JP4445949B2 - Voltage monitoring system and method - Google Patents

Description

  The present invention relates to a voltage monitoring system and method for monitoring a voltage of a power supply included in a communication system.

  Conventionally, there has been proposed an electric field communication system in which an electric field is induced in an electric field transmission medium such as a human body and various information communication is performed via the induced electric field. This electric field communication system has electric field communication devices equipped with transmission means and / or reception means, and is similar to other people and facilities (PCs, station ticket gates, vending machines, doors, gates, etc.) Owns or installs the electric field communication device, and performs information communication according to the purpose. This information communication makes it possible to collect data such as security authentication, billing, and location.

  These electric field communication devices have many applications that are carried by humans, and for this reason, the supply of electric power necessary for the operation of the electric field communication devices occupies most of the power supply configuration that relies on batteries. When a battery is used as a power source, there is a property that the voltage value at the start of use decreases with the passage of use time, regardless of the type of primary battery or secondary battery. About such a decrease in voltage value, although a design that is expected to some extent is performed in the electric field communication device, the battery voltage decrease is notified to the user etc. before it falls below the predetermined value necessary for normal operation, battery replacement and It is necessary to encourage charging.

  In order to inform the battery voltage drop, for example, conventionally, a light-emitting element such as an LED is provided in the electric field communication device, and flashing light emission is performed before the battery voltage falls below a predetermined value to alert the user. .

In addition, in order to notify that the battery voltage of the radio paging receiver using the battery as a power source has dropped, the battery voltage is monitored to detect a drop in the battery voltage, and the comparison result between the first and second threshold values There is also known a technique for performing a corresponding operation according to the above. When the battery voltage falls below the first threshold, the sounding and displaying of the sounder at regular intervals is repeatedly executed. When the battery voltage falls below the second threshold, the sounding and displaying of the sounder is stopped. Enter standby mode. The standby mode at the second threshold prevents a sudden battery voltage drop (see Patent Document 1).
Japanese Patent No. 3118514

  However, in the conventional technique for monitoring the voltage as described above, for example, when an operation of repeating blinking by an LED or sounding and displaying of a sounder is performed in a state where the battery voltage is lowered, it is necessary to execute this operation. Since a large amount of power is also supplied from the battery, the battery voltage drop was accelerated.

  The present invention has been made in view of the above, and an object of the present invention is to detect a decrease in the voltage of a battery or the like, and to switch to an operation with lower power consumption than usual, and to reduce the voltage without consuming power. It is to inform the decline.

  To achieve the above object, the present invention according to claim 1 is a voltage monitoring system for monitoring a voltage of a power source required for operation of an electric field communication means for inducing communication in an electric field transmission medium. A voltage drop detection means for comparing the voltage with a preset detection voltage to detect that the voltage has become equal to or lower than the detection voltage; and according to a detection result of the voltage drop detection means, Communication interval expansion means for expanding the interval to a preset multiple.

  Further, the present invention of claim 2 is the method according to claim 1, wherein a plurality of voltage values are preset for the detection voltage, and a multiple corresponding to each of the plurality of voltage values is set for the multiple. Yes.

  According to a third aspect of the present invention, in the first or second aspect, the communication is executed by repeating a predetermined number of times when the detection result is higher than the detection voltage. When the result is equal to or lower than the detection voltage, it is repeatedly executed by the number of times calculated by a coefficient set in advance to the number of times.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, a plurality of coefficients are set in advance as the coefficient calculated for the number of repetitions of the communication, and are set with the plurality of voltage values. A coefficient corresponding to each of the detection voltages is selected from the plurality of coefficients.

  Further, according to a fifth aspect of the present invention, in any one of the first to fourth aspects, the communication is polling communication.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the communication includes data, and comprises data protection means for storing the data and protecting the data.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the voltage drop detecting means detects that the voltage of the power source has dropped to a preset voltage lower than the detected voltage. In this case, communication stop means for stopping the communication is provided.

  Further, according to an eighth aspect of the present invention, in the sixth or seventh aspect, voltage drop information indicating a voltage drop is inserted into the data when the voltage drop detection unit detects a voltage equal to or lower than the detection voltage. .

  According to a ninth aspect of the present invention, there is provided a voltage monitoring method for monitoring a voltage of a power source required for operation of an electric field communication unit that performs communication by inducing an electric field in an electric field transmission medium. Comparing the voltage with a preset detection voltage to detect that the voltage has become equal to or lower than the detection voltage; and a communication interval expansion unit, wherein the communication interval is expanded according to the detection result of the voltage drop detection unit. Expanding the interval to a preset multiple.

  According to the present invention, it is possible to detect a voltage drop of a battery or the like, switch to an operation with lower power consumption than usual, and notify the voltage drop without consuming power.

<First Embodiment>
FIG. 1 is a block diagram for explaining a configuration according to an embodiment of a voltage monitoring system. FIG. 1 shows a main control unit 1 for controlling the overall operation, a power supply voltage monitoring (detection) unit 2, a monitoring voltage management (level setting) unit 3, and a CPU activation timing (CR timer) setting unit. 4, a transmission count management (setting) unit 5, a reception waiting time management (setting) unit 6, a reception control unit 7, a transmission control unit 8, a transmission / reception signal (modulation / demodulation) control unit 9, and a reception circuit The unit 10 and the transmission circuit unit 11 are shown.

  In such a configuration, the main control unit 1 is configured by a logical operation element such as a microcomputer, and performs arithmetic processing by a computer program set in advance based on input data. The operation of the voltage monitoring system is controlled by this arithmetic processing.

  The data input to the main control unit 1 is a detection value of the battery (power supply) voltage input from the power supply voltage monitoring unit 2, and the reference voltage for detection is set by the monitoring voltage management unit 3. It has been broken. The main control unit 1 also receives start-up timing data from the CPU start-up timing setting unit 4, and controls the start-up timing of a CPU (not shown) that performs electric field communication by the electric field communication device in accordance with this timing data. The The time data for the activation timing can be generated using an existing timer circuit such as a CR timer.

  The main control unit 1 controls, for example, an operation related to transmission / reception of an electric field communication system (electric field communication transceiver) to which the voltage monitoring system is applied based on a detection value from the power supply voltage monitoring unit 2. For this control, a reception waiting time management (setting) unit 6 and a transmission frequency management (setting) unit 5 are connected to the main control unit 1. With this configuration, the main control unit 1 performs operation control of the number of transmissions / receptions by the reception control unit 7 and the transmission control unit 8.

  The transmission / reception signal control unit 9 controls modulation and demodulation of signals necessary for transmission and reception. The receiving circuit unit 10 and the transmitting circuit unit 11 are circuits for inducing an electric field in an electric field voltage medium when electric field communication is performed or for receiving an electric field.

  FIG. 2 is a flowchart for explaining the operation according to the embodiment of the voltage monitoring system. In the flowchart of FIG. 2, when monitoring of the power supply voltage of the battery or the like is started, it is detected whether or not the voltage has decreased to a preset voltage value (S1). This voltage detection is performed by the power supply voltage monitoring unit 2, and the voltage value to be detected is set according to a value input and set in advance in the monitoring voltage management unit 3.

  Next, when a voltage drop is detected by voltage monitoring, a setting change of the number of transmissions is executed (S2). For example, when a control command from the main control unit 1 is input to the transmission count management unit 5, for example, a setting change of the transmission count in a polling operation is executed.

  Next, the reception waiting time setting change is executed (S3). This is done by inputting a control command from the main control unit 1 to the reception waiting time management unit 6 to change the setting of the reception waiting time.

  Next, the CPU start timing setting is changed (S4). Data to be communicated using the electric field communication device is generated, or the setting of the timing at which a CPU (not shown) for processing the received data is activated is changed.

  In the voltage drop detection processing step S1, if a voltage drop is detected (Yes), the processing from steps S2 to S4 is executed, and the process returns to the voltage drop detection processing step S1 again. When the voltage drop is still continued at the return of this processing, the state is maintained without repeating the operations of the processing steps S2 to S4. If the voltage drop is not detected (No), the voltage monitoring is continued until a voltage drop is detected.

  FIG. 3 is a table showing an example of setting values in each of the processing steps S1 to S4 in the flowchart shown in FIG.

  In the table shown in FIG. 3, in the processing step S1, the monitoring voltage is “a” when it is normal, and the voltage that is judged to be lower is the voltage that is less than “a”. When a voltage drop is detected in processing step S1, b / 2 is set where the number of transmissions is b in normal times in processing step S2. Similarly, in the processing step S3 at the time of voltage drop, the reception waiting time which is c at normal time is set to c / 2. In processing step S4, the CPU activation timing, which is d in normal times, is set to d × 2.

  By performing such setting when the voltage drops, the user using the electric field communication apparatus feels that the operation of the electric field communication apparatus is delayed and the time required for data communication is increased as a perceived phenomenon. By sensing such a change, the user can appropriately take measures such as battery replacement or recharging.

  In addition, as the operation to inform the user of the battery voltage drop when the voltage drops, all the operations are contents that further reduce the power consumption, so the voltage is surely given to the user without generating new power consumption. Can inform the decline.

<Second Embodiment>
FIG. 4 shows a timing chart for explaining a specific example of the first embodiment as the second embodiment.

  The timing chart shown in FIG. 4 shows the timings (T2) to (TC5) of the transmission timings on the same time axis for the transmission timings of polling that occur at intervals (T1) among the timings (TC1). (TC1) is the transmission processing timing, (TC2) is the transmission timing during the transmission processing of (TC1), (TC3) is the timing generated by the CR timer, and (TC4) is the UART (Universal Asynchronous Receiver) Transmitter) and timing related to mutual conversion between the parallel signal and the serial signal, and (TC5) shows the start timing of the CPU. FIG. 4 shows an example in which (T1) is set to 500 ms and (T2) is set to 100 μs for explanation. In the voltage monitoring system shown in FIG. 1, a mode for notifying the user of a voltage drop when a battery (power supply) voltage drop is detected will be described below.

  The transmission circuit unit 11 illustrated in FIG. 1 periodically performs transmission processing for ID transmission when activated in the transmission mode. This ID transmission is a mutual recognition means necessary for establishing and maintaining communication with the receiving side. The timing of the transmission process for the ID transmission is the timing shown in (TC1), and the ID transmission process is repeatedly performed at intervals (T1).

  Further, (TC2) shows the transmission timing by the transmission process, and ID transmission is executed five times at a time interval of (T2) as a transmission interval. That is, in one transmission process executed at an interval of (T1) at the timing of (TC1), 5 frames (Frame1 to Frame5) are transmitted at an interval of (T2) during the transmission process.

  Note that the CR timer generates the reference times (T1) and (T2) at the timing (TC3), and the UART operation for signal conversion is also intermittent as shown in (TC4). Further, with respect to the operation of the CPU that performs data communication via the electric field communication system, as shown in (TC5), the interval of (T1) is adjusted and the number of frames is adjusted, and the timing of (T1) is By stopping the CPU, the average transmission amount of data is reduced and the CPU load is reduced.

  Next, FIGS. 5 and 6 are flowcharts showing the operation according to the timing chart shown in FIG.

  In FIG. 5, a timer interrupt is started upon detection of a voltage drop (S10). This timer interrupt stops the timing (T1) count (S11). Next, transmission protocol processing is executed (S12).

  This transmission protocol process is executed according to the flowchart shown in FIG. Here, as shown in FIG. 6, first, frame transmission processing is started (S110). Next, UART initialization is executed (S111). Next, the number of frames (i) is set to i = 0 (S112).

  Next, it is determined whether or not the number of transmission frames is i = 5. When i = 5 (Yes) and transmission is completed in five frames as shown in (TC2), UART is stopped (S122). Next, the frame transmission process ends (S123).

  On the other hand, in process step S113, process steps S114 to S121 are repeatedly executed until i = 5.

  First, the frame signal becomes Enable (available) (S114). Next, Wait before transmission (standby) is executed for (T3) time (S115). Thereafter, a transmission process is executed (S116), a post-transmission wait after the transmission is completed (T4), and the frame signal is disabled (unusable) after a lapse of time (S117) (S118).

  Next, reactance is set (S119), and a time interval of (T2) is provided as an inter-frame wait to wait for the next transmission. Then, the value of the number of frames i is incremented (increased) (S121), and the determination of the number of frames is continued in the processing step (S113) again.

  Note that the data included in the frame signal is not limited to the ID and may be transmitted by including arbitrary data. In this case, a voltage drop identification bit (flag) for identifying a voltage drop may be provided in the frame signal. By detecting this flag on the receiving device side (not shown), it is possible to grasp that the battery voltage drop on the transmitting side has occurred. Based on this understanding, for example, data protection can be provided in case the data being received on the receiving side is interrupted.

  For data protection in response to such a voltage drop, in addition to providing a flag in the frame signal to perform data protection on the reception side, for example, data protection is also performed on data transmitted on the transmission side. For data that has not been transmitted or is being transmitted, non-volatile data storage means that does not require a power source for storing data may be provided to cope with an unintended voltage drop or disappearance of the power source (0 volts).

  Furthermore, when the voltage drops to a preset voltage, the communication processing is intentionally stopped to stop data transmission (communication stop means), and data corruption caused by unintentional transmission stop during data transmission It may be prevented beforehand.

  In any case, the transmission data may be temporarily stored in a storage unit such as a memory, and the stored data may be read and transmitted. By providing such a data buffer, even if data transmission is interrupted unintentionally, the original data is stored and protected in the storage means, so that data corruption can be prevented.

<Third Embodiment>
7 and FIG. 8 show more control value change in n steps (n is an arbitrary integer) than the two-step control value change configuration shown in FIGS. 2 and 3 in the first embodiment. FIG. 5 shows a flow chart and an example of set values for explaining an example of the third embodiment.

  First, the flowchart shown in FIG. 7 executes the same processing as the flowchart shown in FIG. The processing steps include S20 to S23. In each of the processing steps, a normal setting value and a setting value when a voltage drop is detected are set in four stages for each processing step. Here, for convenience of explanation, four levels of setting values are shown, but n levels of setting values other than the four levels may be set as necessary.

  In the setting values shown in FIG. 8, the value of the monitoring voltage in the processing step S20 is set in four stages of (1) to (4), where the normal time is a and the lower time is lower (1) to (4). That is, 0.9 × a for decrease (1), 0.85 × a for decrease (2), 0.82 × a for decrease (3), and 0.8 × a for decrease (4).

  Similarly, the number of transmissions of the processing step S21 is 0.9 × b for the decrease (1), 0.8 × b for the decrease (2), 0.6 × b for the decrease (3), and 0 for the decrease (4). .4 × b.

  Similarly, the reception waiting time in the processing step S22 is 0.9 × c for the decrease (1), 0.8 × c for the decrease (2), 0.6 × c for the decrease (3), and 0.6 × c for the decrease (4). 0.4 × c.

  Further, the CPU activation timing of processing step S23 is 1.5 × d for the decrease (1), 2.0 × d for the decrease (2), 3.0 × d for the decrease (3), and 5 for the decrease (4). 0.0 × d.

  Note that the value of the drop voltage to be monitored can be arbitrarily set, and may be determined in consideration of, for example, the battery voltage drop characteristic shown in FIG. When the voltage drop characteristic of the battery gradually decreases with the passage of time as shown by the solid line in FIG. 9, it is effective to set a plurality of set values for each voltage drop value as shown in FIG. Fine power control according to the reduced voltage and stepwise voltage drop notification to the user are possible. In the case of a battery having a characteristic in which a voltage drop suddenly occurs from a certain elapsed time as shown by a dotted line B or a chain line C in FIG. 9, the two-stage setting values shown in FIG. 3 are preferable.

  In addition, the voltage monitoring system according to the present embodiment is particularly an electric field communication system (electric field is induced in an electric field transmission medium via an electric field transmission medium such as a human body, and data transmission is performed using the induced electric field. On the other hand, it is suitable for power supply monitoring of an electric field communication transceiver used in a communication system that receives data by receiving an electric field) and its transmitter and receiver. These electric field communication transceivers mainly use a battery as a power source, and are effective in not only detecting a voltage drop of the battery and protecting data of data communication but also notifying the user of the voltage drop.

  According to the embodiment described above, it is possible to detect a voltage drop of a battery or the like, switch to an operation with lower power consumption than usual, and notify the voltage drop without consuming power.

The block diagram for demonstrating the structure which concerns on 1st Embodiment of a voltage monitoring system is shown. The flowchart for demonstrating the operation | movement which concerns on 1st Embodiment of a voltage monitoring system is shown. In the flowchart shown in FIG. 2, an example of setting values in each of the processing steps S1 to S4 is shown. The timing chart for demonstrating the specific example about 1st Embodiment as 2nd Embodiment is shown. The operation according to the timing chart shown in FIG. 4 is shown in the flowchart. The operation according to the timing chart shown in FIG. 4 is shown in the flowchart. The flowchart for demonstrating an example of the control numerical value change of n (n is arbitrary integers) steps as 3rd Embodiment is shown. An example of a control value change in n (n is an arbitrary integer) level is shown as a setting value for explaining the third embodiment. An example of the drop characteristic of a battery voltage is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main control part 2 ... Power supply voltage monitoring (detection) part 3 ... Monitoring voltage management (level setting) part 4 ... CPU starting timing (CR timer) setting part 5 ... Transmission frequency management (setting) part 6 ... Reception waiting time management (Setting) unit 7 ... Reception control unit 8 ... Transmission control unit 9 ... Transmission / reception signal (modulation / demodulation) control unit 10 ... Reception circuit unit 11 ... Transmission circuit unit

Claims (9)

In the voltage monitoring system for monitoring the voltage of the power source required for the operation of the electric field communication means for inducing communication in the electric field transmission medium,
A voltage drop detection means for comparing the voltage with a preset detection voltage and detecting that the voltage is equal to or lower than the detection voltage;
A communication interval expansion means for expanding the communication interval to a preset multiple according to the detection result of the voltage drop detection means;
A voltage monitoring system comprising: The voltage monitoring system according to claim 1, wherein a plurality of voltage values are set in advance for the detection voltage, and a multiple corresponding to each of the plurality of voltage values is set for the multiple. The communication is executed by repeating a preset number of times when the detection result is higher than the detection voltage, and when the detection result is equal to or less than the detection voltage, the communication is performed with a coefficient set in advance. The voltage monitoring system according to claim 1, wherein the voltage monitoring system is repeatedly executed by a number of times. A plurality of coefficients are set in advance as the coefficients calculated for the number of communication repetitions, and a coefficient corresponding to each of the detected voltages set by the plurality of voltage values is selected from the plurality of coefficients. The voltage monitoring system according to claim 2 or 3. The voltage monitoring system according to claim 1, wherein the communication is polling communication. The communication includes data;
6. The voltage monitoring system according to claim 1, further comprising data protection means for storing the data and protecting the data. The communication stop means for stopping the communication when the voltage drop detection means detects that the voltage of the power supply has dropped to a preset voltage lower than the detection voltage. The voltage monitoring system in any one of 1-6. 8. The voltage monitoring system according to claim 6, wherein voltage drop information indicating a voltage drop is inserted into the data when the voltage drop detection means detects a voltage equal to or lower than the detection voltage. In the voltage monitoring method for monitoring the voltage of the power source required for the operation of the electric field communication means for inducing communication in the electric field transmission medium,
In the voltage drop detection means, comparing the voltage with a preset detection voltage and detecting that the voltage is equal to or lower than the detection voltage;
In the communication interval expansion means, the step of expanding the communication interval to a preset multiple according to the detection result of the voltage drop detection means;
A voltage monitoring method comprising:

Images