JP6122770B2 - Sensor terminal - Google Patents

Description

  The present invention relates to a technology of a sensor terminal.

  There is a sensor network system that collects data from sensors and measuring devices installed at remote locations. Various services such as remote meter reading, vending machine inventory management, truck delivery management, greenhouse temperature monitoring, substation equipment monitoring, etc. for the purpose of improving business efficiency, improving serviceability, and ensuring safety and security Has been expanded.

  In recent years, with the growing awareness of energy conservation even in ordinary households, the use of sensor information such as current sensors, temperature sensors, humidity sensors, illuminance sensors, human sensors, etc. Demonstration experiments are being conducted. From the viewpoint of housing quality, it is also considered to measure environmental data around a house with a vibration sensor, an inclination sensor, an ultraviolet sensor, etc., and to utilize the house history information as value-added information on real estate.

  FIG. 6 is a diagram illustrating a configuration example of a sensor network system in a home. A sensor 2 is connected to the sensor terminal 1, and sensor data detected by the sensor 2 is collected by the base station 3 in the house and transferred to the server 6 outside the house via the router 4 and the optical line 5.

  For example, when utilizing environmental data, it is required to collect a plurality of sensor data. At that time, a method of installing many types of sensor terminals in the same place or a method of installing one sensor terminal equipped with a plurality of sensors can be considered. In terms of cost, the latter, which can share a communication module, is desirable.

  Sensor terminals equipped with a plurality of sensors, which are the latter, include a sensor built-in type and a sensor external type. Non-Patent Document 1 discloses a sensor terminal that incorporates a plurality of sensors in advance and is assumed to be developed for various uses. On the other hand, in the case of an external sensor type, various sensors are connected by a predetermined interface. Patent Document 1 discloses a remote monitoring system in which a plurality of sensors can be connected externally.

JP 2006-33441 A

“Wireless Eco Sensor”, Sugihara SEI Co., Ltd., [online], [searched on November 19, 2013], <URL: http://www.ssei.co.jp/seihin/uc_e100.html >

  However, in the sensor terminal incorporating a plurality of sensors, if the sensor specifications prepared in advance do not meet the requirements of the user, it is necessary to change the sensor itself and the peripheral circuit, modify the sensor terminal board, In some cases, it may be necessary to recreate it.

  In addition, when trying to realize a highly versatile system as in Patent Document 1, the circuit scale and the number of parts of the sensor input unit increase, and there is a concern that the part cost, manufacturing cost, quality control cost, and terminal size increase. . These are factors that hinder the spread of the sensor network system to ordinary households.

  Here, FIG. 7 shows a conventional example of an external sensor type sensor terminal. The sensor terminal 1 includes a terminal block 11, a signal adjustment circuit 12, a microcontroller 13, a memory 14, a communication module 15, and a power supply unit 16. As shown in FIG. 8, the signal adjustment circuit 12 includes a filter 12b, a rectifier circuit C, a changeover switch 12f, a plurality of load resistors R having different resistance values, and an amplifier 12g. The unit is provided for each sensor 2.

  The electric signal input from the sensor 2 is subjected to processing such as noise removal, rectification, smoothing, current-voltage conversion, signal amplification, and impedance matching by the signal adjustment circuit 12. At that time, the signal amplification factor is adjusted by switching the load resistance R. Thereafter, it is converted into a digital value by the A / D converter 13 a mounted on the microcontroller 13.

  The signal adjustment circuit 12 has an optimum configuration corresponding to the number of sensor connections according to the type (DC / AC, voltage / current) of the electric signal input from the sensor 2, and the plurality of unit configurations are mounted in parallel. The circuit scale and the number of parts of the sensor input unit increase in proportion to the number of sensors connected.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a sensor terminal that achieves both high versatility and economy.

The sensor terminal according to claim 1, a first selection circuit that selects one of a plurality of sensors, a plurality of signal adjustment circuits that respectively adjust an electric signal from the sensor according to a type of the electric signal, A second selection circuit that selects any one of the plurality of signal adjustment circuits and outputs an electrical signal from a sensor selected by the first selection circuit to the selected signal adjustment circuit; Based on the variable gain amplifier that amplifies the electric signal from the signal adjustment circuit selected by the selection circuit, and the corresponding data that associates the sensor, the type of the electric signal, and the gain value corresponding to the type of the sensor and the electric signal. A control unit that switches each selection destination of the first selection circuit and the second selection circuit and changes a gain value of the variable gain amplifier, and the plurality of signal adjustment circuits include Duplicate Share resistor in the signal conditioning circuit of the control unit, the the switching operation of the selection target by the first selection circuit, and the switching operation of the selection target by the second selection circuit, the gain The gist is to repeatedly execute the corresponding data while synchronizing the operation of changing the gain value in the variable amplifier.

  The sensor terminal according to claim 2 is the sensor terminal according to claim 1, wherein the first selection circuit is connected between the plurality of sensors and the second selection circuit. And

  The sensor terminal according to claim 3 is the sensor terminal according to claim 1, wherein the first selection circuit is connected between a power supply terminal and a power supply of the plurality of sensors. To do.

  According to the present invention, it is possible to provide a sensor terminal having both high versatility and economy.

It is a figure which shows the 1st structural example of a sensor terminal. It is a figure which shows the example of a setting table. It is a figure which shows the example of a setting message. It is a figure which shows the operation | movement flow of a sensor terminal. It is a figure which shows the 2nd structural example of a sensor terminal. It is a figure which shows the structural example of a sensor network system. It is a figure which shows the structure of the conventional sensor terminal. It is a figure which shows the structure of the conventional signal adjustment circuit.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration example of the sensor terminal 1 according to the first embodiment. The sensor terminal 1 has the same configuration as that of the conventional sensor terminal 1 shown in FIG. 7, but the configurations of the signal adjustment circuit 12 and the microcontroller 13 are changed.

  The signal adjustment circuit 12 includes a first selection circuit 12a, a filter 12b, a second selection circuit 12c, four signal adjustment circuits 12d1 to 12d4, and a variable amplifier 12e.

  The first selection circuit 12a is connected between the terminal block 11 and the filter 12b, selects any one of the plurality of sensors 2 connected to the terminal block 11, and filters the electrical signal from the selected sensor 2. To 12b.

  The filter 12b is connected between the first selection circuit 12a and the second selection circuit 12c, and removes a noise component from the electrical signal from the sensor 2 selected by the first selection circuit 12a.

  The second selection circuit 12c is connected between the filter 12b and the four signal adjustment circuits 12d1 to 12d4, selects one of the plurality of signal adjustment circuits 12d1 to 12d4, and is selected by the first selection circuit 12a. The selected electrical signal from the sensor 2 is output to the selected signal adjustment circuit 12d.

  The four signal adjustment circuits 12d1 to 12d4 are connected in parallel between the second selection circuit 12c and the variable amplifier 12e, and adjust the electric signal from the second selection circuit 12c according to the type of the electric signal. Specifically, it is composed of rectifier circuits C1 and C2 made of diodes, a load resistor R1, a voltage dividing resistor R2, and the like, and converts an inputted electric signal into an electric signal of a DC voltage.

  For example, the first signal adjustment circuit 12d1 is a circuit for converting an electric signal of an alternating current or an alternating voltage into a direct voltage, and a rectifier circuit C1 is connected between the second selection circuit 12c and the variable amplifier 12e. The load resistor R1 is connected between the output of the rectifier circuit C1 and the ground.

  The second signal adjustment circuit 12d2 is a circuit for converting an electric signal of a direct current or a direct current voltage into a direct current voltage, and directly connects the second selection circuit 12c and the variable amplifier 12e. A load resistor R1 is connected between the connection line and the ground.

  The third signal adjustment circuit 12d3 is a circuit for converting an electrical signal of an alternating voltage into a direct voltage, and the rectifier circuit C2 and the voltage dividing resistor R2 are interposed between the second selection circuit 12c and the variable amplifier 12e. Are connected in series, and a load resistor R1 is connected between the output of the voltage dividing resistor R2 and the ground.

  The fourth signal adjustment circuit 12d4 is a circuit for converting an electric signal of a DC voltage into a DC voltage. A voltage dividing resistor R2 is connected between the second selection circuit 12c and the variable amplifier 12e, A load resistor R1 is connected between the output of the voltage dividing resistor R2 and the ground.

  The variable amplifier 12e is connected between the four signal adjustment circuits 12d1 to 12d4 and the microcontroller 13, and amplifies the electric signal from the signal adjustment circuit 12d selected by the second selection circuit 12c. The gain value can be adjusted by rewriting the internal register.

  The above is the configuration of the signal adjustment circuit 12.

  Next, the microcontroller 13 will be described. The microcontroller 13 includes a storage unit 13b and a control unit 13c in addition to the A / D converter 13a illustrated in FIG.

  The storage unit 13b stores a setting table used when switching the selection destinations of the first selection circuit 12a and the second selection circuit 12c, respectively, and when changing the gain value of the variable amplifier 12e.

  An example of the setting table is shown in FIG. The setting table of this example associates the input terminal ID of the terminal block 11, the type of the electric signal from the sensor 2, and the gain values corresponding to the input terminals 11a to 11d of the terminal block 11 and the type of the electric signal. Each corresponding data. The input terminal ID is used when the selection destination is switched by the first selection circuit 12a, and the type of the electric signal is used when the selection destination is switched by the second selection circuit 12c.

  The data in the setting table may be written locally to the sensor terminal 1 using an arbitrary setting device, or may be written remotely by a setting message transmitted from the external server 6 (see FIG. 6). The setting message has a format (sensor terminal ID, command type, sensor channel, setting data) as shown in FIG. The setting data includes the type of electric signal (DC / AC, voltage / current) and gain information. Individual setting may be performed for each sensor channel using the setting message, or batch setting may be performed for each sensor terminal using a batch setting message as illustrated in FIG. Further, a plurality of necessary sensor channels may be selected and set using a setting message as shown in FIG.

  Using the setting table stored in the storage unit 13b, the control unit 13c switches each selection destination of the first selection circuit 12a and the second selection circuit 12c, and further changes the gain value of the variable amplifier 12e. . At that time, a control signal for instructing each control is used.

  The above is the configuration of the microcontroller 13.

  So far, the configuration of the sensor terminal 1 has been described. In this example, the maximum number of sensors 2 is four, but this is not a limitation. That is, the number of input terminals of the terminal block 11 and the number of selection destinations of the first selection circuit 12a may be five or more according to the type and number of the sensors 2, or may be limited to one. .

  Next, the operation of the sensor terminal 1 will be described. FIG. 4 is a diagram illustrating an operation flow of the sensor terminal 1. However, the clamp type AC current sensor 2a is connected to the first input terminal 11a of the terminal block 11, the voltage output type illuminance sensor 2b is connected to the second input terminal 11b, and the analog current is connected to the third input terminal 11c. It is assumed that the (4-20 mA) output sensor 2c is connected, and the analog voltage (1-5V) output sensor 2d is connected to the fourth input terminal 11d.

  First, the processing of the electrical signal from the clamp-type alternating current sensor 2a will be described.

  First, the control unit 13c in the microcontroller 13 selects the second selection circuit 12c based on the setting table acquired from the storage unit 13b so that the electric signal of the input alternating current is input to the rectifier circuit C1. Is switched to the first signal adjustment circuit 12d1 (step S1), and the register is set so that the gain of the variable amplifier 12e is 6 dB (step S2).

  Next, based on the setting table, the selection destination of the first selection circuit 12a is switched to the first input terminal 11a so that the electric signal from the clamp-type alternating current sensor 2a is input into the signal adjustment circuit 12 ( Step S3).

  The input electric signal is rectified by the rectifier circuit C1 after the high frequency component is removed by the filter 12b. The rectified direct current electric signal is converted into a voltage by the load resistor R1, and then amplified to a set level by the variable amplifier 12e.

  Thereafter, the converted and amplified DC voltage electrical signal is input to the microcontroller 13 and converted to a digital value by the A / D converter 13a. At this time, in order to suppress the influence of noise, the A / D converter 13a performs an averaging process after sampling the digital value a predetermined number of times (steps S4 to S6).

  Next, processing of electrical signals from the illuminance sensor 2b will be described.

  First, the control unit 13c in the microcontroller 13 selects the second selection circuit 12c based on the setting table acquired from the storage unit 13b so that the input DC voltage electrical signal is directly input to the variable amplifier 12e. The other is switched to the second signal adjustment circuit 12d2 (step S1), and the register is set so that the gain of the variable amplifier 12e is 10 dB (step S2).

  Next, based on the setting table, the selection destination of the first selection circuit 12a is switched to the second input terminal 11b so that the electrical signal from the illuminance sensor 2b is input into the signal adjustment circuit 12 (step S3). .

  The input electric signal is amplified to a set level by the variable amplifier 12e after the high frequency component is removed by the filter 12b. The amplified DC voltage electrical signal is input to the microcontroller 13 and converted to a digital value by the A / D converter 13a. At this time, in order to suppress the influence of noise, the A / D converter 13a performs an averaging process after sampling the digital value a predetermined number of times (steps S4 to S6).

  Next, processing of electrical signals from the analog current output sensor 2c will be described.

  First, the control unit 13c in the microcontroller 13 selects the second selection circuit 12c based on the setting table acquired from the storage unit 13b so that the input direct current electric signal is directly input to the variable amplifier 12e. The former is switched to the second signal adjustment circuit 12d2 (step S1), and the register is set so that the gain of the variable amplifier 12e is 1 dB (step S2).

  Next, based on the setting table, the selection destination of the first selection circuit 12a is switched to the third input terminal 11c so that the electric signal from the analog current output sensor 2c is input into the signal adjustment circuit 12 (step) S3).

  After the high frequency component is removed by the filter 12b, the input signal is converted to a voltage by the load resistor R1, and amplified to a preset level by the variable amplifier 12e.

  Thereafter, the converted and amplified DC voltage electrical signal is input to the microcontroller 13 and converted to a digital value by the A / D converter 13a. At this time, in order to suppress the influence of noise, the A / D converter 13a performs an averaging process after sampling the digital value a predetermined number of times (steps S4 to S6).

  Finally, processing of the electrical signal from the analog voltage output sensor 2d will be described.

  First, the control unit 13c in the microcontroller 13 selects the second selection circuit 12c based on the setting table acquired from the storage unit 13b so that the input DC voltage electrical signal is input to the voltage dividing resistor R2. The former is switched to the fourth signal adjustment circuit 12d4 (step S1), and the register is set so that the gain of the variable amplifier 12e becomes 1 dB (step S2).

  Next, based on the setting table, the selection destination of the first selection circuit 12a is switched to the fourth input terminal 11d so that the electrical signal from the analog voltage output sensor 2d is input to the inside of the signal adjustment circuit 12 (step S11). S3).

  After the high frequency component is removed by the filter 12b, the input electric signal is adjusted to a voltage range suitable for the A / D converter 13a by resistance division by the voltage dividing resistor R2, and is set by the variable amplifier 12e. Is amplified.

  Thereafter, the adjusted / amplified DC voltage electric signal is input to the microcontroller 13 and converted into a digital value by the A / D converter 13a. At this time, in order to suppress the influence of noise, the A / D converter 13a performs an averaging process after sampling the digital value a predetermined number of times (steps S4 to S6).

  Then, the control unit 13c refers to all the correspondence data stored in the setting data, and for each of the correspondence data, the selection destination switching operation in the first selection circuit 12a and the selection in the second selection circuit 12c. The previous switching operation and the gain value changing operation in the variable amplifier 12e are repeatedly executed while being synchronized.

  That is, in the case of the above operation example, an operation of switching the selection destination of the first selection circuit 12a to the first input terminal 11a, and an operation of switching the selection destination of the second selection circuit 12c to the first signal adjustment circuit 12d1. The operation of setting the register so that the gain of the variable amplifier 12e is 6 dB is executed at the same timing. Then, the operation of switching the selection destination of the first selection circuit 12a to the second input terminal 11b, the operation of switching the selection destination of the second selection circuit 12c to the second signal adjustment circuit 12d2, and the variable amplifier 12e The operation of setting the register so that the gain of 10 dB becomes 10 dB is executed at the same timing. Thereafter, the same process is repeated based on the setting data.

  In consideration of reducing the time required for switching between the first selection circuit 12a and the second selection circuit 12c and the time lag in sensor data acquisition as much as possible, the predetermined number of samplings is performed within 50 ms. It is desirable.

  As described above, by controlling the switching operation of the first selection circuit 12a and the switching operation of the second selection circuit 12c in synchronization, various types of electrical signals (DC voltage, AC voltage, DC current) are controlled. , Alternating current) can be measured, and by changing the gain value of the variable amplifier 12e, the electric signal from the sensor 2 can be acquired in a wide measurement range.

  Therefore, if the data from the sensor 2 is acquired by sequentially switching the second selection circuit 12c for an input signal whose type of electrical signal is unknown, the type of the input signal and the subsequent stage to be selected from the profile of the data. It is possible to set the signal adjustment circuit 12d. In addition, if data is acquired by sequentially switching the gain value of the variable amplifier 12e with respect to the same input signal whose type of electrical signal is known, it is possible to measure from a small signal to a large signal at one time, and the optimum gain A value can be set.

  In the present embodiment, the selection destination switching operation in the first selection circuit 12a, the selection destination switching operation in the second selection circuit 12c, and the gain value changing operation in the variable amplifier 12e are temporally performed. Therefore, data from a plurality of sensors 2 having different types and levels of electric signals can be efficiently acquired with a minimum circuit. It can be said that the larger the number of sensors 2 is, the larger the circuit scale reduction effect is.

  In the present embodiment, the operation of acquiring the four sensor data with the same cycle has been described, but the cycle may be different for each sensor 2. In this case, the order of the sensors 2 to be controlled is not the same but is nested according to a set cycle.

[Second Embodiment]
FIG. 5 is a diagram illustrating a configuration example of the sensor terminal 1 according to the second embodiment. In the present embodiment, the first selection circuit 12a is connected between the power supply terminals of the plurality of sensors 2 and the power supply circuit in the microcontroller 13, and the terminal block 11 and the filter 12b are directly connected. doing.

  The first selection circuit 12a in this example selects one of the plurality of sensors 2 based on a control signal from the control unit 13c based on the setting table, and supplies power from the power supply circuit to the selected sensor 2. Supply. The sensor 2 to be operated is selected by controlling on / off of the sensor 2 depending on whether or not power is supplied.

  Even in the case of the present embodiment, since any one of the sensors 2 is selected by the first selection circuit 12a and an electric signal from the selected sensor 2 is input to the sensor terminal 1, the first implementation is performed. It is possible to obtain the same effect as the embodiment. That is, while the selection destination switching operation in the first selection circuit 12a, the selection destination switching operation in the second selection circuit 12c, and the gain value changing operation in the variable amplifier 12e are synchronized in time. By repeatedly executing the data, it is possible to efficiently acquire data from a plurality of sensors 2 having different types and levels of electric signals with a minimum circuit.

  As described above, according to each embodiment, the circuit scale can be reduced even when the number of connected sensors is increased. Therefore, downsizing and cost reduction can be realized while maintaining the versatility of the sensor terminal 1.

DESCRIPTION OF SYMBOLS 1 ... Sensor terminal 11 ... Terminal block 11a-11d ... 1st input terminal-4th input terminal 12 ... Signal adjustment circuit 12a ... 1st selection circuit 12b ... Filter 12c ... 2nd selection circuit 12d ... Signal adjustment circuit 12d1 to 12f4 ... 1st signal adjustment circuit to 4th signal adjustment circuit 12e ... Variable amplifier 12f ... Changeover switch 12g ... Amplifier 13 ... Microcontroller 13a ... A / D converter 13b ... Storage unit 13c ... Control unit 14 ... Memory DESCRIPTION OF SYMBOLS 15 ... Communication module 16 ... Power supply part 2 ... Sensor 2a ... Clamp type alternating current sensor 2b ... Illuminance sensor 2c ... Analog current output sensor 2d ... Analog voltage output sensor 3 ... Base station 4 ... Router 5 ... Optical line 6 ... Server C, C1, C2 ... Rectifier circuit R, R1 ... Load resistance R2 ... Voltage-dividing resistor S1-S6 ... Step

Claims (3)

A first selection circuit for selecting one of a plurality of sensors;
A plurality of signal adjustment circuits for adjusting the electrical signal from the sensor according to the type of the electrical signal,
A second selection circuit that selects any one of the plurality of signal adjustment circuits and outputs an electrical signal from a sensor selected by the first selection circuit to the selected signal adjustment circuit;
A variable gain amplifier for amplifying an electric signal from the signal adjustment circuit selected by the second selection circuit;
Based on the corresponding data in which the sensor and the type of the electrical signal and the gain value corresponding to the type of the sensor and the electrical signal are associated, each selection destination of the first selection circuit and the second selection circuit is switched, A controller for changing the gain value of the variable gain amplifier,
The plurality of signal adjustment circuits share a resistor in the plurality of signal adjustment circuits,
The controller is
Each of the correspondences is performed while synchronizing the selection destination switching operation in the first selection circuit, the selection destination switching operation in the second selection circuit, and the gain value changing operation in the variable gain amplifier. A sensor terminal that is repeatedly executed for data. The first selection circuit includes:
The sensor terminal according to claim 1, wherein the sensor terminal is connected between the plurality of sensors and the second selection circuit. The first selection circuit includes:
The sensor terminal according to claim 1, wherein the sensor terminal is connected between a power supply terminal of each of the plurality of sensors and a power supply.

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