JP2005085193A - Radio sensor system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio sensor system which can obtain high accuracy environmental information by transmitting the measured values of sensor devices to a base station, calibrating the measured values, and correcting the converted physical quantities. <P>SOLUTION: The radio sensor system comprises radio sensors which are provided at a plurality of points and acquire and transmit measured values, corresponding to ambient environmental information by sensor devices and a data collection terminal which is provided in the base station and receives measured values from radio sensors and calculates and collects environmental information. Each radio sensor has a sensor for measuring environmental information based on the physical characteristics of the sensor device and a radio transmitting/receiving part for transmitting the measured values by radio, and the data collection terminal has a conversion information storage part wherein physical characteristics of sensor devices of registered radio sensors and conversion information for conversion from measurement values to environmental information are stored for each radio sensor and a conversion part for performing arithmetics, to convert measured values to environmental information by physical characteristics and conversion information corresponding to the radio sensors. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless sensor system in which a sensor notifies environmental information around an installation using a wireless communication device, and a base station collects environmental information from a plurality of sensors.

The conventional wireless sensor calculates the temperature from the resistance value (sensor measurement value) measured by the sensor device and measures the temperature (environment information) as the calculation result when measuring the environment information of the measurement target, for example, the temperature. (See Patent Document 1).
For this reason, since the conventional wireless sensor transmits to the base station after correcting environmental information (for example, temperature) in an individual sensor device, the numerical value of environmental information with high measurement accuracy can be obtained. .

Japanese Patent Laid-Open No. 02-138837

However, in the above conventional example, in the wireless sensor, the physical quantity (resistance value, voltage value, current value, pressure value, frequency value, etc.) that is the measured value of the sensor is converted into environmental information (temperature, humidity, snow cover, various types). Therefore, there is a problem that the calculation processing for conversion increases and the amount of power consumption increases.
Further, in this conventional example, the configuration of the wireless sensor is complicated and expensive because of the arithmetic processing for converting the physical quantity, which is the measurement value of the sensor, into the numerical value of the environmental information.

Further, in order to cope with the above problem, the measurement value measured by the sensor device is transmitted to the base station as it is, and the base station performs an operation for converting the physical quantity, which is the measurement value, into environmental information. The load is reduced and the configuration of the sensor device is simplified.
On the other hand, in this method, since there is only an arithmetic processing function corresponding to a specific sensor device, that is, a specific sensor device, it becomes a unique sensor system, which can be replaced with another type of sensor device or a plurality of types of sensor devices. However, there is a drawback that the system configuration is difficult.

In addition, the sensor system of the above method uses a uniform conversion table when using a look-up table method in an operation for converting a physical quantity as a measurement value into environmental information. It is difficult to create a system configuration with a device.
In addition, the sensor system of the above method only converts a physical quantity (raw data measured by the sensor), which is a sensor measurement value, into a numerical value of environmental information. Calibration of the measurement value and correction of the converted environmental information can be performed. It is not possible to cope with aging of individual sensor devices.

  The present invention has been made in view of such circumstances. The measurement value of the sensor device is transmitted to the base station, the measurement value is calibrated, and the converted physical quantity is corrected to obtain highly accurate environmental information. An object of the present invention is to provide a wireless sensor system that can be obtained.

  The wireless sensor system of the present invention is provided at a plurality of points, a wireless sensor that acquires and transmits measurement values corresponding to surrounding environmental information by a sensor device, and a measurement value from the wireless sensor provided at a base station. Is a wireless sensor system comprising a data collection terminal that collects environmental information from the measured value and collects environmental information of the point, and the wireless sensor converts the surrounding environmental information into the physical characteristics of the sensor device. A data output terminal comprising: a sensor that outputs as a measurement value based thereon; and a wireless transmission unit (wireless transmission / reception unit 2 and wireless transmission unit 2B) that wirelessly transmits measurement data including the measurement value and identification data. However, for each wireless sensor, a conversion information storage unit that stores conversion information for conversion from measured values of sensor devices of registered wireless sensors to environmental information; and Determining a wireless sensor from another data by the physical properties and conversion information corresponding to the wireless sensor, and having a conversion unit for performing an operation for converting the measured value to the environmental information.

  In the wireless sensor system of the present invention, the wireless sensor includes a storage unit, and physical characteristics and conversion information of the sensor device are stored. In the registration process for the data collection terminal, the wireless terminal Characteristic and conversion information are transmitted to the data collection terminal, and the data collection terminal stores the physical characteristic and conversion information in the conversion information storage unit corresponding to the identification number of the wireless sensor.

  The wireless sensor system of the present invention is characterized in that the conversion information includes an initial deviation of physical characteristics and correction information of physical characteristics.

  In the wireless sensor system of the present invention, a calibration coefficient is stored as aging data of the physical characteristics obtained statistically for the sensor device used by the wireless sensor, and at the time of registration, a calibration cycle, The calibration coefficient is transmitted to the data collection terminal.

  In the wireless sensor system of the present invention, the output voltage of the battery to which the wireless sensor supplies driving power is measured at a constant cycle, and when the output voltage becomes a predetermined voltage value or less, a request signal for requesting battery replacement is sent to the data. It transmits to a collection terminal, It is characterized by the above-mentioned.

As described above, according to the wireless sensor system of the present invention, in the measurement wireless sensor installed at the point where environmental information is measured, the numerical value of the environmental information is calculated from the physical quantity that is the measured value measured by the sensor device. Therefore, since the configuration of the wireless sensor can be simplified and generalized, a mass production effect can be expected and the manufacturing cost can be reduced.
Further, according to the wireless sensor system of the present invention, the data collection terminal calculates the environmental information from the measurement value transmitted from the wireless sensor, so it is possible to cope with a plurality of types of environmental information, and various sensor devices. It is possible to construct a system corresponding to the above, and it is possible to improve the accuracy of environmental analysis of a point to be measured from a plurality of types of environmental information.

Furthermore, according to the wireless sensor system of the present invention, at the time of registration, the physical characteristics and conversion information of the sensor device in the wireless sensor are registered in the conversion information storage unit corresponding to the identification number of the wireless sensor, and this conversion is performed. Based on the information stored in the information section, the environment information is calculated from the measured value, so that the wireless sensor can be easily added to the system.
In addition, according to the wireless sensor system of the present invention, the configuration coefficient constituting the measurement value is registered in the conversion information storage unit at the time of registration, and the measurement value can be calibrated by this configuration coefficient, Since correction information is also stored, it is possible to easily correct the numerical values of the converted environmental information, and to obtain highly accurate environmental information.

  Hereinafter, a wireless sensor system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of the embodiment. In this figure, a wireless sensor 1 is provided at a plurality of points, and a wireless transmission / reception unit 2 that wirelessly transmits measured values together with identification numbers as measurement data, environmental information such as temperature, humidity, volume, and various gas concentrations. Sensor device 3 for measuring a physical quantity corresponding to the measurement value, a storage unit 4 for storing the type of sensor device 3, physical characteristics, initial value deviation, conversion information such as correction information of physical characteristics, and identification number of the wireless sensor doing. Here, if the sensor device 3 performs temperature measurement using a resistance value (for example, a thermistor) that is a physical quantity as a measurement value, the sensor device 3 indicates a temperature change as environmental information, and a temperature characteristic of the sensor. Therefore, the temperature as the environmental information is calculated from the resistance value that changes corresponding to this temperature.

For this reason, the type of sensor device 3 is a resistance value, and the physical characteristic may be a general expression indicating the relationship between temperature and resistance value (a lookup table indicating the relationship between resistance value and temperature may be used. The initial value deviation is a deviation (deviation) from the above general formula at, for example, 25 ° C., and the correction information (change) for the numerical value of the predetermined temperature obtained by this general formula is the correction information of the physical characteristics. Deviation of straight line inclination, deviation of curvature of change curve, etc.).
Moreover, the calibration value of the sensor peripheral circuit which comprises a sensor device is also contained, such as when the assembly process of a sensor and the sensor device 3 differs. Thereby, individual management of the sensor and the sensor device 3 in the assembly process is possible, and efficient assembly management can be performed.
Further, the storage unit 4 stores a calibration coefficient for a physical quantity measured with the sensor device 3 over time (physical characteristics over time) as coefficient information for each time period (for example, 6 months, 1 year,...). Has been. The calibration coefficient is obtained by predicting the secular change of the sensor by statistical processing from the evaluation results of a plurality of similar sensors by an evaluation method such as aging.

  The base station 5 receives data such as measurement values transmitted by the wireless sensor 1 wirelessly, and transmits the data via the network 6 to a data collection terminal 7 that collects and analyzes environmental information. Here, the network 6 is an information communication network including a dedicated information communication line, a public information communication line, the Internet, and the like. The data collection terminal 7 is a conversion unit 8 that performs an operation of converting the measurement value into a numerical value of the environment information based on the conversion information, and a conversion that stores the conversion information and the calibration coefficient of the sensor device 3 in each wireless sensor 1 corresponding to the identification number. The information storage unit 9 and the data storage unit 10 that stores the numerical value of the environment information of each wireless sensor 1 and the installation location (measurement point) of the wireless sensor 1 for each identification number are provided.

  Next, the sensor device 3 of FIG. 1 will be described with reference to FIG. FIG. 2 is a block diagram showing a temperature sensor which is an example of the sensor device 3 of FIG. In this figure, since the oscillation frequency of the oscillator 3a is determined according to the resistance value of the thermistor 3b, the oscillation frequency changes corresponding to the temperature as the resistance value of the thermistor 3b changes due to temperature change. The counter 3c counts the pulses oscillated by the oscillator 3a, outputs the count value to the wireless transmission / reception unit 2 every predetermined period (for example, 30 minutes) and resets the count value to “0”. A new count value is counted in a predetermined period. That is, the sensor device 3 uses the temperature, which is environmental information, as a pulse count value (indicating an oscillation frequency) for a predetermined period indicating a resistance value (physical quantity) of a thermistor 3b (eg, NTC (Negative Temperature Coefficient) thermistor). Measurement is performed, and the count value, which is the measurement value, is output to the wireless transceiver 2. The oscillator 3a uses a Wien bridge circuit that is stable against voltage fluctuations and temperature fluctuations. As a result, even with respect to voltage fluctuations of the power supply, fluctuations in the resistance value of the thermistor 3b accompanying temperature changes can be obtained by the oscillation frequency, and stable temperature measurement can be performed.

Next, with reference to FIG. 1, the operation example of the wireless sensor system which is one Embodiment is demonstrated.
<Registration process of wireless sensor 1 to data collection terminal 7>
An example of registration processing of the wireless sensor 1 in the data collection terminal 7 in the wireless sensor system will be described with reference to FIG. FIG. 3 is a sequence diagram showing transmission / reception of each data through the base station 5 and the network 6 between the wireless sensor 1 and the data collection terminal 7. In the following description, the temperature sensor of FIG.

When the registration process of the wireless sensor 1 is performed, the wireless transmission / reception unit 2 of the wireless sensor 1 instructs the operation of the registration process. For example, when the start button of the registration process is pressed, the wireless transmission / reception unit 2 makes the data collection terminal of the wireless sensor 1 7 starts the registration processing operation.
The wireless transmission / reception unit 2 transmits a registration request signal including the address and identification number of the wireless sensor 1 to a predetermined data collection terminal 7 according to the address preset in the storage unit 4 (step S1). When the data collection terminal 7 determines that the received signal is a registration request signal, the data collection terminal 7 determines whether or not the included identification number is preset in the signal data storage unit 10 as being registerable. If the identification number is a registerable identification number, the data collection terminal 7 transmits an authentication confirmation signal indicating that the registration process is continued to the wireless sensor 1 using the address input together with the identification number. On the other hand, if the data collection terminal 7 is not an identifiable identification number, the data collection terminal 7 transmits an authentication confirmation signal indicating that the registration process is to be stopped to the wireless sensor 1 and stops the registration process (step S2).

Next, when the wireless transmission / reception unit 2 receives an authentication confirmation signal indicating that the registration process is to be continued, the wireless transmission / reception unit 2 reads the conversion information and the calibration coefficient stored in the storage unit 4. It transmits to the data collection terminal 7 with the identification number of the sensor 1 (step S3). The conversion information transmitted here is a relational expression between a count value (oscillation frequency) and a resistance value and a general expression between a resistance value (physical quantity) and temperature in a predetermined period output from the temperature sensor (sensor device 3) in FIG. , A deviation from this general formula at 25 ° C., a correction coefficient for a predetermined temperature obtained by this general formula, and the calibration coefficient is measured in the sensor device 3 every time period (for example, 6 months, 1 year,...). This is the calibration coefficient for the change over time of the physical quantity.
Then, the data collection terminal 7 stores the received conversion information and calibration information in the conversion information storage unit 9 corresponding to the simultaneously received identification number (step S4).

  Next, the data collection terminal 7 reads the conversion information and calibration information corresponding to the registered identification number of the wireless sensor 1 from the conversion information storage unit 9, adds a confirmation request, and uses the wireless sensor 1 as a conversion information confirmation signal. (Step S5). When the wireless sensor 1 receives the conversion information confirmation signal, the wireless sensor 1 reads the conversion information and calibration information from the storage unit 4, reads the conversion information and calibration information that has been read, and the conversion information and calibration added to the conversion information confirmation signal. The information is compared to determine whether or not they are the same, and if they are detected to be the same, a confirmation signal indicating that they are the same is transmitted to the data collection device 7. The process is returned to S3 (step S6). Next, when the data collection terminal 7 receives the confirmation signal indicating the same from the wireless sensor 1, the data collection terminal 7 detects that the conversion information and the calibration information are normally stored in the conversion information storage unit 9, and each information Is registered normally (step S7).

<Environmental information measurement process>
Next, with reference to FIG.1 and FIG.2, the operation example of the measurement process of the environmental information in the wireless sensor system by one Embodiment is demonstrated.
The wireless sensor 1 adds the identification number (measured value) output from the counter 3c every predetermined period, for example, every 30 minutes, and adds the identification number to the data collection terminal 7 by the wireless transmission / reception unit 2 as measurement data. Send to.
Next, when receiving the measurement data, the data collection terminal 7 determines whether or not the identification number is stored in the conversion information storage unit 9. When the identification number is detected in the conversion information storage unit 7, the data collection terminal 7 reads the conversion information and the calibration information corresponding to the identification number by the conversion unit 8.

Next, based on the read conversion information, for example, in the case of temperature, the conversion unit 8 obtains the resistance value of the thermistor 3b from the relational expression between the count value (that is, the oscillation frequency) and the resistance value. Then, the conversion unit 8 determines whether or not the elapsed time period during which the calibration information is calibrated is exceeded. If not, the conversion unit 8 sets the resistance value as it is. Multiply the value and use the multiplication result as a new resistance value. Next, the conversion unit 8 performs a calculation for obtaining the temperature by including the value of the initial value deviation as a correction value in the general formula indicating the relationship between the resistance value of the conversion information and the temperature. Then, the conversion unit 8 multiplies the correction coefficient set for each predetermined temperature by the numerical value of the temperature obtained from the general formula to perform a calculation for obtaining the temperature as final environmental information, and the calculation result Is stored in the data storage unit 10 together with the measurement date and time data in correspondence with the identification number.
Further, in the case of temperature, the conversion unit 8 may obtain the temperature directly from the count value by a general expression indicating the relationship between the count value and the temperature. At this time, has the time period over which calibration information is calibrated exceeded? A determination is made as to whether or not the temperature is not exceeded. If the temperature is exceeded, the calibration coefficient is multiplied by the temperature, and the multiplication result is set as a new temperature.

  Further, when transmitting the measurement data, the wireless sensor 1 may measure the output voltage of the battery that supplies the driving power, and transmit the measurement data along with the measurement data. Thereby, the data collection terminal 7 determines whether or not the output voltage is a numerical value lower than the set threshold value, and continues the process if it is determined that the output voltage is a numerical value exceeding the threshold value. When it is determined that the value is lower than the threshold value, information for instructing battery replacement is displayed on the display unit or the like.

  As another embodiment, in the wireless sensor 1 described above, the wireless transmission / reception unit 2 may be a wireless transmission unit 2B that performs only wireless transmission. In this case, when the registration request signal including the address and identification number of the wireless sensor 1 is transmitted to the data collection terminal 7 by the same process as in the embodiment at the time of the registration process, the data collection device 7 authenticates with the identification number.・ Do the registration process. Accordingly, since it is not necessary to provide a reception function, a wireless sensor with a smaller size and lower power consumption can be obtained. Other operations are the same as those in the embodiment.

  The environment information is recorded by recording a program for realizing the functions of the data processing terminal 7 in FIG. 1 on a computer-readable recording medium, causing the computer system to read and execute the program recorded on the recording medium. May be collected. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

It is a block diagram which shows the structural example of the wireless sensor system by one Embodiment of this invention. It is a block diagram which shows the structural example of the temperature sensor which is an example of the sensor device 3 in FIG. It is a sequence diagram which shows the flow of the registration process with respect to the data collection terminal 7 of the wireless sensor 1 of the wireless sensor system by one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless sensor 2 ... Wireless transmission / reception part 3 ... Sensor device 4 ... Memory | storage part 5 ... Base station 6 ... Network 7 ... Data collection terminal 8 ... Conversion part 9 ... Conversion information storage unit 10 ... Data storage unit

Claims (5)

A wireless sensor that is provided at a plurality of points and that acquires and transmits measurement values corresponding to the surrounding environment information by the sensor device, and a measurement value from the wireless sensor that is provided at the base station is received from this measurement value It is a wireless sensor system comprising a data collection terminal that calculates environmental information and collects environmental information of the point,
The wireless sensor is
A sensor that outputs ambient environmental information as a measured value based on the physical characteristics of the sensor device;
A wireless transmission unit that wirelessly transmits measurement data including the measurement value and identification data;
The data collection terminal is
For each wireless sensor, a conversion information storage unit that stores conversion information for conversion from measurement values of sensor devices of registered wireless sensors to environmental information;
A wireless sensor system comprising: a conversion unit that determines a wireless sensor from the identification data and performs an operation of converting the measurement value into environment information based on the physical characteristics and conversion information corresponding to the wireless sensor.   The wireless sensor has a storage unit, and physical characteristics and conversion information of the sensor device are stored. In the registration process for the data collection terminal, the wireless terminal collects the physical characteristics and conversion information in the data collection. The wireless sensor system according to claim 1, wherein the data collection terminal stores physical characteristics and conversion information in a conversion information storage unit corresponding to an identification number of the wireless sensor.   The wireless sensor system according to claim 1, wherein the conversion information includes an initial deviation of physical characteristics and correction information of physical characteristics.   For the sensor device used by the wireless sensor, a calibration coefficient is stored as aging data of statistically obtained physical characteristics, and at the time of registration, a calibration cycle and a calibration coefficient are stored in the data collection terminal. The wireless sensor system according to claim 1, wherein the wireless sensor system is transmitted to the wireless sensor system. The wireless sensor measures the output voltage of a battery that supplies driving power at a constant period, and transmits a request signal for requesting battery replacement to the data collection terminal when the output voltage falls below a predetermined voltage value. The wireless sensor system according to any one of claims 1 to 4.

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