to host device 201.

[0072] When sensor control unit 220 of sensor unit 204-7 receives sensor unit measurement command 215, it sets delay time T4 in timer 221. After delay time T4 has elapsed, sensor control unit 220 autonomously starts up sensor 222, or causes sensor 222 that has autonomously started up after delay time T has elapsed to start measurement. Sensor 222 completes measurement in time slot #2 of the next period. After this, host device 201, sensing device 200-8, and sensor unit 204-7 all repeat the same operations.

[0073] In this way, different time slots are assigned to a plurality of sensing devices, and each sensing device operates only within the assigned time slot, so that the sensing devices do not interfere with each other's communications or operations.

[0074] In this example, one cycle consists of three time slots, #1 to #3, and two sensing devices are used, but these can be freely increased or decreased depending on the system scale. Also, the measurement interval for each sensor unit is one time slot cycle, but the measurement interval can be set to any integer multiple of one time slot cycle. When time slots are used as in this example, the number of time slots or the number of time slot cycles can be used instead of time as the measurement interval R or delay time T in the sensing device or sensor unit. Also, in each sensing device, multiple sensor units can perform measurements at independent cycles.

[0075] As described above, according to the remote sensing system and sensing device of the fourth embodiment, it is possible to realize a remote sensing system that avoids communication collisions by periodically assigning time slots to each of multiple sensing devices connected to a higher-level device, and configuring each sensing device to occupy the assigned time slot and communicate with the higher-level device.

[0076] Although the above describes various embodiments and variations of the present invention, the present invention is not limited to the above-described exemplary embodiments and includes various variations. For example, the above-described exemplary embodiments have been described in detail to facilitate understanding of the present invention, and the present invention is not limited to those including all of the components described herein. Furthermore, it is possible to replace part of the components of one exemplary embodiment with the components of another exemplary embodiment. It is also possible to add the components of another exemplary embodiment to the components of one exemplary embodiment. Furthermore, it is also possible to add, delete, or replace part of the components of each exemplary embodiment with other components. Furthermore, some or all of the above-described components, functions, processing units, processing means, etc. may be implemented in hardware, for example, by designing them as integrated circuits. Furthermore, the control lines and information lines in the figures are only those considered necessary for explanation, and are not necessarily all shown. It is also possible to consider that almost all components are interconnected. [Explanation of symbols]

[0077] 100: Sensing device 101: Upper device 102: Sensor unit 103: Communications Department 104: Control unit 200: Sensing device 201: Upper device 202: Sensor communication line 203: Power line 204: Sensor unit 205: control unit, 206: Timer 207: Power supply circuit 208: Timer communication line 209: Communication media 210: Measurement command 211: Transmission information 212: Timer setting command 213: Battery 214: Battery remaining 215: Sensor unit measurement command 220: Sensor control unit 221: Timer 222: Sensor

Claims

1. at least one sensor unit that measures the measurement object for a fixed measurement time; a power supply line for supplying power to the sensor unit; a control unit that is activated intermittently and transmits measurement data to an external device, the control unit instructing the sensor unit to start measurement and acquiring the measurement data from the sensor unit after the measurement is completed; a timer that is set by the control unit and notifies the control unit of the passage of the time, the control unit sets a time until activation of the sensor unit in the timer so that the measurement time of the sensor unit is completed before the transmission of the measurement data. Sensing device.

2. The sensing device according to claim 1, the control unit transmits the measurement data at a predetermined measurement interval; the set time is the time from the start of the measurement interval to the activation of the sensor unit; Sensing device.

3. The sensing device according to claim 1, the control unit transmits the measurement data at a predetermined measurement interval, and sets a time obtained by subtracting the measurement time and a margin time from the measurement interval as the set time on the timer. Sensing device.

4. The sensing device according to claim 3, The margin time includes at least a transmission time of the measurement data and a startup time of the sensing device. Sensing device.

5. The sensing device according to claim 3, the control unit receives a measurement command including information indicating the measurement interval from the external device, and transmits the measurement data to the external device at the measurement interval indicated by the information. Sensing device.

6. The sensing device according to claim 3, a battery for supplying power to the control unit, the sensor unit, and the timer; the control unit reads a remaining battery capacity from the battery, transmits the remaining battery capacity to the external device, receives a measurement command from the external device including information indicating the measurement interval corresponding to the remaining battery capacity, and transmits the measurement data to the external device at the measurement interval indicated by the information. Sensing device.

7. 3. The sensing device according to claim 2, At least one of the sensor units includes the timer and a sensor control unit, the sensor control unit sets the set time in the timer, When the timer notifies the sensor control unit that the set time has elapsed, the sensor control unit causes the sensor unit to start the measurement. Sensing device.

8. The sensing device according to claim 3 or claim 7, A time slot is assigned to the sensing device in advance, The sensing device is activated only during the time slot and transmits the measurement data to the external device; The measurement interval is an interval that is an integer multiple of one period of the time slot. Sensing device.

9. A sensing system comprising a host device and one or more sensing devices connected to the host device, The sensing device is at least one sensor unit that measures the measurement object for a fixed measurement time; a power supply line for supplying power to the sensor unit; a control unit that is activated intermittently and transmits measurement data to the host device, the control unit instructing the sensor unit to start measurement and acquiring the measurement data from the sensor unit after the measurement is completed; a timer that is set by the control unit and notifies the control unit of the passage of the time, The control unit sets a time until activation of the sensor unit in the timer so that the measurement time of the sensor unit is completed before the measurement data is transmitted. Sensing system.

10. 10. The sensing system of claim 9, the control unit transmits the measurement data at a predetermined measurement interval; the set time is the time from the start of the measurement interval to the activation of the sensor unit; Sensing system.

11. 11. The sensing system of claim 10, the host device transmits a measurement command including information indicating the measurement interval to the sensing device; the control unit receives the measurement command and transmits the measurement data to the higher-level device at the measurement interval indicated by the information included in the measurement command. Sensing system.

12. 12. The sensing system of claim 11, a battery for supplying power to the control unit, the sensor unit, and the timer; the control unit reads out a remaining battery capacity from the battery and transmits the remaining battery capacity to the host device; the upper device receives the remaining battery charge, sets the measurement interval according to the remaining battery charge, and transmits the measurement command including information indicating the set measurement interval to the sensing device; Sensing system.

13. 11. The sensing system of claim 10, the host device periodically assigns time slots at predetermined intervals to each of the sensing devices; Each of the sensing devices operates only within the assigned time slot and transmits the measurement data to the host device; The measurement interval is an interval that is an integer multiple of one period of the time slot. Sensing system.

14. A sensing method using a sensing device including at least one sensor unit that measures a measurement target for a certain measurement time, and a control unit that is activated intermittently, supplies power to the sensor unit, acquires measurement data by the sensor unit, and outputs the measurement data, a time until activation of the sensor unit is set so that the measurement time is completed before the output of the measurement data; Sensing method.

15. 15. The sensing method of claim 14, outputting the measurement data at predetermined measurement intervals; The set time is the time from the start of the measurement interval to the start of the measurement. Sensing method.

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