JP5722720B2 - Sensor node, device monitoring system, and low battery level notification method - Google Patents

Description

  The present invention relates to a device monitoring technique using a sensor node.

  As a monitoring system for monitoring the operating state of each device in a factory, a system using a sensor node as a wireless terminal equipped with a sensor is known (for example, Patent Documents 1 and 2 below). In such a monitoring system, for example, a sensor node including a vibration sensor is attached to a rotating system device. The sensor node transmits data measured by the vibration sensor to the monitoring device by wireless communication. The monitor can monitor whether there is an abnormality in the rotating device based on the measurement data transmitted to the monitoring device.

  In such a monitoring system, when the measurement data indicates an abnormality of the device, the monitor moves to the installation location of the device and checks the operating state of the device in which the abnormality has occurred, and makes adjustments and repairs as necessary. It will be. However, if the supervisor does not accurately grasp the equipment layout in the factory, the supervisor may have a hard time specifying the location of the equipment to be inspected. In a factory, many devices of the same type may be installed. For example, in a sewage treatment plant, water treatment facilities may be composed of a plurality of lines, and many pumps of the same model and the same capacity may be arranged side by side. Or, in order to improve the convenience of management of devices, similar devices may be arranged in a concentrated manner. In such a situation, it has not always been easy for the monitor to specify which device is to be inspected.

  In addition, a battery may be used as a power source for the sensor node (for example, Patent Document 1 below). In such a sensor node, it is necessary to replace the battery when the battery runs out and the remaining battery level is low. Battery exhaustion can be grasped when the sensor node stops sending measurement data to the monitoring device. However, if the battery is replaced after that, even if an abnormality occurs in the device between the time when the battery runs out and the time when the battery is replaced, the monitoring apparatus cannot grasp the abnormality. For this reason, there is a possibility that proper device monitoring cannot be performed. Moreover, even if the supervisor notices that the battery has run out and tries to replace the battery at the place where the device is installed, it may be difficult to identify the device for which the battery should be replaced, as in the case of the device in which the abnormality has occurred.

JP 2010-49584 A JP 2008-232934 A

  Based on at least a part of the problems described above, the problem to be solved by the present invention is to improve the convenience of a monitoring system using sensor nodes.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
The first aspect of the present invention is a sensor node of a plurality of sensor nodes for monitoring a device,
A sensor for measuring a physical quantity that reflects the operating state of the device;
A storage unit for storing information based on a measurement result of the sensor;
A wireless communication unit that transmits information based on the measurement result of the sensor to the monitoring device by wireless communication at a predetermined timing; and
A battery accommodating portion for accommodating a battery as a power source of the sensor node;
A voltage detector for detecting a voltage value of the battery;
A light-emitting unit that continuously emits light and notifies the position of the sensor node when the detected voltage value falls below a predetermined value;
With
The wireless communication unit, when the detected voltage value becomes a predetermined value or less, regardless of the predetermined timing, the voltage value or information indicating that the voltage value has become the predetermined value or less And information based on the measurement result not transmitted to the monitoring device stored in the storage unit is transmitted to the monitoring device, and subsequent wireless communication is stopped.
It is a sensor node.

Application Example 1 A sensor node for monitoring a device,
A sensor for measuring a physical quantity that reflects the operating state of the device;
A wireless communication unit that transmits information based on the measurement result of the sensor to the monitoring device by wireless communication;
A battery accommodating portion for accommodating a battery as a power source of the sensor node;
A voltage detector for detecting a voltage value of the battery;
A sensor node comprising: a light emitting unit that continuously emits light and notifies the position of the sensor node when the detected voltage value is equal to or less than a predetermined value.

  According to the sensor node having such a configuration, when the voltage value drops below a predetermined value, the light emitting unit continuously emits light, so that the monitor who looks around the installation site of the device has little remaining battery power. You can notice that. Therefore, the monitor can replace the battery before the remaining battery runs out. For this reason, it can suppress that the transmission of the information based on the measurement result from a sensor node to a monitoring apparatus resulting from the battery remaining runs out is missing. As a result, it is possible to suitably monitor the device and improve convenience. Note that continuous light emission includes intermittent light emission.

[Application Example 2] The sensor node according to Application Example 1, further including a control unit that controls an operation of the sensor node, wherein the control unit applies the sensor to the sensor at a predetermined time or at a predetermined cycle. After the power is supplied and the measurement by the sensor is performed, the first control to stop the supply of the power to the sensor, the power is supplied to the wireless communication unit, and the measurement by the sensor is performed. After the measurement, after the information is transmitted based on the measurement result by the wireless communication unit, at least one of the second control for stopping the supply of power to the wireless communication unit is performed. The sensor node to perform.

  According to the sensor node having such a configuration, power is not supplied to a part corresponding to an unnecessary process during a time when measurement or transmission of information based on the measurement result is not required. Can prolong life. As a result, maintenance costs can be reduced, and the frequency of battery replacement can be reduced, thereby improving convenience.

Application Example 3 When the detected voltage value is equal to or lower than a predetermined value, the wireless communication unit monitors the voltage value or information indicating that the voltage value is equal to or lower than the predetermined value. The sensor node according to the application example 1 or the application example 2, which is transmitted to the device.

  According to the sensor node having such a configuration, the monitoring device can immediately recognize that the remaining amount of the battery is small. Therefore, if the monitor moves to the installation site of the equipment and quickly replaces the battery, the information from the sensor node to the monitoring device is transmitted based on the measurement result due to the remaining battery level being exhausted. It can be surely prevented from missing. As a result, the device can be reliably monitored, and convenience is improved. In addition, when the monitoring device recognizes that the remaining battery level is low and the monitor moves to the equipment installation site, even if the same type or similar equipment is centrally arranged, the light emitting unit With this light emission, it is possible to easily grasp the remaining battery level of the sensor node attached to which device, and convenience is improved.

[Application Example 4] The sensor node according to any one of Application Examples 1 to 3, wherein the storage unit stores information based on the measurement result of the sensor, and the information based on the measurement result by the wireless communication unit. A transmission timing control unit that controls the transmission timing of the first measurement, and the transmission timing control unit, after the first measurement by the sensor, transmits information based on the measurement result of the first measurement to the monitoring device. The first measurement is not transmitted, and after the second measurement performed after the first measurement, information based on the first measurement and the measurement result of the second measurement is collectively transmitted to the monitoring device. Sensor node that can be controlled in mode.

  According to the sensor node having such a configuration, information based on the measurement result can be collectively transmitted to the monitoring device for a predetermined number of times, and therefore, compared to the configuration in which information based on the measurement result is transmitted to the monitoring device every time measurement is performed. The power consumption of the sensor node can be suppressed, and the battery life can be extended. The first measurement may be a plurality of measurements.

Application Example 5 In the sensor node according to Application Example 4, the sensor node includes an abnormality determination unit that determines an abnormality of the device based on a measurement result of the sensor, and the transmission timing control unit is configured so that the device is abnormal. When the device is determined to be abnormal, and the device is determined to be abnormal, information based on the measurement result corresponding to the device abnormality determination is stored in the storage unit. A sensor node capable of control in the second mode for transmitting to the monitoring device together with information based on the measurement result not transmitted to the monitoring device.

  According to the sensor node having such a configuration, it is possible to immediately grasp the abnormality of the device on the monitoring device side. Therefore, the monitoring staff can quickly check the equipment, and can prevent the malfunction of the equipment from causing a malfunction of the equipment or an accident.

[Application Example 6] The sensor node according to any one of Application Example 1 to Application Example 3, wherein the storage unit stores information based on the measurement result of the sensor, and the measurement node An abnormality determination unit that determines an abnormality of the device, and the wireless communication unit transmits information based on the measurement result to the monitoring device only when the device is determined to be abnormal, and transmits the information. The information based on the measurement result is a sensor node including information based on the measurement result corresponding to the determination that the abnormality is present and information based on the measurement result stored in the storage unit.

  According to the sensor node having such a configuration, it is possible to further extend the life of the battery by further reducing the number of times of transmission of information based on the measurement result as compared with the configurations of the application examples 4 and 5.

Application Example 7 In the sensor node according to Application Example 5 or Application Example 6, the abnormality determination unit includes information based on the measurement result acquired by a new measurement and a predetermined number of times stored in the storage unit. A sensor node that determines abnormality of the device based on a degree of deviation from a moving average value of information based on the measurement result.

  According to the sensor node having such a configuration, even if the characteristics of the physical quantity of the device change over time due to factors other than the abnormality of the device, it is possible to accurately determine the abnormality.

Application Example 8 A sensor node for monitoring a device that measures a physical quantity that reflects the operation state of the device and transmits information based on a measurement result of the sensor to a monitoring device by wireless communication A wireless communication unit, an abnormality determination unit for determining abnormality of the device based on a measurement result of the sensor, and when the device is determined to be abnormal, the sensor continuously emits light and the sensor A sensor node comprising a light emitting unit for informing the position of the node.

  According to the sensor node having such a configuration, a monitoring person who looks around the installation site of the device can easily notice that an abnormality has occurred in the device. Therefore, the monitor can quickly deal with the abnormality of the device and can suppress the occurrence of an accident or the like. In addition, based on the information based on the measurement results sent to the monitoring device, the monitoring device grasps the abnormality of the device, and when the monitor moves to the installation site of the device, the same or similar devices are aggregated. Even if they are arranged, it is possible to easily grasp which device is abnormal due to the light emission of the light emitting unit, and the convenience is improved.

Application Example 9 The sensor according to Application Example 8, wherein the light emitting unit stops the light emission when a predetermined time elapses or based on an instruction from the monitoring device when the light is continuously emitted. node.

  According to the sensor node having such a configuration, since the light emitting unit does not continuously emit light after the inspection of the device by the supervisor is completed, it is possible to suppress confusion with the device in which an abnormality has occurred and the inspection has not been completed. . In addition, the battery life can be extended. In addition, since it is not necessary to provide the sensor node with an input means for inputting an instruction to stop the light emission to the sensor node, the configuration of the sensor node can be simplified. Note that the configurations of the application examples 2 and 4 to 7 can be added to the configurations of the application examples 8 and 9.

  In addition to the sensor node described above, the present invention can also be realized as a device monitoring system including a sensor node and a monitoring device, a battery remaining amount low notification method, an abnormality notification method, and the like.

It is explanatory drawing which shows schematic structure of the equipment monitoring system 20 as an Example of the equipment monitoring system of this invention. 3 is an explanatory diagram showing a schematic configuration of a sensor node SNx that constitutes the device monitoring system 20. FIG. It is a flowchart which shows the flow of the measured value transmission process in sensor node SNx.

A. Example:
A schematic configuration of a device monitoring system 20 as an embodiment of the device monitoring system of the present invention is shown in FIG. The device monitoring system 20 is a system that monitors the operating state of each device arranged in a factory via wireless communication. In the present embodiment, a description will be given on the assumption that the operating states of a plurality of pumps P1 to P12 as rotating system devices are monitored. As illustrated in FIG. 1, the device monitoring system 20 includes sensor nodes SN1 to SN12, gateways (routers) GW1 and GW2, and a server SV. In the following description, the sensor nodes SN1 to SN12 are collectively referred to as a sensor node SNx. The pumps P1 to P12 are also collectively referred to as a pump Px.

  The sensor node SNx includes a sensor and a wireless communication module. One sensor node SNx is attached to each casing of the pump Px to be monitored. In the present embodiment, the sensor node SNx is attached to the pump Px by a magnet.

  The gateways GW1 and SW2 include a wireless communication module and a wired LAN interface. The gateways GW1 and GW2 are connected to the local area network LAN via a wired LAN interface. The gateways GW1 and GW2 perform wireless communication with the sensor node SNx. In this embodiment, the wireless communication is performed in accordance with the wireless standard IEEE 802.15.4.

  The server SV is a monitoring device that monitors the operating state of the pump Px. The server SV receives information based on measurement data measured by the sensor of the sensor node SNx from the sensor node SNx via the gateways GW1 and GW2 and the local area network LAN. The received data is displayed on a display and recorded on a storage medium. The monitor performs abnormality monitoring of the pump Px based on the received data. The abnormality includes not only a state in which the pump Px has failed (a state in which at least a part of functions are disabled) but also a state that is a precursor to failure. The supervisor can also analyze the data accumulated in the server SV and use it for the maintenance management of the pump Px, such as the life prediction of the pump Px and the formulation of the maintenance management plan. In addition, what is necessary is just to set suitably the connection form of gateway GW1, GW2 and server SV. For example, the gateways GW1 and GW2 may be connected to the server SV via a WAN (Wide Area Network) such as the Internet.

  A schematic configuration of the sensor node SNx is shown in FIG. As illustrated, the sensor node SNx includes a CPU 110, a battery box 120, a power supply circuit 130, a vibration sensor 140, a sampling circuit 150, a wireless communication module 160, a memory 170, an LED (Light Emitting Diode) 180, and an RTC (Real Time Clock). 190 is provided.

  In addition to controlling the overall operation of the sensor node SNx, the CPU 110 also operates as a control unit 111, a transmission timing control unit 112, and an abnormality determination unit 113. Details of these functional units will be described later. The battery box 120 accommodates a battery as a power source for the sensor node SNx. The power supply circuit 130 transforms the battery voltage of the battery accommodated in the battery box 120 to a predetermined voltage value, and supplies it to each part of the sensor node SNx.

  The vibration sensor 140 detects vibration generated by driving the pump Px. In the present embodiment, a triaxial type acceleration sensor is used as the vibration sensor 140. In the present embodiment, the acceleration in only one axial direction (the radial direction of the rotating shaft) is detected, so that the single-axis type may be used. Various types of known acceleration sensors can be used. The sampling circuit 150 is connected to the vibration sensor 140. The vibration sensor 140 includes an amplification circuit that amplifies the output value of the vibration sensor 140, a sampling circuit that samples the amplified output value at a predetermined frequency, and an A / D circuit that A / D converts the sampling value. The sampling circuit 150 outputs the output value of the vibration sensor 140 subjected to A / D conversion to the CPU 110 as an acceleration value A.

  In this embodiment, the sampling circuit 150 is also connected to the battery box 120. That is, the vibration sensor 140 also serves as a voltage detection circuit that detects the voltage value of the battery. The sampling circuit 150 outputs the A / D converted battery voltage as a voltage value V to the CPU 110.

  The wireless communication module 160 is a control circuit for performing wireless communication, and includes hardware such as a modulator, an amplifier, and an antenna. The memory 170 is a rewritable nonvolatile storage medium. The LED 180 emits light when the CPU 110 detects a decrease in the voltage value V or when an abnormality of the pump Px is detected, and notifies the installation position of the own device. Note that various light emitting means such as a light bulb may be employed instead of the LED 180.

  The RTC 190 functions as a clock module that measures the current time (here, year, month, day, hour, minute, second). In the embodiment, a battery housed in the battery box 120 is used as a power source for the RTC 190. However, the RTC 190 may incorporate a dedicated battery. The RTC 190 always operates by receiving power supply from the battery regardless of whether the power switch (not shown) of the sensor node SNx is turned on or off.

  On the other hand, the supply of power to each part of the sensor node SNx excluding the RTC 190 and the CPU 110 is normally stopped even when the power switch is ON. This normal operation state is also referred to as a pause mode in the present application. In the sleep mode of the present embodiment, the CPU 110 is in a stopped state except for accepting a clock and a command. In this way, the power consumption of the CPU 110 can be reduced. However, the operation state of the CPU 110 in the sleep mode may be set as appropriate as long as a predetermined signal described later can be received. For example, all the functions of the CPU 110 may be valid. Or you may clock down with respect to a rated clock. In the register of the RTC 190, a measurement time that is a time at which measurement using the vibration sensor 140 should be started is registered in advance. Such measurement time is registered based on an instruction received by the CPU 110 from the server SV via wireless communication when the sensor node SNx is initially used. The RTC 190 outputs a predetermined signal indicating the occurrence of the timer event to the CPU 110 at the measurement time. When a predetermined signal is output to the CPU 110 in the sleep mode, the CPU 110 enables all the functions of itself and supplies power to each part of the sensor node SNx where the power supply has been stopped as a process of the control unit 111. Supply. Note that the RTC 190 may output a predetermined signal at a predetermined cycle instead of the timing of the registered time. However, if the configuration is based on the timing of the registered time, it is possible to cope with a factory operation mode, for example, intermittent operation of the pump Px, long-term suspension for inspection, and the like.

  A flow of the measurement value transmission process in the sensor node SNx is shown in FIG. The measurement value transmission process is a process of transmitting information based on the measurement result measured by the sensor node SNx using the vibration sensor 140 to the server SV at a predetermined timing. The measurement transmission process is repeatedly executed each time a predetermined signal is received from the RTC 190. When the sensor node SNx is in the dormant mode, the measurement transmission process is started after power supply to each part of the sensor node SNx is started.

  When the measurement value transmission process is started, the CPU 110 measures the acceleration value A and the voltage value V using the sampling circuit 150 (step S210). When the measurement value is acquired, the CPU 110 calculates an effective value RMS (Root Mean Square) of the vibration speed in the low frequency region (1 kHz or less) based on the acquired acceleration value A by integral calculation (step S220).

When the effective value RMS is calculated, the CPU 110 records the calculated effective value RMS in the memory 170 (step S230). When the effective value RMS is recorded, step S210 determines whether or not the following equation (1) or the following equation (2) is satisfied (step S240). Expressions (1) and (2) are OR conditions. In the expressions (1) and (2), RMS is the effective value RMS calculated most recently in step S220. MA is a moving average value described below. TH1 and TH2 are predetermined threshold values and are recorded in the memory 170.
RMS / MA ≧ TH1 (1)
V ≦ TH2 (2)

  Judgment about Formula (1) determines abnormality of pump Px with which sensor node SNx was attached, and CPU110 performs as a process of the abnormality determination part 113. FIG. Specifically, the CPU 110 first calculates the moving average value MA of the effective value RMS obtained by the latest predetermined number of times, for example, 10 measurements. The RMS value for the past measurement is recorded in the memory 170 by the above step S230 every time the measurement value transmission process is repeatedly executed. In this embodiment, the simple moving average is adopted as the moving average, but a weighted moving average may be adopted. Then, CPU 110 compares the value of RMS / MA with threshold value TH1.

  If an abnormality (including a precursor) occurs in the pump Px, the effective value RMS increases rapidly. Therefore, it can be determined that the pump Px is abnormal because RMS / MA is equal to or greater than the threshold value TH1. This determination is not limited to the expression (1), but may be performed based on the degree of deviation between the RMS value and the MA value. For example, the abnormality determination may be performed based on a difference value between the RMS value and the MA value. However, since the magnitude of the effective value RMS varies depending on the size of the electric motor, the threshold value TH1 needs to be set according to the electric capacity of the pump Px when based on the difference value. Based on the ratio as in equation (1), it is possible to set the threshold value TH1 with a uniform value regardless of the motor capability, and the configuration of the sensor node SNx can be simplified.

  As described above, if the abnormality determination is performed based on the moving average value, the characteristic of the effective value RMS has changed due to factors unrelated to the abnormality with the passage of the long-term operation time of the pump Px. However, the abnormality determination can be performed with high accuracy.

  Judgment about Formula (2) judges the voltage fall accompanying the remaining amount of a battery remaining little. That is, when Expression (2) is satisfied, it can be determined that the remaining battery level is low.

  As a result of the determination, if neither of the expressions (1) and (2) is satisfied (step S240: NO), the CPU 110 further transmits the measurement data to the server SV last time as a process of the transmission timing control unit 112. It is determined whether or not the number of measurements after performing has reached a predetermined number (step S250). This predetermined number of times is recorded in the memory 170 in advance.

  As a result of the determination, if the predetermined number of times has been reached (step S250: YES), the CPU 110 collectively transmits the effective value RMS and the voltage value V for the predetermined number of times to the server SV (step S260). The transmission of the voltage value V can be omitted. Further, the measurement value to be transmitted may be information based on the measurement result, and may be an index value obtained by calculating the measurement data, or may be the measurement data itself. Of course, both of these may be used. Then, the CPU 110 shifts the operation state of the sensor node SNx to the sleep mode as a process of the control unit 111 (step S270). On the other hand, if the predetermined number of times has not been reached (step S250: NO), CPU 110 advances the process to step S270 without transmitting measurement data. If it does in this way, the power consumption which concerns on communication can be suppressed and consumption of a battery can be suppressed.

  On the other hand, as a result of the determination, if either of the expressions (1) and (2) is satisfied (step S240: YES), the CPU 110 transmits the latest effective value RMS and voltage value V stored in the memory 170 as untransmitted. Are transmitted together with the effective value RMS to the server SV (step S280). With this configuration, it is possible to quickly grasp on the server SV side that either of the expressions (1) and (2) is satisfied. Moreover, since the past effective value RMS is also transmitted, the supervisor can also analyze the operation state of the pump Px. Note that when the expression (2) is not satisfied, the transmission of the voltage value V can be omitted. In addition, when Expression (2) is satisfied, information indicating that Expression (2) is satisfied may be transmitted instead of the voltage value V.

  The server SV may be provided with a warning function that warns the monitoring staff that either of the expressions (1) and (2) is satisfied when the transmission of the step S280 is received. For example, such a warning function may display a warning message on the display of the server SV. Alternatively, an e-mail including a warning message may be transmitted to a monitor's mobile phone or the like. Further, the MAC address of the wireless communication module 160 of the sensor node SNx, the identification information previously assigned to the sensor node SNx, the name of the pump Px, and the like are stored in the server SV in association with each other. If the warning message includes the name or the like of the pump Px that satisfies any one of (2), the monitor can easily grasp which pump Px or sensor node SNx should be dealt with.

  When the transmission is performed, the CPU 110 blinks the LED 180 to notify the installation location of the sensor node SNx (step S290). In the present embodiment, when the expression (2) is satisfied in the step S240 (when the expression (1) and the expression (2) are satisfied, or when only the expression (2) is satisfied), the expression (2 ) Is not satisfied (when only equation (1) is satisfied), and the blinking pattern of the LED 180 is different. In this way, it is easy to determine whether the blinking of the LED 180 means that the remaining battery level is low or that the pump Px is abnormal. be able to. The LED 180 only needs to emit light in a different manner depending on whether or not the expression (2) is satisfied. The difference in the light emission mode may be, for example, a difference between lighting and blinking, or a difference in emission color.

  In this way, by blinking the LED 180, the monitoring person who looks around the installation site of the device can easily notice that the remaining battery level is low or that the pump Px is abnormal. When the remaining battery level is low, the battery can be replaced before the remaining battery level is exhausted. For this reason, although the sensor node SNx has an abnormality, the effective value RMS cannot be transmitted from the sensor node SNx to the server SV due to the remaining battery level remaining. It is possible to prevent the abnormality from being overlooked.

  In addition, when the remaining amount of the battery is very small or when there is an abnormality in the pump Px, the voltage value V and the effective value RMS are promptly transmitted to the server SV in step S280. Event can be quickly grasped and dealt with on the server SV side. In addition, when the supervisor moves to the installation site for countermeasures and performs work, even if the same type or similar type of pumps Px are collectively arranged, any sensor node SNx or pump Px can handle the problem. It is possible to easily grasp whether it is a target. In a factory, since the lighting is often dark and the noise is often large, the notification by the light emitting means is particularly effective.

  When the LED 180 is blinked, the CPU 110 determines whether or not the determination in step S240 satisfies the formula (2) (step S300). As a result of the determination, if the expression (2) is satisfied (step S300: YES), that is, if the remaining battery level is low, the CPU 110 ends the measurement value transmission process. Since the CPU 110 ends the measurement value transmission process without going through step S270, the CPU 110 does not enter the sleep mode and the power is constantly supplied to each part of the sensor node SNx. That is, the LED 180 blinks continuously thereafter. With such a configuration, the LED 180 is continuously blinked without returning to the sleep mode, so that the supervisor can easily identify the sensor node SNx or the pump Px that needs to be dealt with. Note that the CPU 110 may continue to supply power to only the LED 180 as a process of the control unit 111. In this way, power consumption can be reduced and the battery life can be extended. Further, a configuration may be adopted in which subsequent measurement value transmission processing is prohibited by setting a flag in the register of the CPU 110. In this way, power consumption can be further suppressed.

  On the other hand, if the expression (2) is not satisfied (step S300: NO), that is, if only the abnormality of the pump Px occurs, the CPU 110 shifts the operation state of the sensor node SNx to the standby mode. (Step S310), the measured value transmission process is terminated. The standby mode is a mode for waiting for the occurrence of a predetermined event for shifting to the sleep mode while continuing to blink the LED 180. That is, the standby mode is a mode for shifting to the sleep mode when a predetermined event occurs. The predetermined event is determined in advance, and in this embodiment, a predetermined time registered in the memory 170 has elapsed since the start of blinking of the LED 180. However, the predetermined event may be an instruction received from the server SV instead of or in addition to the elapse of a predetermined time registered in the memory 170 in advance. The instruction from the server SV may be an instruction to shift to the hibernation mode immediately, or an instruction to shift to the hibernation mode after a predetermined time elapses. In the standby mode, the supply of power may be continued only to the LED 180 in each part of the sensor node SNx that stops the power supply in the sleep mode. In such a case, the instruction from the server SV can be given when the measured value transmission process is executed again and the server SV is accessed from the sensor node SNx. With these configurations, the LED 180 does not blink continuously after the inspection of the equipment by the supervisor is completed, so that confusion with the pump Px where an abnormality has occurred and the inspection has not been completed can be suppressed. In addition, the battery life can be extended. In addition, since it is not necessary to provide the sensor node SNx with input means for inputting an instruction to stop the light emission to the sensor node SNx, the configuration of the sensor node SNx can be simplified.

B. Variation:
A modification of the above embodiment will be described.
B-1. Modification 1:
A power saving mode may be appropriately employed instead of the above-described sleep mode. The content of the power saving mode may be set as appropriate. For example, when the effective value RMS is recorded in the volatile memory, the power supply to the volatile memory may be constantly performed. Of course, power may be constantly supplied to each part of the sensor node SNx.

B-2. Modification 2:
In the above-described embodiment, the control unit 111 is configured to supply power to each part of the sensor node SNx when a signal is transmitted from the RTC 190 in the sleep mode of the sensor node SNx. These may be set as appropriate. For example, power may be supplied to the wireless communication module 160 only when the process of step S280 is performed.

B-3. Modification 3:
The timing for transmitting the effective value RMS and the voltage value V can take various forms. For example, it may be transmitted to the server SV every time measurement is performed. Alternatively, the measurement data is accumulated in the memory 170 until the expression (1) or the expression (2) is satisfied, and when the expression (1) or the expression (2) is satisfied, the measurement data up to that point is collectively collected. , It may be transmitted to the server SV.

  Moreover, it is good also as a structure which performs the 1st measurement for performing abnormality determination of the pump Px or a battery voltage fall determination, and the 2nd measurement for performing regular report of measurement data to the server SV. Such a configuration may be implemented, for example, in the following manner. The frequency of the first measurement is set higher than the frequency of the second measurement. In the first measurement, when an abnormality of the pump Px or a battery voltage decrease event is detected, the sensor node SNx transmits measurement data at that time to the server SV. On the other hand, if these events are not detected, the sensor node SNx discards the measurement data. In the second measurement, the sensor node SNx transmits measurement data to the server SV at the timing of either the above-described embodiment or the present modification. In this way, the above-described phenomenon can be grasped more quickly on the server SV side.

B-4. Modification 4:
The measurement data transmitted from the sensor node SNx to the server SV can be set as appropriate. For example, instead of the effective value RMS, a frequency spectrum may be calculated and transmitted. The measurement data to be transmitted can be measured values of various sensors. Such sensors can be, for example, temperature sensors, sound pressure sensors, AE (Acoustic Emission) sensors, displacement sensors, strain sensors, pressure sensors, water level sensors, current sensors, voltage sensors, and the like. The sensor may be any sensor that measures a physical quantity that reflects the operating state of the device. Of course, the sensor node SNx may include a plurality of sensors. Also, the device to which the sensor node SNx is attached is not limited to the pump, and can be various rotating system devices such as a motor, a blower, and a rotary cutting machine. Of course, the present invention is not limited to rotating equipment, and can be applied to various equipment.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment, A various structure can be taken in the range which does not deviate from the meaning. For example, the elements in the embodiments corresponding to the constituent elements of the application examples described above are appropriately used in an aspect that can solve at least a part of the problems of the present application or an aspect that exhibits at least a part of the effects described above. Combinations, omissions, and superordinate concepts are possible.

20 ... Device monitoring system 110 ... CPU
DESCRIPTION OF SYMBOLS 111 ... Control part 112 ... Transmission timing control part 113 ... Abnormality determination part 120 ... Battery box 130 ... Power supply circuit 140 ... Vibration sensor 150 ... Sampling circuit 160 ... Wireless communication module 170 ... Memory 180 ... LED
190 ... RTC
SN1 to SN12 ... sensor nodes P1 to P12 ... pump SV ... server GW1, GW2 ... gateway LAN ... local area network

Claims (8)

A sensor node of a plurality of sensor nodes for monitoring the device,
A sensor for measuring a physical quantity that reflects the operating state of the device;
A storage unit for storing information based on a measurement result of the sensor;
A wireless communication unit that transmits information based on the measurement result of the sensor to the monitoring device by wireless communication at a predetermined timing ; and
A battery accommodating portion for accommodating a battery as a power source of the sensor node;
A voltage detector for detecting a voltage value of the battery;
A light emitting unit that continuously emits light when the detected voltage value is equal to or lower than a predetermined value, and notifies the position of the sensor node ;
The wireless communication unit, when the detected voltage value becomes a predetermined value or less, regardless of the predetermined timing, the voltage value or information indicating that the voltage value has become the predetermined value or less And a sensor node that transmits information based on the measurement result that has not been transmitted to the monitoring device stored in the storage unit to the monitoring device, and stops subsequent wireless communication . The sensor node according to claim 1, wherein
A control unit for controlling the operation of the sensor node;
The controller is
A first control for supplying the power to the sensor at a predetermined time or in a predetermined cycle, and stopping the supply of the power to the sensor after measurement by the sensor;
The power is supplied to the wireless communication unit after the power is supplied to the wireless communication unit, the measurement by the sensor is performed, and the information based on the measurement result is transmitted by the wireless communication unit after the measurement. A sensor node that performs at least one of the second control for stopping the supply of the sensor. A claim 1 or claim 2 Symbol placement of sensor nodes,
A transmission timing control unit for controlling the timing of transmission of information based on the measurement result by the wireless communication unit;
The transmission timing control unit does not transmit information based on the measurement result of the first measurement to the monitoring device after the first measurement by the sensor, and is performed after the first measurement. After the measurement of the sensor node, control in a first mode is possible in which information based on the measurement results of the first measurement and the second measurement is collectively transmitted to the monitoring device. The sensor node according to claim 3 , wherein
An abnormality determination unit that determines abnormality of the device based on the measurement result of the sensor,
The transmission timing control unit is a mode that is executed when the device is determined to be abnormal, and the measurement corresponding to the determination of the device abnormality when the device is determined to be abnormal. Control in a second mode in which information based on the result is transmitted to the monitoring device together with information based on the measurement result that has been stored in the storage unit and has not been transmitted to the monitoring device is possible. A claim 1 or claim 2 Symbol placement of sensor nodes,
An abnormality determination unit that determines abnormality of the device based on the measurement result of the sensor,
The wireless communication unit, when the device is determined to be abnormal, and transmits the information based on the measurement result to the monitoring device,
The information based on the measurement result to be transmitted includes information based on the measurement result corresponding to the determination that the abnormality is present, and information based on the measurement result stored in the storage unit. The sensor node according to claim 4 or 5 , wherein
The abnormality determination unit is based on the degree of deviation between the information based on the measurement result acquired by a new measurement and the moving average value of the information based on the measurement result for a predetermined number of times stored in the storage unit. A sensor node that determines whether the device is abnormal. Equipment monitoring system comprising a plurality of said sensor nodes, wherein the said monitoring device in any one of claims 1 to 6. Comprising a sensor for measuring a physical quantity that reflects the operation state of the apparatus, and a storage unit for storing information based on the measurement result in the sensor, one sensor node of the plurality of sensor nodes to power the battery In the monitoring system that monitors the device by transmitting information based on the measurement result of the sensor to the monitoring device by wireless communication at a predetermined timing, the sensor node reports a decrease in the remaining battery level. A method for notifying a low battery level,
Detecting the voltage value of the battery;
When the detected voltage value is equal to or lower than a predetermined value, the light emitting unit included in the sensor node is continuously caused to emit light, and the position of the sensor node is notified ,
When the detected voltage value is equal to or less than a predetermined value, the voltage value or information indicating that the voltage value is equal to or less than the predetermined value regardless of the predetermined timing, and the storage unit A battery remaining power low notification method of transmitting information stored in the monitoring device that has not been transmitted to the monitoring device to the monitoring device and stopping subsequent wireless communication .

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