JPH07159196A - Sensor signal processing device - Google Patents

Abstract

PURPOSE:To eliminate regulation for each unit of sensor, and deal with sensors of different specifications with a common hardware by providing an amplifica tion factor regulation circuit and an offset regulation circuit. CONSTITUTION:An atmospheric pressure PI is applied to an atmospheric pressure sensor 1, and an offset regulation signal S0 to input 7a/output 7b an offset reduction pattern of offset regulation data Do0 is reduced. Offset voltage value at an amplification circuit 3 is then reduced. Next, an, atmospheric pressure P2 is applied to the sensor 1, and amplification factor regulation signal Sg to input 8a/output 8b amplification factor increasing pattern of amplification factor regulation data Dg is increased. An amplification factor at the circuit 3 is then increased. By providing an offset regulation circuit 7 and an amplification factor regulation circuit 8, regulation by the unit of sensor is not required even for a sensor of which sensitivity and offset irregularity is large, so sensor completion yield is improved. Even in the case where sensors of different specifications are used, common hardware can be applied, thereby regulation processes can be simplified, with the cost reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor signal processing device for processing an output signal of a sensor for detecting physical information for the purpose of displaying or the like.

[0002]

2. Description of the Related Art Recent electronic timepieces have not only original timetable functions, alarms, commonly used functions such as chronographs, but also physical information such as atmospheric pressure and water pressure, and constantly changing physical information. A sensor having a sensor function of measuring with a sensor and displaying the signal via a signal processing circuit has been commercialized. However, the electronic timepiece has a limited space for accommodating electronic circuit elements, and in order to reduce the cost, elements such as variable resistors for adjusting the amplification factor and offset are not used as much as possible. However, no adjustment is required. Furthermore, it is desirable that the same hardware can support sensors with different specifications.
A conventional technique relating to the above constraint conditions will be described below.

FIG. 2 shows an example of a conventional sensor signal processing device used in a battery-driven electronic timepiece. In FIG.
Reference numeral 1 is an atmospheric pressure sensor that outputs an atmospheric pressure signal S1 proportional to the atmospheric pressure P. 2 is a sensor drive circuit that drives by supplying a constant current to the atmospheric pressure sensor 1. 3 is an amplifier circuit that amplifies the atmospheric pressure signal S1 using an operational amplifier. The A / D conversion circuit 5 for A / D converting the amplified atmospheric pressure signal S1 ′ output from the amplification circuit 3 and outputting it as conversion data Dc, processes the conversion data Dc to convert it into sensor information data Dj and outputs it. The sensor information data processing circuit is a memory setting circuit 5a, the first memory is an A memory 5b, the second memory is a B memory 5c, a data selection circuit 5d, and a sensor characteristic formula calculating means micro. It is composed of a computer.
The memory setting circuit 5a externally converts the conversion data Dc input from the A / D conversion circuit 4 to the terminal I into the terminals C1 and C.
2 is output from the terminal O1 or the terminal O2 according to the control signal S31 or S32 input to the A memory 5
b or B memory 5c. Memory setting circuit 5
When the conversion data Dc is output from the terminal O1 of a, the conversion data Dc is stored in the A memory 5b as the memory data Da. When the conversion data Dc is output from the terminal O2, the conversion data Dc is stored in the B memory 5c as the memory data Db. The A memory 5b and the B memory are flash generation memories, and the memory setting circuit 5
When stored by a, the contents are retained even when the power is turned off. The data selection circuit 5d receives the conversion signal Dc input to the terminal I1 or the memory data Da, which is the storage content of the A memory 5b input to the terminal I2, according to the control signal input from the microcomputer 5e to the terminal C. Either the memory data Da, which is the storage content of the B memory 5c input to the terminal I3, is selectively output from the terminal O and supplied to the microcomputer 5e. The microcomputer 5e controls the terminal C of the data selection circuit 5d to read the memory data Da stored in the A memory 5b and the memory data Db stored in the B memory 5c from the terminal O of the data selection circuit 5d. , The sensor characteristic formula is determined, and the sensor information signal Dj is output to the display device 6. Reference numeral 6 denotes a display device for digitally displaying the atmospheric pressure value based on the sensor information data Dj output from the microcomputer 5e of the sensor information data processing circuit 5.

The sensor signal processing device having the above circuit configuration operates as follows. When the atmospheric pressure sensor 1 is driven with a constant current by the sensor drive circuit 2, the atmospheric pressure sensor 1 outputs an atmospheric pressure signal S1 proportional to the atmospheric pressure P applied to the atmospheric pressure sensor 1. The atmospheric pressure signal S1 is amplified by the amplifier circuit 3 into a signal S1 ′, and this signal S1 ′ is further converted into digital conversion data Dc by the A / D conversion circuit 4. The digital conversion data Dc is converted into the sensor information D by the sensor information data processing circuit.
is converted into j, but here the sensor information data processing circuit 5
A method of calculating the sensor characteristic formula in will be described. First, a certain atmospheric pressure P1 is applied to the atmospheric pressure sensor 1, and in this state, the control signal S31 is externally input to the terminal C1 of the memory setting circuit 5a and the conversion data Dc output from the A / D conversion circuit 4 is stored in the A memory. Store in 5b. Next, pressure P1
The atmospheric pressure P2 different from that is applied to the atmospheric pressure sensor 1, and in this state, the control signal S32 is externally applied to the terminal C2 of the memory setting circuit 5a.
And the converted data Dc output from the A / D conversion circuit 4 is stored in the B memory 5c. As shown in FIG. 3, the conversion data Dc at the atmospheric pressure P1 is converted into the memory data D
That is, it is stored in the A memory 5b as a, and the converted data Dc at the atmospheric pressure P2 is stored in the B memory 5c as memory data Db. That is, the barometric pressure conversion characteristics that combine the characteristics of the barometric pressure sensor 1 and the characteristics of the amplifier circuit 3 are displayed in the A memory 5b.
And B memory 5c. Next, the calculation of the sensor characteristic formula by the microcomputer 5e will be described. The microcomputer 5e is a data selection circuit 5d
By controlling the terminal C of the memory data Da stored in the A memory 5b (conversion data Dc at the atmospheric pressure P1)
And the memory data Db stored in the B memory 5c
(Conversion data Dc at atmospheric pressure P2) is read, α and β are calculated, and the sensor characteristic formula shown by the following formula 1 for determining the sensor information signal Dj is determined.

[0005]

## EQU1 ## Dj = α × Dc + β α = (P2-P1) / (Db-Da) β = P1-α × Da

It should be noted that the determination of α and β in the sensor characteristic formula may be performed only once based on the memory data Da and Db stored in the non-light emission generating memory when the power is turned on. Once the sensor characteristic equation of the equation 1 is determined, the conversion data Dc is thereafter read into the microcomputer 5e through the data selection circuit 5d, and the sensor information signal Dj (representing the atmospheric pressure P is expressed by the sensor characteristic equation of the equation 1). ) Is calculated. Now, when the digital conversion data Dc is inputted from the A / D conversion circuit 4 to the sensor information data processing circuit 5 having the sensor characteristic formula thus determined, the sensor information signal Dj calculated according to the sensor characteristic formula is transferred to the microcomputer 5e. Is output from. The display device 6 determines the atmospheric pressure value (for example, 1013 hP based on the sensor information signal Dj).
Display a).

[0007]

As described above, since the sensor characteristic equation is calculated and determined for each sensor signal processing device so as to match the characteristic of the atmospheric pressure sensor and the characteristic of the amplification circuit, the mechanical characteristic formula is determined. The atmospheric pressure can be displayed accurately without any adjustment. However, in the sensor actually used, there are large variations in sensitivity and offset,
In the conventional sensor signal processing device, adjustment of the sensor alone is forced, and if it is out of the standard, it will be treated as bad and the yield of sensor completion will be reduced, and the upper limit of atmospheric pressure to be measured will be taken into consideration in consideration of the sensitivity and offset variation of the sensor. Even at Pmax, A does not exceed the upper limit value Dmax of A / D conversion, or at the lower limit value Pmin of the atmospheric pressure to be measured, A
As shown in FIG. 4 (a), it does not become 0 which is the lower limit value of the / D conversion.
As shown in Fig. 4, the setting of the amplification factor of the amplification circuit 3 is shown in Fig. 4.
As shown in FIG. 4 (b), since it is necessary to set each offset, it is difficult to effectively use the dynamic range as shown in FIGS. 4 (a) and 4 (b), and it is difficult to increase the resolution per unit atmospheric pressure. Met. Further, when using sensors with different specifications, it is necessary to reset the amplification factor and the offset of the amplifier circuit 3 according to the characteristics of the sensors, which makes it difficult to change the specifications. It is an object of the present invention to provide a sensor signal processing device which can eliminate adjustment of the sensor alone and can handle sensors with different specifications with common hardware.

[0008]

In order to achieve the above object, the present invention has the following constitution. That is, the sensor signal processing device according to the present invention includes a linear sensor that detects physical information, a sensor drive circuit that drives the sensor,
An amplifier circuit for inputting and amplifying a sensor signal output from the sensor, an A / D converter circuit for converting the amplified output value processed by the amplifier circuit into digital information, and an output from the A / D converter circuit. A data processing circuit for creating sensor information data from digital information and the data processing circuit
A first memory and a second memory respectively storing two different digital information data output from the / D conversion circuit, and a sensor characteristic formula based on the two digital information data stored in the two memories. A sensor signal processing device for calculating digital information data output from the A / D conversion circuit according to the sensor characteristic formula calculated by the sensor characteristic formula calculating unit An amplification factor adjustment circuit for adjusting an amplification factor of the amplification circuit and an offset adjustment circuit for adjusting an offset voltage value of the amplification circuit are provided.

[0009]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of the sensor signal processing device according to the present invention, and the sensor signal processing device illustrated here is designed to display the atmospheric thickness. The present invention will be described below with reference to this drawing. In the figure, the same elements as those in FIG. Reference numeral 7 denotes an offset adjustment circuit, which is composed of an offset adjustment memory 7a and an offset adjustment D / A conversion circuit 7b. The offset adjustment memory 7a stores the offset adjustment data Do represented by a digital value input from the outside, and outputs the offset adjustment data Do to the offset adjustment D / A converter 7b. Offset adjustment D / A converter 7
b generates an offset adjustment signal So based on the offset adjustment data Do and supplies it to the amplification unit 4. Reference numeral 8 denotes an amplification factor adjusting circuit, which is composed of an amplification factor adjusting memory 8a and an amplification factor switching circuit 7b. Amplification factor adjustment memory 8a
Is the digital amplification factor adjustment data Dg input from the outside.
And outputs the amplification factor adjustment data Dg to the amplification factor switching circuit 8b. The amplification factor switching circuit 8b generates an amplification factor adjustment signal Sg based on the amplification factor adjustment data Dg and supplies it to the amplification circuit 3. The amplifier circuit 3 switches the input or feedback resistance value of the operational amplifier based on the amplification factor adjustment signal Sg to determine the amplification factor. The offset adjustment memory 7a and the amplification factor adjustment memory 8a are flash generation memories, and their contents are retained even if the power is turned off after storing the data.

Next, the operation of the sensor signal processing apparatus according to the present invention having the above structure will be described. Now, FIG. 5A shows a graph of the A / D converted value when an atmospheric pressure sensor having an offset value that is too large and sensitivity is too low is used. Figure 5
In the state of (a), the upper limit Pmax to be measured exceeds the upper limit Dmax of the measurement limit because the offset value is too large. Therefore, not only the desired measurement range cannot be obtained, but also the sensitivity of the barometric pressure sensor 1 is too low.
The weighting per bit of c is too large and the measurement resolution becomes rough. A procedure for adjusting the sensor signal processing device will be described below. First, the atmospheric pressure P1 is applied to the atmospheric pressure sensor 1, and in this state, an offset reduction pattern of the offset adjustment data Do is externally input to the offset adjustment memory 7a to output the offset adjustment signal So output from the offset adjustment D / A conversion circuit 7b. cut back. Then, the offset voltage value in the amplifier circuit 3 decreases, and the atmospheric pressure P1
A graph of the A / D converted value at P2 and P2 is shown in FIG.
As shown in. Next, the atmospheric pressure P2 is applied to the atmospheric pressure sensor 1, and in this state, the amplification factor adjustment pattern of the amplification factor adjustment data Dg is externally input to the amplification factor adjustment memory 8a, and the amplification factor adjustment signal output from the amplification factor switching circuit 8b. Increase Sg. Then, the amplification factor in the amplifier circuit 3 increases and the atmospheric pressure P
The graph of the A / D conversion value in 1 and P2 is shown in FIG.
As shown in (c).

After the sensor signal processing device is roughly adjusted as described above, the atmospheric pressure P1 is applied to the atmospheric pressure sensor 1 as described in the prior art, and in this state, the control signal S31 is externally applied to the terminal C1 of the memory setting circuit 5a. Input conversion data Dc output from the A / D conversion circuit 4 to the A memory 5b.
Remember. Next, the atmospheric pressure P2 is applied to the atmospheric pressure sensor 1, and in this state, the control signal S32 is externally input to the terminal C2 of the memory setting circuit 5a and the conversion data Dc output from the A / D conversion circuit 4 is stored in the B memory 5c. To do. Then, the microcomputer 5e controls the terminal C of the data selection circuit 5d so that the memory data Da stored in the A memory 5b (conversion data Dc at the atmospheric pressure P1) and the memory data stored in the B memory 5c. Db (conversion data Dc at atmospheric pressure P2) is read, α and β are calculated, and the sensor characteristic formula shown by the following equation 1 for determining the sensor information signal Dj is determined. When the digital conversion data Dc is input from the A / D conversion circuit 4 to the sensor information data processing circuit 5 having the sensor characteristic formula thus determined,
The sensor information signal Dj calculated according to the sensor characteristic formula is output from the microcomputer 5e. Display device 6
Displays the atmospheric pressure value (for example, 1013 hPa) based on the sensor information signal Dj.

[0012]

As is apparent from the above description, according to the present invention, by providing an offset adjusting circuit and an amplification factor adjusting circuit, even a sensor having a large variation in sensitivity and offset does not require adjustment of the sensor alone. The completed yield can be improved, and even if sensors with different specifications are used, common hardware can be used, which has a great effect on simplification of the adjustment process and cost reduction.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a sensor processing device of the present invention.

FIG. 2 is a circuit block diagram showing a conventional sensor processing device.

FIG. 3 is a graph showing an A / D conversion value with respect to atmospheric pressure in a conventional example.

FIG. 4 is a graph showing an A / D conversion value with respect to atmospheric pressure in a conventional example.

FIG. 5 is a graph showing A / D conversion values with respect to atmospheric pressure according to the present invention.

[Explanation of symbols]

 1 barometric pressure sensor 2 sensor drive circuit 3 amplification circuit 4 A / D conversion circuit 6 display device 7 offset adjustment circuit 8 amplification factor adjustment circuit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroyuki Kihara 6-12 Hommachi Honmachi, Tanashi City, Tokyo Citizen Watch Co., Ltd. Tanashi Factory

Claims (1)

[Claims] 1. A linear sensor for detecting physical information, a sensor drive circuit for driving the sensor, an amplifier circuit for inputting and amplifying a sensor signal output from the sensor, and a processor processed by the amplifier circuit. An A / D conversion circuit that converts the amplified output value into digital information, a data processing circuit that creates sensor information data from the digital information output from the A / D conversion circuit, and the data processing circuit is an A / D conversion circuit A first memory and a second memory for respectively storing two different digital information data output from
A sensor characteristic formula calculating means for calculating a sensor characteristic formula based on two digital information data stored in one memory, and the A / D conversion circuit according to the sensor characteristic formula calculated by the sensor characteristic formula calculating means. In the sensor signal processing device for converting the digital information data output from the sensor information data, an amplification factor adjusting circuit for adjusting the amplification factor of the amplification circuit, and an offset for adjusting the offset voltage value of the amplification circuit. A sensor signal processing device comprising an adjusting circuit.