Battery voltage monitoring device and flow rate measuring device provided with same

Abstract

A battery voltage monitoring device (10) comprises a battery voltage monitoring unit (11) that monitors a terminal voltage of a power load battery (16), a load voltage monitoring unit (12) that monitors an applied voltage supplied to a power load (17), and a control unit (13). When the control unit (13) determines that the terminal voltage has dropped below a predetermined first notification threshold value, the control unit (13) generates first alarm information as notification information. When the control unit (13) determines that the applied voltage is lower than a second notification threshold value that is smaller than the first notification threshold value and is greater than a minimum guaranteed voltage that is the lowest value of the applied voltage at which the power load can operate, the control unit (13) generates second alarm information as the notification information. Thus, it is possible to effectively avoid or suppress excessive alarm notifications about the consumption of a battery. The battery voltage monitoring device (10) is applied to, for example, a flow rate measuring device.

Description

Battery voltage monitoring device and flow rate measuring device equipped with the same

[0001] The present invention relates to a battery voltage monitoring device that is applied to equipment powered by a battery and monitors the voltage of the battery, and to a flow rate measuring device that is a representative example of such equipment.

[0002] In devices that operate on power supplied from a battery (for convenience of explanation, referred to as "battery-powered devices"), the battery voltage has traditionally been monitored to assess battery consumption. A typical example is a method of detecting the battery voltage and comparing the detected value with a preset threshold to assess battery consumption.

[0003] For example, Patent Document 1 discloses a battery terminal voltage drop detection device that uses a voltage monitoring means to monitor the terminal voltage of a battery and detects when the terminal voltage drops below a reference voltage (threshold). This detection device allows the circuit current consumption of a battery-powered electronic device (battery-operated device) to be switched between multiple stages, and monitors the battery terminal voltage at each stage by comparing it with a reference voltage (threshold). This allows the user to be notified of the battery's level of depletion in a manner appropriate for each stage.

[0004] Japanese Patent Application Publication No. 04-225184

[0005] The threshold for monitoring the battery terminal voltage is generally set based on the lowest voltage value (minimum operating voltage) within the voltage range (operating voltage) in which the battery-powered device can operate. However, taking into account battery voltage fluctuations, this threshold is usually set to a value that allows for a certain margin from the minimum value, rather than a value just before the minimum value.

[0006] Depending on the type of battery-powered device, the battery's power supply voltage may be lowered. In such cases, both the terminal voltage of the battery being monitored and the threshold value, which allows for a margin, are relatively higher than the actual operating voltage of the battery-powered device. As a result, even if the terminal voltage being monitored is equal to or higher than the minimum operating voltage of the battery-powered device, it may be detected as being lower than the threshold value. This could result in the battery being evaluated as being depleted even if it is actually usable, resulting in an excessive alarm being issued to the user.

[0007] The present disclosure has been made to solve such problems, and aims to provide a battery voltage monitoring device that can effectively avoid or suppress excessive alarms regarding battery depletion.

[0008] In order to solve the above-mentioned problems, the battery voltage monitoring device of the present disclosure comprises a battery voltage monitoring unit that monitors the terminal voltage of a battery, a load voltage monitoring unit that monitors the applied voltage supplied from the battery to a power load, and a control unit, wherein the control unit generates first alarm information as alarm information when it determines that the terminal voltage monitored by the battery voltage monitoring unit has dropped below a predetermined first alarm threshold, and generates second alarm information as alarm information when it determines that the applied voltage monitored by the load voltage monitoring unit has dropped below a second alarm threshold that is lower than the first alarm threshold and higher than a minimum guaranteed voltage, which is the lowest value of applied voltage at which the power load can operate.

[0009] According to the above configuration, not only the terminal voltage of the battery serving as the power source is monitored, but also the voltage (applied voltage) supplied to the power load is monitored. A second notification threshold lower than the first notification threshold is set based on the lowest applied voltage at which the power load can operate. This allows battery depletion warning information to be generated based on not only the battery but also the power load. Therefore, even if the monitored value (measured value) of the battery terminal voltage does not adequately correspond to the operating voltage of the power load, the possibility of excessive battery depletion warnings can be effectively avoided or reduced.

[0010] Furthermore, with the above configuration, since both the voltage applied to the power load and the voltage of the battery are monitored, first alarm information can be generated based on a drop in the battery voltage, and second alarm information can be generated based on a drop in the voltage applied to the power load. This makes it possible to generate alarm information in two stages to notify the user of the battery-powered device that the remaining battery power is low. Therefore, for example, it is possible to change the weighting of the content of the alarm information between the first alarm information and the second alarm information.

[0011] The flow rate measurement device according to the present disclosure may be configured to include a battery voltage monitoring device having the above-described configuration, a flow rate measurement unit that measures the flow rate of a fluid, and an alarm unit that issues an alarm based on the alarm information.

[0012] According to the above configuration, the load voltage monitoring unit monitors the applied voltage of the battery that supplies power to the power load of the flow measurement device, and a second notification threshold can be set. This allows battery depletion in the flow measurement device to be generated as warning information based not only on the battery but also on the power load. This effectively avoids or reduces the possibility of issuing excessive warnings regarding battery depletion. Furthermore, the user of the flow measurement device can be notified of battery depletion in two stages: a first warning and a second warning. Therefore, for example, it is possible to change the weighting of the warning information for the first warning and the second warning.

[0013] The above and other objects, features, and advantages of the present disclosure will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.

[0014] With the above configuration, the present disclosure has the effect of providing a battery voltage monitoring device that can effectively avoid or suppress excessive issuance of alarms regarding battery depletion.

[0015] FIG. 1 is a block diagram showing a typical example of the configuration of a battery voltage monitoring device according to a first embodiment of the present disclosure. FIG. 2A is a schematic circuit diagram showing an example of a circuit configuration near a battery of the battery voltage monitoring device shown in FIG. 1 , and FIG. 2B is a schematic circuit diagram showing an example of a circuit configuration near a battery of a conventional battery voltage monitoring device. FIG. 3A is a flowchart showing a typical example of a battery voltage monitoring method using the battery voltage monitoring device shown in FIG. 1 , and FIG. 3B is a flowchart showing a typical example of a battery voltage monitoring method using a conventional battery voltage monitoring device. FIG. 4 is a graph showing changes in battery voltage over time, including examples of first and second notification thresholds set in the battery voltage monitoring device shown in FIG. 1 . FIG. 5 is a block diagram showing a typical example of the configuration of a flow measurement device (a battery-powered device including a battery voltage monitoring device) according to a second embodiment of the present disclosure. FIG. 6 is a schematic circuit diagram showing an example of a circuit configuration near a battery of the flow measurement device shown in FIG. 5 . FIG. 7 is a flowchart showing a typical example of a battery voltage monitoring method using the flow measurement device shown in FIG. 5 . Fig. 8 is a graph showing a change in battery voltage over time, including an example of a remaining time that is a time during which power can be supplied from a battery, in a flow measurement device according to a third embodiment of the present disclosure. Fig. 9 is a flowchart showing a representative example of a battery voltage monitoring method using a flow measurement device according to the third embodiment. Fig. 10A is a graph showing a change in battery voltage over time, including an example of a remaining time that is a time during which power can be supplied from a battery, in a flow measurement device according to a fourth embodiment of the present disclosure. Fig. 10B is a schematic enlarged view of a graph showing an example of a decrease in battery voltage in a region surrounded by a dashed line in Fig. 10A. Fig. 11 is a flowchart showing a representative example of a battery voltage monitoring method using a flow measurement device according to the fourth embodiment.

[0016] Representative embodiments of the present disclosure will be described below with reference to the drawings. Note that the same or corresponding elements will be designated by the same reference numerals throughout the drawings, and redundant description thereof will be omitted.

[0017] (Embodiment 1) A representative example of a battery voltage monitoring device according to this embodiment 1 will be described with reference to Figure 1. The battery voltage monitoring device 10 shown in Figure 1 includes a battery voltage monitoring unit 11, a load voltage monitoring unit 12, a control unit 13, a memory unit 14, a notification unit 15, a power load battery 16, and a power load 17. This battery voltage monitoring device 10 is mounted on a device (battery-powered device) that operates by receiving power from a replaceable battery. The specific configuration of the battery-powered device is not particularly limited. In embodiments 2 to 4 described below, a flow rate measurement device such as a gas meter or a water meter is used as an example of the battery-powered device.

[0018] In the first embodiment, the power load battery 16 is replaceable in the battery-powered device and supplies power to the load voltage monitoring unit 12. The specific configuration of the power load 17 is not particularly limited as long as it operates when power is supplied from the load voltage monitoring unit 12. In the second to fourth embodiments described below, the battery-powered device is a flow measurement device, and in this case, a communication unit (more specifically, an RF circuit provided in the communication unit) is exemplified as the power load 17. An example of the power load battery 16 that supplies power to such a communication unit is a replaceable lithium-ion battery. Note that the power load battery 16 is not limited to a replaceable battery, and a non-replaceable battery may be provided in the battery-powered device.

[0019] The battery voltage monitoring unit 11 monitors the terminal voltage of the power load battery 16 and outputs the monitoring result to the control unit 13. The load voltage monitoring unit 12 monitors the applied voltage supplied from the power load battery 16 to the power load 17 and outputs the monitoring result to the control unit 13. The specific configurations of the battery voltage monitoring unit 11 and the load voltage monitoring unit 12 are not particularly limited, and known voltage monitoring circuits can be suitably used.

[0020] The control unit 13 controls the operation of the battery voltage monitoring device 10, and the storage unit 14 stores application software (programs) and data required for control by the control unit 13. The specific configuration of the control unit 13 is not particularly limited, and may be a general-purpose processor, a dedicated processor, an integrated circuit, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuits), a GPU, or the like, either alone or in combination of two or more types, as long as it operates to realize its control function in accordance with a program stored in a storage device (storage unit 14).

[0021] Such a processor as an arithmetic device is a hardware circuit (or processing circuit) because it includes a circuit configured with a large number of transistors, memories, etc. Integrated circuits or ASICs are also hardware circuits because they include processors or processing blocks such as CPUs. FPGAs are hardware circuits because they include a large number of integrated logic circuits (functional blocks). GPUs are hardware circuits because they include a large number of arithmetic circuits (cores) mounted in parallel. Software such as programs stored in a storage device is used to configure hardware circuits (processors, integrated circuits, FPGAs, ASICs, GPUs, etc.). Alternatively, the arithmetic device may be configured as a logic circuit or the like using known switching elements, subtractors, comparators, etc.

[0022] The specific configuration of the storage unit 14 is not particularly limited, and may be configured as an internal memory of a microcomputer or a microcontroller unit (MCU), or may be configured as an independent memory. Furthermore, the storage unit 14 does not need to be a single unit, and may be configured as multiple storage devices.

[0023] Based on the results of monitoring the terminal voltage and the applied voltage, the notification unit 15 issues an alarm to the user of the battery-operated device under the control of the control unit 13. As will be described later, the control unit 13 generates notification information based on the monitoring results input from the battery voltage monitoring unit 11 or the load voltage monitoring unit 12 and outputs this to the notification unit 15, which then issues an alarm based on this notification information.

[0024] The specific configuration of the notification unit 15 is not particularly limited, and examples include known notification means, such as a display such as a liquid crystal display, an audio alarm, or a combination of these. The notification unit 15 may be a configuration that is unique to the battery voltage monitoring device 10, or may also serve as a notification unit provided in the battery-powered device. In the second to fourth embodiments described below, a notification unit provided in a flow measurement device, which is a battery-powered device, is also used as the notification unit of the battery voltage monitoring device 10.

[0025] Similarly to the notification unit 15, the control unit 13 and the storage unit 14 may be configured to be provided independently by the battery voltage monitoring device 10, or a control unit and a storage unit provided in the battery-powered device may function as the control unit 13 and the storage unit 14 of the battery voltage monitoring device 10. In this case, at least the control unit 13 of the battery voltage monitoring device 10 is realized as software (application program) of the battery-powered device.

[0026] Therefore, when the battery voltage monitoring device 10 according to the present disclosure is applied to a battery-powered device, the control unit of the battery-powered device only needs to be configured to implement the battery voltage monitoring function as one of the controls of the device. In the second to fourth embodiments described below, the control unit and memory unit provided in the flow measurement device, which is a battery-powered device, function as the control unit and memory unit of the battery voltage monitoring device 10.

[0027] Next, an example of a battery voltage monitoring method using the battery voltage monitoring device 10 according to the first embodiment will be described with reference to FIGS. 2A, 2B, 3A, 3B, and 4, in comparison with a conventional example.

[0028] In the battery voltage monitoring device 10 according to the first embodiment, as shown schematically in Fig. 2A, a battery voltage monitoring unit 11 is connected in parallel to a power load battery 16, and a load voltage monitoring unit 12 is connected to the power supply side to a power load 17. In the configuration shown in Fig. 2A, an MCU (Micro Controller Unit) 20 provided in the battery-powered device functions as the control unit 13 of the battery voltage monitoring device 10, and the monitoring results from the battery voltage monitoring unit 11 and the load voltage monitoring unit 12 are output to the MCU 20. In the example shown in Fig. 2A, power is supplied separately to the MCU 20 from a battery 18 installed in the battery-powered device.

[0029] On the other hand, in a conventional battery voltage monitoring device, as shown schematically in Fig. 2B, a battery voltage monitoring unit 11 is connected in parallel to a power load battery 16, and the monitoring results from the battery voltage monitoring unit 11 are simply output to an MCU 20, without including a load voltage monitoring unit 12. Note that in Fig. 2B, as in Fig. 2A, power is supplied to a power load 17 from a power load battery 16, and power is supplied to an MCU 20 from a battery 18 mounted on a battery-operated device.

[0030] In addition, when the battery-operated device is a flow measurement device, the power load battery 16 is provided so as to be replaceable, but the battery 18 mounted on the battery-operated device is not replaceable, and can be configured to be operable for the same period as the replacement life of the flow measurement device (generally 10 years or more).

[0031] First, a battery voltage monitoring method using a conventional battery voltage monitoring device will be described with reference to Fig. 3B. A battery-powered device equipped with a conventional battery voltage monitoring device is installed under predetermined conditions according to its intended use (step S01), and then initialized (step S02). In the example shown in Fig. 3B, the battery-powered device exemplified in the second to fourth embodiments described below is an example of a flow measurement device, and the flow measurement device is installed in a market such as a gas or water supply (install in field) and initialized (initialization).

[0032] Next, the battery-powered device starts a predetermined operation (step S03). With this operation starting, the power load 17 included in the battery-powered device receives power from the power load battery 16 and starts operating. In the example shown in Fig. 3B, a communication unit included in the flow measurement device wirelessly connects to the base station (RF connection) and then transitions to standby mode (PSM, Power Save Mode). Therefore, in the example of the flow measurement device, the communication unit corresponds to the power load 17.

[0033] Next, the terminal voltage Vbat of the power load battery 16, which is the monitoring result from the battery voltage monitoring unit 11, is output to the MCU 20 (control unit 13), and the MCU 20 compares this terminal voltage Vbat with a preset first notification threshold Vth1 (Vbat < Vth1, step S04). The first notification threshold Vth1 may be any predetermined voltage value that is set in advance, but typically it can be set based on the practical lower limit of the terminal voltage of the power load battery 16. This first notification threshold Vth1 serves as a reference value for determining whether or not to notify the power load battery 16 that it is depleted.

[0034] If it is not determined that the terminal voltage Vbat has dropped below the first notification threshold Vth1 (no in step S04), the battery-powered device continues its predetermined operation (return to step S03). On the other hand, if it is determined that the terminal voltage Vbat has dropped below the first notification threshold Vth1 (yes in step S04), the MCU 20 (control unit 13) generates alarm information as notification information and outputs it to the notification unit 15 (see FIG. 1). The notification unit 15 then issues an alarm based on this alarm information (Send alarm, step S05). The user of the battery-powered device then acknowledges this alarm and replaces the power load battery 16 (Battery change, step S06). This completes the battery voltage monitoring method using a conventional battery voltage monitoring device.

[0035] 4 shows a schematic graph in which the voltage (battery voltage) of the power load battery 16 is plotted on the vertical axis and the time during which power is supplied by the power load battery 16 is plotted on the horizontal axis. If the lowest applied voltage at which the power load 17 can operate is defined as a minimum guaranteed voltage Vmin, then as shown in FIG. 4, the first notification threshold Vth1 of the terminal voltage is set to a voltage value with a large margin above the minimum guaranteed voltage Vmin.

[0036] Therefore, the time when the battery voltage reaches the first notification threshold Vth1 is defined as t1, and the time when the battery voltage reaches the minimum guaranteed voltage Vmin is defined as t est In this case, the MCU 20 (control unit 13) generates alarm information when time t1 is reached, and the alarm unit 15 issues an alarm based on this alarm information. The user replaces the power load battery 16 based on the alarm issued at time t1. However, as shown in Figure 4, the power load battery 16 still has some capacity left to supply power at time t1. Therefore, with the conventional battery voltage monitoring method, even if the power load battery 16 is actually usable, it is evaluated as being depleted, and the battery-powered device issues an excessive alarm to the user.

[0037] Next, a battery voltage monitoring method using the battery voltage monitoring device 10 according to the first embodiment will be described with reference to Fig. 3A. As shown in Fig. 3A, a battery-powered device incorporating the battery voltage monitoring device 10 is installed under predetermined conditions according to its intended use (step S11), initialized (step S12), and starts a predetermined operation (step S13).

[0038] In the example shown in FIG. 3A , similarly to FIG. 3B , the battery-operated device is an example of a flow measurement device, and the flow measurement device is installed in a market such as a gas or water supply market (Install in field, step S11) and initialized (Initialization, step S12), after which a communication unit provided in the flow measurement device wirelessly connects to a base station (RF connection, step S13) and transitions to a standby mode (PSM, step S13).

[0039] Next, as shown in FIG. 3A, the terminal voltage Vbat of the power load battery 16 is output to the MCU 20 (control unit 13), and the MCU 20 compares this terminal voltage Vbat with the first notification threshold Vth1 (Vbat<Vth1, step S14).

[0040] If it is not determined that the terminal voltage Vbat has dropped below the first alarm threshold Vth1 (no in step S14), the battery-powered device continues to operate as intended (return to step S13). If it is determined that the terminal voltage Vbat has dropped below the first alarm threshold Vth1 (yes in step S14), the MCU 20 (controller 13) generates first alarm information as alarm information and outputs it to the alarm unit 15 (see FIG. 1), and the alarm unit 15 issues a first alarm based on this first alarm information (Send 1st alarm, step S15). Up to this point, the method is substantially the same as the conventional battery voltage monitoring method shown in FIG. 3B.

[0041] Thereafter, the predetermined operation of the battery-operated device continues (RF connection & PSM, step S16), and the applied voltage V applied to the power load 17, which is the monitoring result from the load voltage monitoring unit 12, is LD is output to the MCU 20 (control unit 13), and the MCU 20 detects this applied voltage V LD is compared with a preset second notification threshold value Vth2 (V LD <Vth2, step S17). Like the first notification threshold Vth1, the second notification threshold Vth2 is a reference value for determining whether or not to notify the user of the consumption of the power load battery 16, and may be a predetermined value that is set in advance, like the first notification threshold Vth1.

[0042] However, the second notification threshold Vth2 is set to a value smaller than the first notification threshold Vth1. As described above, if the MCU 20 (control unit 13) determines that the terminal voltage Vbat has dropped below the first notification threshold Vth1, it generates first alarm information as notification information. Furthermore, in the present disclosure, the second notification threshold Vth2 is set to generate second alarm information after generating the first alarm information, and therefore, as shown in FIG. 4, the second notification threshold Vth2 is set to a value smaller than the first notification threshold Vth1. Furthermore, the second notification threshold Vth2 can be set based on the minimum guaranteed voltage Vmin, which is the lowest applied voltage at which the power load 17 can operate.

[0043] Applied voltage V LD If it is not determined that the applied voltage V has fallen below the second notification threshold Vth2 (no in step S17), the predetermined operation of the battery-operated device continues (return to step S16). LD If it is determined that Vth2 has fallen below the second notification threshold Vth2 (yes in step S17), the MCU 20 (control unit 13) generates second alarm information as notification information and outputs it to the notification unit 15 (see FIG. 1). The notification unit 15 issues a second alarm based on this second alarm information (Send 2nd alarm, step S18). The user of the battery-powered device confirms this second alarm and replaces the power load battery 16 (Battery change, step S19). This completes the battery voltage monitoring method using the battery voltage monitoring device 10 according to the first embodiment.

[0044] In particular, the second notification threshold Vth2 can be set based on the applied voltage of the power load 17. Therefore, as shown in Figure 4, the second notification threshold Vth2 can be set closer to the minimum guaranteed voltage Vmin of the power load 17 compared to the first notification threshold Vth1 which is based on the terminal voltage of the power load battery 16.

[0045] Even if an alarm is issued only at the timing t1 of the first alarm threshold Vth1 as in the conventional case, the timing t1 at which the voltage of the power load battery 16 drops to the minimum guaranteed voltage Vmin is not reached. estBy this time, it is possible to supply enough power to operate the power load 17. Therefore, issuing an alarm at timing t1 would be excessive as an alarm for replacing the power load battery 16.

[0046] In contrast, in the present disclosure, the MCU 20 (controller 13) generates second alarm information at timing t2, and the alarm unit 15 issues a second alarm based on this second alarm information. Therefore, the alarm unit 15 can issue an alarm at timing t2 of the second alarm threshold Vth2. This allows the alarm issuance time (timing t2) to be set to the timing t est This makes it possible to effectively avoid or reduce the risk of excessive issuance of an alarm to replace the power load battery 16. Furthermore, in the present disclosure, since an alarm can be issued even at timing t1 of the first alarm threshold Vth1, it is possible to change the weighting of the alarm content between the first alarm issued at timing t1 and the second alarm issued at timing t2.

[0047] As described above, the battery voltage monitoring device 10 according to the first embodiment includes a battery voltage monitoring unit 11 that monitors the terminal voltage of the power load battery 16, a load voltage monitoring unit 12 that monitors the applied voltage supplied from the power load battery 16 to the power load 17, a control unit 13, a memory unit 14, and a notification unit 15. When the control unit 13 determines that the terminal voltage monitored by the battery voltage monitoring unit 11 has dropped below a predetermined first notification threshold, it generates first alarm information as notification information. Furthermore, when the control unit 13 determines that the applied voltage monitored by the load voltage monitoring unit 12 has dropped below a second alarm threshold that is lower than the first notification threshold and higher than a minimum guaranteed voltage that is the lowest value of the applied voltage at which the power load 17 can operate, it generates second alarm information as notification information. The notification unit 15 issues a first alarm or a second alarm based on the alarm information.

[0048] This allows the battery voltage monitoring device 10 to evaluate the depletion of the power load battery 16 based not only on the power load battery 16 itself but also on the power load 17. Therefore, even if the monitored value (measured value: Vbat) of the terminal voltage of the power load battery 16 does not adequately correspond to the operating voltage of the power load 17, it is possible to effectively avoid or reduce the possibility of excessive issuance of an alarm regarding the depletion of the power load battery 16.

[0049] In the first embodiment, the battery voltage monitoring device 10 detects the applied voltage V LD and the voltage (terminal voltage Vbat) of the power load battery 16, a drop in the voltage of the power load battery 16 can be set as a first alarm, and a drop in the applied voltage of the power load 17 can be set as a second alarm. This makes it possible to issue a two-stage alarm to the user of the battery-operated device informing them that the remaining charge of the power load battery 16 is low. Therefore, for example, it is possible to change the weighting of the alarm content between the first alarm and the second alarm.

[0050] As shown in FIG. 1 , the battery voltage monitoring device 10 according to the first embodiment includes a battery voltage monitoring unit 11, a load voltage monitoring unit 12, a control unit 13, a memory unit 14, a notification unit 15, a power load battery 16, and a power load 17. However, for example, the notification unit 15, the power load battery 16, and the power load 17 may not be included. When the battery voltage monitoring device 10 is incorporated into a battery-powered device, it is sufficient to connect the battery voltage monitoring unit 11 and the load voltage monitoring unit 12 to the notification unit 15, the power load battery 16, and the power load 17 included in the battery-powered device, and therefore the notification unit 15, the power load battery 16, and the power load 17 are not essential. As described above, the power load battery 16 may be replaceable or non-replaceable.

[0051] (Embodiment 2) In the above-described embodiment 1, a typical example of the basic configuration of the battery voltage monitoring device 10 according to the present disclosure was described. In this embodiment 2, the flow measurement device described above is used as a typical example of a battery-powered device, and a typical example in which the battery voltage monitoring device 10 according to the present disclosure is applied to a flow measurement device is described.

[0052] 5 , a flow rate measurement device 30 according to the second embodiment includes a battery voltage monitoring unit 21, a load voltage monitoring unit 22, a control unit 23, a storage unit 24, a notification unit 25, a communication battery 26, an RF circuit 27, an antenna 28, a flow rate measurement unit 31, and a flow rate measurement battery 32. The RF circuit 27 and the antenna 28 configure a communication unit 29 of the flow rate measurement device 30.

[0053] In the second embodiment, the communication battery 26 is replaceably provided in the flow measurement device 30, and supplies power to the communication unit 29 (RF circuit 27 in FIG. 5 ). Therefore, in the flow measurement device 30 according to the second embodiment, the communication battery 26 corresponds to the power load battery 16 of the battery voltage monitoring device 10 (see FIG. 1 ). The RF circuit 27 operates by receiving power from the communication battery 26, and communicates wirelessly with other communication devices via the antenna 28. Therefore, the RF circuit 27 according to the second embodiment corresponds to the power load 17 of the battery voltage monitoring device 10 (see FIG. 1 ). As described above, the RF circuit 27 constitutes the communication unit 29, and therefore it can also be said that the communication unit 29 corresponds to the power load 17.

[0054] The specific configurations of the communication battery 26, RF circuit 27, and antenna 28 are not particularly limited, and configurations used in known gas meters, water meters, etc. can be suitably used. The communication battery 26 may be provided in the flow measurement device 30 in a replaceable manner, similar to the power load battery 16 in the first embodiment, but may also be provided in a non-replaceable manner. In the second embodiment, the communication unit 29 is configured by the RF circuit 27 and the antenna 28, but the configuration of the communication unit 29 of the flow measurement device 30 is not limited to this, and a configuration used in known gas meters, water meters, etc. can be suitably used. In the second embodiment, the communication unit 29 (RF circuit 27) is exemplified as the power load 17 to which power is supplied from the power load battery 16, but the power load 17 may have another configuration.

[0055] The battery voltage monitoring unit 21 monitors the terminal voltage of the communication battery 26 and outputs the monitoring result to the control unit 23. The load voltage monitoring unit 22 monitors the applied voltage supplied from the communication battery 26 to the RF circuit 27 and outputs the monitoring result to the control unit 23. The control unit 23 controls the operation of the flow measurement device 30, and the storage unit 24 stores application software (programs), data, etc. required for control by the control unit 23. The notification unit 25 issues an alarm to the user of the battery-operated device under the control of the control unit 23. As will be described later, the control unit 23 generates notification information based on the monitoring result input from the battery voltage monitoring unit 21 or the load voltage monitoring unit 22 and outputs it to the notification unit 25, and the notification unit 25 issues an alarm based on the notification information.

[0056] The specific configurations of the battery voltage monitoring unit 21, the load voltage monitoring unit 22, the control unit 23, the storage unit 24, and the notification unit 25 are not particularly limited. A representative example is a configuration similar to the battery voltage monitoring unit 11, the load voltage monitoring unit 12, the control unit 13, the storage unit 14, and the notification unit 15 provided in the battery voltage monitoring device 10 (see FIG. 1 ) described in the first embodiment. The flow rate measurement device 30 according to the second embodiment corresponds to the battery-powered device in the first embodiment. Therefore, the battery voltage monitoring device according to the second embodiment is configured by at least the battery voltage monitoring unit 21, the load voltage monitoring unit 22, and the control unit 23. The battery voltage monitoring unit 21 and the load voltage monitoring unit 22 may be configured to be realized as software (application programs) as functional components of the MCU, which is the control unit 23.

[0057] In particular, in the second embodiment (and also in the third and fourth embodiments described below), the RF circuit 27 of the communication unit 29 is cited as an example of the power load 17 (see FIG. 1 ). The RF circuit 27 may include an A / D converter (ADC). In this case, the ADC of the RF circuit 27 can be used as the load voltage monitoring unit 22 (or a part thereof). As a result, the load voltage monitoring unit 22 according to the present disclosure does not need to be provided with a separate hardware voltage monitoring sensor or the like, and can be substantially realized as a functional configuration (software configuration) of the MCU (control unit 23) provided in the flow measurement device 30. Note that a typical RF circuit 27 includes an ADC, but if the RF circuit 27 does not include an ADC, a separate ADC can be added.

[0058] The flow rate measurement unit 31 measures the flow rate of the fluid to be measured under the control of the control unit 23 and outputs the measurement result to the control unit 23. The flow rate measurement battery 32 supplies power to the flow rate measurement unit 31 and the control unit 23. The specific configurations of the flow rate measurement unit 31 and the flow rate measurement battery 32 are not particularly limited, and known configurations can be suitably used depending on the type of fluid to be measured. For example, if the fluid is a gas, the flow rate measurement device 30 is a gas meter, and therefore a known ultrasonic measurement unit can be used as the flow rate measurement unit 31. Furthermore, the flow rate measurement device 30 may include components other than the flow rate measurement unit 31 and the flow rate measurement battery 32. For example, if the flow rate measurement device 30 is a gas meter, it may include a sensor for detecting gas leaks, a shut-off valve, etc.

[0059] Next, an example of a battery voltage monitoring method executed by the flow rate measurement device 30 according to the second embodiment will be described with reference to FIGS. 6 and 7. FIG.

[0060] 6, in a flow measurement device 30 according to the second embodiment, a battery voltage monitoring unit 21 is connected in parallel to a communication battery 26, and a load voltage monitoring unit 22 is connected to the power supply side of an RF circuit 27. In the configuration shown in FIG. 6, an MCU 33 provided in the flow measurement device 30 functions as a control unit 23, and monitoring results from the battery voltage monitoring unit 21 and the load voltage monitoring unit 22 are output to the MCU 33.

[0061] Furthermore, the MCU 33 outputs control information for controlling the RF circuit 27 and the flow rate measurement unit 31, and also acquires wireless communication information from the RF circuit 27 or flow rate measurement information from the flow rate measurement unit 31 to control the operation of the flow rate measurement device 30. Furthermore, power is supplied separately to the MCU 33 and the flow rate measurement unit 31 from a flow rate measurement battery 32. Therefore, the flow rate measurement battery 32 corresponds to the battery-operated device mounted battery 18 (see FIG. 2A ) in the first embodiment.

[0062] 7, in the flow measurement device 30, first, the second notification threshold Vth2 is individually set according to the conditions, etc. (Customize Vth2, step S21). This second notification threshold Vth2 is stored in the memory unit 24. Next, the flow measurement device 30 in which the second notification threshold Vth2 has been set is installed in a gas or water market (Install in field, step S22) and initialized (Initialization, step S23). Thereafter, the communication unit 29 included in the flow measurement device 30 wirelessly connects to a base station and transitions to standby mode (RF connection & PSM, step S24).

[0063] Next, as shown in FIG. 7, the terminal voltage Vbat of the communication battery 26 is output to the MCU 33 (control unit 23), and the MCU 33 compares this terminal voltage Vbat with the first notification threshold Vth1 (Vbat<Vth1, step S25).

[0064] If it is not determined that the terminal voltage Vbat has dropped below the first notification threshold Vth1 (no in step S25), the flow measurement device 30 continues the wireless connection with the base station and the transition to standby mode (return to step S24).If it is determined that the terminal voltage Vbat has dropped below the first notification threshold Vth1 (yes in step S25), the MCU 33 (controller 23) generates first alarm information as notification information and outputs it to the alarm unit 25 (see FIG. 5), and the alarm unit 25 issues a first alarm based on this first alarm information (Send 1st alarm, step S26).

[0065] Thereafter, the flow rate measurement device 30 continues the operation of wireless connection with the base station and transition to the standby mode (RF connection & PSM, step S27), and the applied voltage V applied to the RF circuit 27, which is the monitoring result from the load voltage monitoring unit 22, is LD is output to the MCU 33 (control unit 23), and the MCU 33 detects this applied voltage V LD is compared with the second notification threshold Vth2 set initially (step S21) (V LD <Vth2, step S28).

[0066] Applied voltage V LD If it is not determined that the applied voltage V is lower than the second notification threshold Vth2 (no in step S28), the flow rate measurement device 30 continues the wireless connection with the base station and the transition operation to the standby mode (return to step S27). LD If it is determined that the voltage Vth2 has dropped below the second notification threshold Vth2 (yes in step S28), the MCU 33 (control unit 23) generates second alarm information as notification information and outputs it to the notification unit 25 (see FIG. 5). The notification unit 25 issues a second alarm based on this second alarm information (Send 2nd alarm, step S29). The user of the flow measurement device 30 confirms this second alarm and replaces the communication battery 26 (Battery change, step S30). This completes the battery voltage monitoring method using the flow measurement device 30 according to the second embodiment.

[0067] In the second embodiment, the control unit 23 (MCU 33) of the flow rate measurement device 30 generates first alarm information at timing t1 (see FIG. 4) of the first alarm threshold Vth1 as in the conventional case, and causes the alarm unit 25 to issue the first alarm, and generates second alarm information at timing t2 (see FIG. 4) of the second alarm threshold Vth2, and causes the alarm unit 25 to issue the second alarm. As a result, the timing (timing t2) of issuing the second alarm is set to the timing t est (See FIG. 4 ) This effectively avoids or reduces the risk of excessive issuance of an alarm to replace the communication battery 26.

[0068] Furthermore, in this second embodiment, as in the first embodiment, an alarm can be issued at both timing t1 of the first alarm threshold Vth1 and timing t2 of the second alarm threshold Vth2, so that the weighting of the alarm content can be changed for the first alarm information issued at timing t1 and the second alarm information issued at timing t2.

[0069] 7, the second notification threshold Vth2 can be set individually and stored in the storage unit 24. This allows the second notification threshold Vth2 to be set according to the conditions under which each individual flow measurement device 30 is installed. This makes it possible to issue a second alarm at a timing suitable for each individual flow measurement device 30.

[0070] In this third embodiment, in the battery voltage monitoring method executed by the flow measurement device 30 according to the second embodiment, the remaining time, which is the time during which power can be supplied from the communication battery 26 to the RF circuit 27, is further generated as notification information. A typical example of this configuration will be specifically described with reference to FIGS. 8 and 9.

[0071] For example, if the flow rate measuring device 30 is a gas meter, the wireless connection with a base station or the like by the communication unit 29 (see FIG. 5) and the transition to standby mode do not change significantly. Therefore, the amount of power consumed by the communication unit 29 does not change significantly over time, and even if the battery voltage of the communication battery 26 begins to decrease, the degree of the decrease can be approximated as a linear function change over time.

[0072] For example, as shown in FIG. 8, the period from when the battery voltage reaches the first notification threshold Vth1 to when the battery voltage reaches the second notification threshold Vth2 (the period from timing t1 to timing t2 / solid line in FIG. 8) is defined as Period 1, and the period from when the battery voltage reaches the second notification threshold Vth2 to when the battery voltage reaches the minimum guaranteed voltage Vmin (the period from timing t2 to timing t estThe period from Period 1 to Period 2 (dotted line in FIG. 8) is defined as Period 2. As shown in FIG. 8, the decrease in battery voltage in both Period 1 and Period 2 can be approximated by a straight line with a downward sloping slope. Therefore, the decrease in battery voltage from Period 1 to Period 2 can be approximated by a linear function change overall.

[0073] In this case, for example, by regarding the slope of the battery voltage drop in period 1 as being the same as the slope of the battery voltage drop in period 2, the time from when the second notification threshold Vth2 is reached to when the minimum guaranteed voltage Vmin is reached, i.e., the remaining time T est can be predicted by extrapolation.

[0074] For example, when the gradient of the battery voltage drop in period 1 is Gr1 and the gradient of the battery voltage drop in period 2 is Gr2, Gr1 can be expressed by the following formula (1), and Gr2 can be expressed by the following formula (2). Therefore, from these formulas (1) and (2), the remaining time T est Gr1=(Vth1-Vth2) / (t2-t1) (1) Gr2=(Vth2-Vmin) / (t est -t2)...(2)

[0075] An example of a battery voltage monitoring method having such a configuration will be described with reference to Fig. 9 in addition to Fig. 8. Note that the battery voltage monitoring method of the third embodiment differs from the battery voltage monitoring method described in the second embodiment (see Fig. 7) in that the remaining time T est The battery voltage monitoring method according to the present disclosure is not limited to this. For example, the battery voltage monitoring method according to the first embodiment (see FIG. 3A ) may be configured to add a step of calculating the remaining time T est It goes without saying that a step of calculating the above may be added.

[0076] 9, in the flow measurement device 30 (see FIG. 5), first, the second notification threshold Vth2 is individually set according to the conditions, etc. (Customize Vth2, step S31). This second notification threshold Vth2 is stored in the memory unit 24. Next, the flow measurement device 30 in which the second notification threshold Vth2 has been set is installed in a gas or water market (Install in field, step S32) and initialized (Initialization, step S33). Thereafter, the communication unit 29 included in the flow measurement device 30 wirelessly connects to a base station and transitions to standby mode (RF connection & PSM, step S34).

[0077] Next, the terminal voltage Vbat of the communication battery 26 is output to the MCU 33 (controller 23, see FIG. 6), and the MCU 33 compares this terminal voltage Vbat with the first notification threshold Vth1 (Vbat < Vth1, step S35). If it is not determined that the terminal voltage Vbat has dropped below the first notification threshold Vth1 (no in step S35), the flow measurement device 30 continues the wireless connection with the base station and the transition to standby mode (return to step S34).

[0078] If it is determined that the terminal voltage Vbat has dropped below the first alarm threshold Vth1 (YES in step S35), the MCU 33 (controller 23) generates first alarm information as alarm information and outputs it to the alarm unit 25 (see FIG. 5), and the alarm unit 25 issues a first alarm based on this first alarm information (Send 1st alarm, step S36). The steps up to this point are the same as those in the battery voltage monitoring method according to the second embodiment (see FIG. 7).

[0079] Here, the MCU 33 (control unit 23) stores the time when the first alarm information is generated and output to the alarm unit 15, that is, the time when the alarm unit 15 issues the first alarm (timing t1, see FIG. 8), as the first alarm time in the storage unit 24 (see FIG. 5) (Log current time = t1, step S37). After that, the flow rate measurement device 30 continues the operation of wirelessly connecting with the base station and transitioning to the standby mode (RF connection & PSM, step S38), and stores the applied voltage V to the RF circuit 27, which is the monitoring result from the load voltage monitoring unit 22, in the storage unit 24 (see FIG. 5) (Log current time = t1, step S37). LD is output to the MCU 33 (control unit 23), and the MCU 33 detects this applied voltage V LD is compared with the second notification threshold Vth2 set initially (step S31) (V LD <Vth2, step S39).

[0080] Applied voltage V LD If it is not determined that the applied voltage V has fallen below the second notification threshold Vth2 (no in step S39), the flow rate measurement device 30 continues the wireless connection with the base station and the transition operation to the standby mode (return to step S38). LD If it is determined that the second alarm threshold Vth2 has fallen below the second alarm threshold Vth2 (yes in step S39), the MCU 33 (control unit 23) generates second alarm information as alarm information and outputs it to the alarm unit 25 (see FIG. 5), and the alarm unit 25 issues a second alarm based on this second alarm information (Send 2nd alarm, step S40).

[0081] Here, the MCU 33 (controller 23) stores the time when the second alarm information is generated and output to the alarm unit 15, i.e., the time when the alarm unit 15 issues the second alarm (timing t2, see FIG. 8), as the second alarm time in the storage unit 24 (see FIG. 5) (Log current time = t2, step S41). Furthermore, using the first alarm time and the second alarm time, the MCU 33 (controller 23) calculates the time (remaining time) T during which power can be supplied by the communication battery 26, for example, using the above-mentioned formulas (1) and (2). est is generated as notification information (Estimate remaining time T est, step S42), and outputs the remaining time T est Send T est , step S43).

[0082] Thereafter, the MCU 33 (control unit 23) determines whether the communication battery 26 has been replaced (Battery changed?, step S44). If the communication battery 26 has been replaced (yes in step S44), after the replacement of the communication battery 26 is completed (Battery changed, step S46), the flow measurement device 30 continues the operation of wirelessly connecting with the base station and transitioning to standby mode (return to step S34). On the other hand, if the communication battery 26 has not been replaced (no in step S44), the power supply by the communication battery 26 ends and monitoring of the battery voltage ends (Battery dead, step S45). This ends the battery voltage monitoring method by the flow measurement device 30 according to the third embodiment.

[0083] As described above, in the flow rate measurement device 30 (battery voltage monitoring device) according to the third embodiment, the control unit 13 stores the first notification time, which is the time when the first alarm is generated, and the second notification time, which is the time when the second alarm is generated, in the storage unit 14, and calculates the remaining time T est is generated as notification information.

[0084] As a result, the control unit 13 can grasp the behavior of the decrease in the applied voltage (battery voltage) monitored by the load voltage monitoring unit 12 during the period from the first notification time to the second notification time, and approximate it to, for example, a linear function. This makes it possible to predict the time until the communication battery 26 is replaced by extrapolation. Therefore, not only can the warning information about the remaining capacity of the communication battery 26 or the warning information urging the replacement of the communication battery 26 be displayed, but also the remaining time T until the communication battery 26 is replaced can be displayed. est can also be generated as alarm information and notified by the notification unit 15.

[0085] (Embodiment 4) In this embodiment 4, in the battery voltage monitoring method executed by the flow measurement device 30 according to the embodiment 3, after the second alarm is issued (i.e., after the second alarm information is generated), the second alarm threshold Vth2 is updated based on the monitoring result of the load voltage monitoring unit 12, and alarm information with a higher degree of urgency (third alarm information) is generated as the alarm information. A typical example of this configuration will be specifically described with reference to Figures 10 and 11.

[0086] In the third embodiment, the decrease in battery voltage after the first notification threshold Vth1 is approximated to a linear function change (see FIG. 8). However, as the battery life of the communication battery 26 approaches its end, the decrease in battery voltage tends to accelerate. Therefore, as shown in FIGS. 10A and 10B, particularly in period 2 after the second notification threshold Vth2, the second notification threshold Vth2 is updated based on the applied voltage (battery voltage) monitored by the load voltage monitoring unit 12. This allows the slope of the battery voltage decrease to be reproduced more accurately, and the remaining time T est can be made more predictable.

[0087] For example, in Fig. 10A, similar to Fig. 8 described in embodiment 3, period 1 is set as the time period during which the battery voltage reaches from the first notification threshold Vth1 to the second notification threshold Vth2, and period 2 is set as the time period during which the battery voltage reaches from the second notification threshold Vth2 to the minimum guaranteed voltage Vmin. Here, during period 2 enclosed by the dashed dotted line in Fig. 10A, as shown in Fig. 10B, when the battery voltage decreases, the slope of the downward sloping straight line that approximates this gradually becomes steeper.

[0088] For example, Figure 10(b) illustrates the second notification threshold Vth2' corresponding to timing t2 and the second notification threshold Vth2' corresponding to the subsequent timing t2', and further illustrates a line L2 that approximates the second notification threshold Vth2 and a line L2' that approximates the second notification threshold Vth2'. The slope of the line L2' is clearly steeper than the slope of the line L2.

[0089] Therefore, in the fourth embodiment, the control unit 13 changes and overwrites (updates) the second notification threshold value from Vth2 to Vth2' based on the applied voltage, which is the monitoring result of the load voltage monitoring unit 12. This makes it possible to grasp the gradient of the actual battery voltage decrease, and therefore, for example, the remaining time T based on the formulas (1) and (2) exemplified in the third embodiment. est The accuracy of the extrapolation calculation can be further improved.

[0090] Furthermore, by overwriting the setting value of the second notification threshold in this manner, the setting value of the second notification threshold can be brought closer to the minimum guaranteed voltage Vmin, which makes it possible to generate, as notification information, for example, warning information indicating that the battery life of the communication battery 26 has reached its limit, such as final warning information.

[0091] An example of a battery voltage monitoring method configured in this manner will be described with reference to Figure 11 in addition to Figure 10. Note that the battery voltage monitoring method in this fourth embodiment is configured by adding a step of updating the second notification threshold Vth2 and a step of generating and notifying final alarm information to the battery voltage monitoring method described in the third embodiment (see Figure 9), but as with the third embodiment, the battery voltage monitoring method according to the present disclosure is not limited to this.

[0092] The steps from step S51 to step S63 in the battery voltage monitoring method shown in FIG. 11, i.e., the remaining time T est is generated as notification information and output to the notification unit 15 (step S62), and the notification unit 15 notifies the remaining time T est The steps up to notifying the user of this (step S63) are substantially the same as steps S31 to S43 in the battery voltage monitoring method shown in FIG. 9, and therefore a description thereof will be omitted.

[0093] The remaining time T estAfter the notification is generated and notified to the user, the MCU 33 (controller 23, see FIGS. 5 and 6) determines whether the communication battery 26 has been replaced (Battery changed?, step S64). If the communication battery 26 has been replaced (yes in step S64), the replacement of the communication battery 26 is completed (Battery changed, step S70), and then the flow measurement device 30 continues the wireless connection with the base station and the operation of transitioning to the standby mode (return to step S54).

[0094] On the other hand, if the communication battery 26 is not replaced (no in step S64), the MCU 33 (control unit 23) rewrites the second notification threshold Vth2 to a new threshold Vth2' (Overwrite Vth2 <- Vth2', step S65), and compares this new threshold Vth2' with the minimum guaranteed voltage Vmin (Vth2' < Vmin, step S66).

[0095] If it is not determined that the new threshold Vth2' has fallen below the minimum guaranteed voltage Vmin (no in step S66), the flow measurement device 30 continues the wireless connection with the base station and the transition operation to the standby mode (return to step S58). On the other hand, if it is determined that the new threshold Vth2' has fallen below the minimum guaranteed voltage Vmin (yes in step S66), the MCU 33 (controller 23) generates final alarm information as alarm information and outputs it to the alarm unit 25 (see FIG. 5), and the alarm unit 25 issues a final alarm based on this final alarm information (Send final alarm, step S67).

[0096] Further thereafter, the MCU 33 (control unit 23) determines whether the communication battery 26 has been replaced (Battery changed?, step S68). If the communication battery 26 has been replaced (yes in step S68), after the replacement of the communication battery 26 is completed (Battery changed, step S70), the flow measurement device 30 continues the operation of wirelessly connecting with the base station and transitioning to standby mode (return to step S34). On the other hand, if the communication battery 26 has not been replaced (no in step S68), the power supply by the communication battery 26 ends and monitoring of the battery voltage ends (Battery dead, step S69). This ends the battery voltage monitoring method by the flow measurement device 30 according to the third embodiment.

[0097] In this way, in the flow measurement device 30 (battery voltage monitoring device) according to the fourth embodiment, the control unit 13 further updates the setting value of the second notification threshold to a smaller value based on the applied voltage, which is the monitoring result of the load voltage monitoring unit 12, after generating the second alarm information. This makes it possible to change the second notification threshold in accordance with the decreasing behavior of the applied voltage, rather than setting the second notification threshold to a constant value. This further improves the accuracy of the remaining time prediction.

[0098] Furthermore, in the flow measurement device 30 (battery voltage monitoring device) according to the fourth embodiment, if the communication battery 26 is not replaced after the remaining time is notified, the control unit 13 compares the updated setting value of the second notification threshold with the minimum guaranteed voltage, and if it determines that this setting value has dropped below the minimum guaranteed voltage, generates third alarm information, such as final alarm information, which is information with a higher degree of urgency than the first alarm information or the second alarm information. In this way, by generating final alarm information based on the minimum guaranteed voltage, it is possible to notify the user as alarm information that the battery life has reached its limit.

[0099] In this embodiment, the third alarm information, which has a higher degree of urgency, is designated as the "final alarm information" as described above, but the present disclosure is not limited to this. For example, instead of designating the third alarm information as the "final alarm information," the third alarm information may be notified as a more significant "alarm" than the first or second alarm information, and then the "final alarm information" may be notified. Alternatively, the third alarm information may be followed by fourth alarm information, fifth alarm information, etc.

[0100] (Additional Notes) Based on the above description of the embodiments, the present specification discloses the following technologies: (Technology 1) A battery voltage monitoring device comprising a battery voltage monitoring unit that monitors the terminal voltage of a battery, a load voltage monitoring unit that monitors the applied voltage supplied from the battery to a power load, and a control unit, wherein the control unit generates first alarm information as alarm information when it determines that the terminal voltage monitored by the battery voltage monitoring unit has dropped below a predetermined first alarm threshold, and generates second alarm information as alarm information when it determines that the applied voltage monitored by the load voltage monitoring unit has dropped below a second alarm threshold that is lower than the first alarm threshold and higher than a minimum guaranteed voltage that is the lowest value of the applied voltage at which the power load can operate.

[0101] According to the above configuration, not only the terminal voltage of the battery serving as the power source is monitored, but also the voltage (applied voltage) supplied to the power load is monitored. A second notification threshold lower than the first notification threshold is set based on the lowest applied voltage at which the power load can operate. This allows battery depletion warning information to be generated based on not only the battery but also the power load. Therefore, even if the monitored value (measured value) of the battery terminal voltage does not adequately correspond to the operating voltage of the power load, the possibility of excessive battery depletion warnings can be effectively avoided or reduced.

[0102] Furthermore, with the above configuration, since both the voltage applied to the power load and the voltage of the battery are monitored, first alarm information can be generated based on a drop in the battery voltage, and second alarm information can be generated based on a drop in the voltage applied to the power load. This makes it possible to generate alarm information in two stages to notify the user of the battery-powered device that the remaining battery power is low. Therefore, for example, it is possible to change the weighting of the content of the alarm information between the first alarm information and the second alarm information.

[0103] (Technology 2) In the battery voltage monitoring device according to Technology 1, when the battery is replaceable, the control unit generates, as the second alarm information, information that prompts the user to replace the battery.

[0104] According to the above configuration, the second alarm information does not simply inform the user that the remaining battery power is low, but rather directly informs the user that a battery replacement is required. This makes it possible to generate notification information that not only informs the user of the remaining battery power but also the timing for battery replacement.

[0105] (Technology 3) In the battery voltage monitoring device described in Technology 1 or Technology 2, the control unit stores in the memory unit a first notification time, which is the time when the first alarm information is generated, and a second notification time, which is the time when the second alarm is generated, and generates notification information, which is the remaining time for which power can be supplied by the battery, using the first notification time and the second notification time.

[0106] According to the above configuration, the decreasing behavior of the applied voltage monitored by the load voltage monitoring unit can be grasped during the period from the first notification time to the second notification time. This makes it possible to predict the time until battery replacement by extrapolation. Therefore, it is possible to generate warning information not only about the remaining battery charge or warning information urging battery replacement, but also the remaining time until battery replacement.

[0107] (Technology 4) The battery voltage monitoring device according to Technology 3, wherein the control unit further updates the set value of the second notification threshold to a smaller value based on the applied voltage after generating the second alarm information.

[0108] According to the above configuration, the second notification threshold value can be changed according to the decreasing behavior of the applied voltage, rather than being set to a constant value, thereby further improving the accuracy of the remaining time prediction.

[0109] (Technology 5) In the battery voltage monitoring device described in Technology 4, if the battery is not replaced after the remaining time is notified, the control unit compares the updated setting value of the second notification threshold with the minimum guaranteed voltage, and if it determines that the setting value has dropped below the minimum guaranteed voltage, generates third alarm information as notification information, which is information with a higher degree of urgency than the first alarm information or the second alarm information.

[0110] According to the above configuration, third alarm information with a higher degree of urgency is generated based on the minimum guaranteed voltage, thereby making it possible to notify the user as notification information that the battery life is reaching its limit.

[0111] (Technology 6) A flow rate measurement device including the battery voltage monitoring device according to any one of technologies 1 to 5, a flow rate measurement unit that measures a flow rate of a fluid, and a notification unit that issues a notification based on the notification information.

[0112] According to the above configuration, the load voltage monitoring unit monitors the applied voltage of the battery that supplies power to the power load of the flow measurement device, and a second notification threshold can be set. This allows battery depletion in the flow measurement device to be generated as warning information based not only on the battery but also on the power load. This effectively avoids or reduces the possibility of issuing excessive warnings regarding battery depletion. Furthermore, the user of the flow measurement device can be notified of battery depletion in two stages: a first warning and a second warning. Therefore, for example, it is possible to change the weighting of the warning information for the first warning and the second warning.

[0113] (Technology 7) The flow rate measurement device according to Technology 6, further comprising a communication unit, wherein the power load is an RF circuit included in the communication unit.

[0114] According to the above configuration, the RF circuit of the communication unit of the flow measurement device is used as a power load, and the applied voltage of the battery that supplies power to the communication unit is monitored by the load voltage monitoring unit, and a second notification threshold can be set. This allows the flow measurement device to notify of the consumption of the communication battery in two stages: a first alarm and a second alarm. Furthermore, if the RF circuit is equipped with an A / D converter (ADC), this ADC can be used as the load voltage monitoring unit. Therefore, a battery voltage monitoring device can be realized as a functional configuration of the control unit of the flow measurement device without adding any new components.

[0115] (Technology 8) The flow rate measuring device according to Technology 6 or 7, which is a gas meter or a water meter.

[0116] It should be noted that the present disclosure is not limited to the description of the above-described embodiment, and various modifications are possible within the scope of the claims. Therefore, embodiments obtained by appropriately combining the technical means disclosed in different embodiments or multiple modifications are also included in the technical scope of the present disclosure.

[0117] Furthermore, many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof can be substantially changed without departing from the spirit of the present disclosure.

[0118] The present disclosure can be widely and suitably used in the field of monitoring the voltage of a battery provided in a battery-powered device, and in particular, when the battery-powered device is a flow measurement device such as a gas meter or a water meter, the present disclosure can be suitably used in the field of monitoring the voltage of a replaceable communication battery, for example.

[0119] 10: Battery voltage monitoring device 11, 21: Battery voltage monitoring section 12, 22: Load voltage monitoring section 13, 23: Control section 14, 24: Memory section 15, 25: Notification section 16: Power load battery 17: Power load 18: Battery installed in battery-operated device 20: MCU (control section) 26: Communication battery (battery for power load) 27: RF circuit (power load) 28: Antenna 29: Communication section 30: Flow rate measuring device 31: Flow rate measuring section 32: Flow rate measuring battery (battery installed in battery-operated device)

Claims

1. A battery voltage monitoring device comprising: a battery voltage monitoring unit that monitors the terminal voltage of a battery; a load voltage monitoring unit that monitors the applied voltage supplied from the battery to a power load; and a control unit, wherein the control unit generates first alarm information as alarm information when it determines that the terminal voltage monitored by the battery voltage monitoring unit has dropped below a predetermined first alarm threshold, and generates second alarm information as alarm information when it determines that the applied voltage monitored by the load voltage monitoring unit has dropped below a second alarm threshold that is lower than the first alarm threshold and higher than a minimum guaranteed voltage that is the lowest value of applied voltage at which the power load can operate.

2. The battery voltage monitoring device according to claim 1, wherein, if the battery is replaceable, the control unit generates, as the second alarm information, information urging the user to replace the battery.

3. The battery voltage monitoring device of claim 1, wherein the control unit stores in the memory unit a first notification time, which is the time when the first alarm information is generated, and a second notification time, which is the time when the second alarm is generated, and uses the first notification time and the second notification time to generate notification information indicating the remaining time for which power can be supplied by the battery.

4. The battery voltage monitoring device according to claim 3, wherein the control unit further updates the set value of the second notification threshold to a smaller value based on the applied voltage after the second alarm information is generated.

5. The battery voltage monitoring device of claim 4, wherein the control unit, if the battery is not replaced after the remaining time is notified, compares the updated setting value of the second notification threshold with the minimum guaranteed voltage, and if it determines that the setting value has dropped below the minimum guaranteed voltage, generates third alarm information as notification information, which is information with a higher degree of urgency than the first alarm information or the second alarm information.

6. A flow rate measuring device comprising: a battery voltage monitoring device according to any one of claims 1 to 5; a flow rate measuring unit that measures the flow rate of a fluid; and a notification unit that issues a notification based on the notification information.

7. The flow rate measuring device according to claim 6, further comprising a communication unit, wherein the power load is an RF circuit included in the communication unit.

8. The flow rate measuring device according to claim 6, which is a gas meter or a water meter.

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