JPH0587570A - Electronic timepiece fitted with depth meter - Google Patents

Abstract

PURPOSE:To avoid the erroneous display of the depth of water caused by the offset change of the amplifying circuit incorporated in an exterior case generated by a clocking change in the timepiece. CONSTITUTION:Pressure memory data Da, Db of two different values necessary for a calculation formula for measuring the depth of water and an A/D conversion value Dc again taken under the same pressure of either one of the memory data after an amplifing circuit is incorporated in an exterior case are compared by a sensor data processing circuit 50 and the comparison result is displayed on a display device 6. The offset of the amplifying circuit can be confirmed in the state incorporated in the exterior case and can be simply calibrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic timepiece equipped with a water depth gauge for preventing an erroneous water depth indication due to a semiconductor sensor assembling work for detecting water pressure or time-dependent fluctuation.

[0002]

2. Description of the Related Art The construction of a conventional electronic timepiece with a water depth gauge is shown in FIG.
It will be explained based on. Reference numeral 1 denotes a semiconductor pressure sensor utilizing the piezo effect, which outputs a voltage Vp proportional to the pressure P. Hereinafter, a semiconductor pressure sensor will be referred to as a pressure sensor) 2 is a sensor drive circuit, which is a drive circuit for supplying a constant current to the pressure sensor 1 to drive it. Reference numeral 3 is an amplifier circuit, and the amplifier circuit 3 has a fixed amplification factor without sensitivity adjustment and offset adjustment. Therefore, the sensor voltage V
s is amplified to a constant magnification and output as an amplified voltage Va. Reference numeral 4 denotes an A / D conversion circuit, which inputs the amplified voltage Va and outputs A / D conversion data Dc in synchronization with a timing signal S of a microcomputer 55 described later. 5
Reference numeral 0 denotes a sensor information processing circuit, which is composed of a memory setting circuit 51, a first memory A52, a second memory B53, a data selection circuit 54, and a sensor characteristic formula calculation microcomputer 55. ..
The memory setting circuit 51 outputs the conversion data Dc input from the A / D conversion circuit 4 to the terminal I from the terminal O1 or the terminal O2 according to the external control signal Pc input to the terminal C, and outputs the memory A52 or the memory B53. Remember. When the conversion data Dc is output from the terminal O1 of the memory setting circuit 51, the conversion data Dc is stored in the memory A52 as the memory data Da. On the other hand, when the converted data Dc is output from the terminal O2, the converted data Dc is stored in the memory B.
It is stored in 53 as memory data Db. The memories A52 and B53 are non-volatile memories, and when stored by the memory setting circuit 51, their contents are retained even when the power is turned off. The data selection circuit 54 is input to the conversion data Dc input to the terminal I1 or the conversion data Da input to the terminal I2 or the terminal I3 according to the control signal of the microcomputer 55 supplied to the terminal C. The conversion data Db is selectively applied to the terminal O
Then, it is supplied to the microcomputer 55, converted into sensor information data Dj, and output. A display device 6 inputs the sensor information data Dj and displays the value.

The operation of the sensor signal processing device having the above configuration will be described. Usually, this operation is performed before the sensor and the circuit are incorporated in the watch case. First, a method of calculating a sensor characteristic formula for outputting water depth data will be described. Conversion data output from the A / D conversion circuit 4 by applying a certain pressure P1 (for example, 1 atm absolute pressure) to the sensor 1 and inputting an external control signal Pc to the C terminal of the memory setting circuit 51 in this state. Dc is stored in the memory A52. Next, pressure P2 higher than pressure P1 (for example, absolute pressure 6
(Atmospheric pressure) is applied to the pressure sensor, and the external control signal Pc of the memory setting circuit 51 is input in this state to input the A / D conversion circuit 4
The converted data Dc output from is stored in the memory B53.

This is because the converted data Dc when the pressure is P1 is used as the memory data Da as shown in FIG.
The converted data Dc for the pressure P2 is stored in the memory B53 as the memory data Db. Next, the calculation of the sensor characteristic formula by the microcomputer 55 will be described. The microcomputer 55 controls the terminal C of the data selection circuit 54 to control the memory data Da (conversion data Dc when the pressure is P1) stored in the memory A52 and the memory data Db (pressure that is stored in the memory B52). The conversion data Dc) for P2 is read, α and β are calculated, and the sensor characteristic formula (1) is determined.

Dj = α × Dc + β (1) α = (P2-P1) / (Db-Da) β = P1-α × Da Note that this sensor characteristic formula (1) is determined when the power is turned on. 1
You only have to do it once. The sensor characteristic equation (1) is for converting the conversion data Dc generated by the pressure P applied to the pressure sensor into the sensor information signal Dj as the display information. Once the sensor conversion formula (1) is determined, the conversion data Dc is subsequently read by the microcomputer 55 via the data selection circuit 54, and the sensor characteristic formula (1) is obtained.
Then, Dj (equal to the pressure P) is calculated in the sensor information signal and displayed as the pressure on the display device 6.

[0006]

However, the water depth accuracy fluctuates after being incorporated in the timepiece outer case or when the user uses it for a long period of time. That is, the memory data Da (pressure P1) stored in the memory A52
Offset data of the amplifier circuit 3 at the time of writing the conversion data Dc) at the time of writing and the memory data Db stored in the memory B53 (the conversion data Dc at the time of pressure P2) and the stress at the time of assembling into the watch case. It was because the value changed. The above phenomenon will be described with reference to FIGS. 3 and 4. FIG. 3 is a graph of the pressure P and the A / D conversion value Dc, and L1 is a straight line when the memory data Da and Db are written. L2 is an amplifier circuit 3 when assembled in an outer case
It is a straight line when the offset value of changes to the "+" side. Dk is a permissible offset deviation range under the pressure P1, and is a range in which the A / D conversion circuit 4 can measure water depth without any problem in normal use even if the offset value of the amplifier circuit 3 is slightly deviated. Dk1 indicates the lower limit value of the allowable range, and Dk2 indicates the upper limit value of the allowable range. Since the A / D conversion value Dc (= memory data Da) is within the offset deviation allowable range Dk on the straight line L1 under the pressure P1, the A / D conversion value Dh1 for the maximum pressure Ph at which a human can dive is A / D. The pressure can be measured without exceeding Dmax, which is the limit value that the D conversion circuit 4 can follow. However, the straight line L
At 2, the A / D converted value Da ′ at the time of pressure P1 exceeds the upper limit value Dk2 of the offset deviation allowable range Dk, and therefore the limit value Dmax is reached at the time of pressure Ph, and measurement becomes impossible.

Similarly, the amplifier circuit 3 when assembled in the outer case
The case where the offset value of is changed to the "-" side is shown below. FIG. 4 is a graph of the pressure P and the A / D conversion value Dc as in FIG. 3, and L1 is a straight line when the memories Da and Db are written. L4 is a straight line when the offset value of the amplifier circuit 3 changes to the "-" side when incorporated in the outer case. The straight line L4 is below the lower limit value Dk1 of the offset deviation allowable range Dk under the pressure P1. Also pressure P3
Even when the pressure reaches P1, the A / D conversion value Dc is 0, and the pressure P1
Since the measurement from the pressure to the pressure P3 cannot be performed at all, the sensor information signal Dj shows a lower value than the actual value when diving.

However, in the conventional electronic timepiece with a water depth gauge, the offset could not be confirmed and calibrated while being incorporated in the outer case, so that the above-mentioned drawback may be overlooked, which is very dangerous.

It is an object of the present invention to provide an electronic timepiece with a water depth gauge, which can improve the above-mentioned drawbacks and can confirm the amount of offset deviation even after the semiconductor pressure sensor, the amplifier circuit and the like are incorporated in an outer case.

[0010]

To achieve the above object, the structure of the present invention is as follows. A semiconductor pressure sensor for detecting external water pressure, a sensor drive circuit for driving the semiconductor pressure sensor, an amplifier circuit for amplifying an output voltage from the semiconductor pressure sensor, and an offset voltage for adjusting the amplifier circuit. A resistance selection circuit, an A / D conversion circuit for A / D converting the amplified voltage of the amplification circuit at a constant cycle, and two different A / Ds from the A / D conversion circuit.
A first arithmetic unit having a first memory and a second memory for storing the converted data, and for calculating a sensor characteristic formula for outputting the water depth data based on the data stored in the two memories. And a sensor information data processing circuit having a second arithmetic means for converting the A / D converted data from the A / D conversion circuit into water depth data according to the sensor characteristic formula, and a display means for displaying the water depth data. In the electronic timepiece having a water depth meter, the first memory or the second memory
One of the data stored in the memory is compared with the A / D conversion data having the same pressure as the time when the data in the memory was stored, and the comparison data is displayed by the display means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic timepiece with a water depth gauge according to the present invention will be described below with reference to the drawings. 1 to 5 show an embodiment of an electronic timepiece with a water depth gauge according to the present invention. 1 is a system block diagram, FIG. 2 is a flowchart art diagram of a calculation means for displaying an offset amount of the amplifier circuit 3 in the configuration diagram shown in FIG. 1, and FIGS. 3 and 4 are pressure P of the circuit operation shown in FIG. FIG. 5 is a graph showing the A / D conversion value Dc, and FIG. 5 is a circuit diagram showing the offset adjustment resistance selection circuit. In FIG. 1, the same elements as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.
The structure of the present invention is as follows.

S1 is a data comparison request terminal, which is input to the microcomputer 55. Reference numeral 100 denotes an offset adjustment resistance selection circuit, which is connected to the amplification circuit 3 via terminals A and B. The configuration of the offset adjustment resistance selection circuit 100 is as shown in FIG.
Reference numeral 2 is a pull-down resistor, and the pull-down resistor 101 has one side connected to the ground and the other side connected to "+" and the T1 terminal. The pull-down resistor 102 has one side connected to ground and the other side connected to "+" and the T2 terminal. 105, 1
06 and 107 are 2-input AND gates (hereinafter referred to as AN
The D gate is referred to as AND), one input of the AND 105 is connected to the T1 terminal, and the other input is connected to the T2 terminal. One input of the AND 106 is connected to the T1 terminal via the inverter 103 (hereinafter, the inverter will be referred to as INV), and the other input is connected to the T2 terminal. One input of the AND107 is connected to the T1 terminal and the other input is connected to the T2 via the INV104.
It is connected to the terminal. 111, 112 and 113 are transmission gates (hereinafter the transmission gate is referred to as TG), and the control signal is "
It becomes "ON" at the "H" level and "OFF" at the "L" level. The control signal of the TG111 is the AND1.
05, one terminal 111a is connected to the terminal A, and the other terminal 111b is connected to the terminal B through the resistor Rm. The control signal of the TG112 is the AND10
6, one terminal 112a is connected to the terminal A, and the other terminal 112b is connected to the terminal B through the resistor RS. The control signal of the TG113 is the AND10
7, one terminal 113a is connected to the terminal A, and the other terminal 113b is connected to the terminal B via the resistor Rb. The relationship between the resistance values of the resistance RS, the resistance Rb, and the resistance Rm is resistance Rb> resistance Rm> resistance RS.

The operation of the electronic timepiece with a water depth gauge according to the present invention having the above structure will be described with reference to FIGS. 1, 2 and 3. When the data comparison request terminal S1 shown in FIG. 1 is set to "H", the microcomputer 55 controls the terminal C of the data selection circuit 54 to take in the data Da of the contents of the memory A. Next, the microcomputer 55 outputs the timing signal S and inputs the conversion data Dc at the time of pressure P1.
Further, the offset amount Dj1 is calculated by the following offset formula (2),

Dj1 = α (Dc-Da) (2) α = (P2-P1) / (Db-Da) Subsequently, the microcomputer 55 sets the lower limit value display data formula (3) and the upper limit value display data. Formula (4) is calculated. Dj2 = α (Da−Dk1) ··· (3) Dj3 = α (Dk2-Da) ··· (4) When the offset amount Dj1 becomes positive according to the offset equation (2), the microcomputer 55 The offset amount Dj1 and the upper limit value display data Dj3 are sent to the display device 6 as the sensor information signal Dj. If it becomes negative, the microcomputer 55 causes the display device 6 to display the sensor information signal Dj.
As offset amount Dj1 and lower limit value display data Dj2
To send.

If the offset amount Dj1> the upper limit display data Dj3, the following correction is performed. L3 shown in FIG. 3 is a straight line obtained by calibrating the straight line L2 when the offset value of the amplifier circuit 3 changes to the "+" side when incorporated in the outer case. The calibration method in this case is as follows. In the resistance selection circuit 100 of FIG. 5, "H" level is supplied to the normal terminal T1 and the terminal T2, and only the AND105 is used.
The H "level is output and the TG 111 is in the" ON "state. Therefore, the resistor Rm is connected between the terminals A and B. The" H "level side connection supplied to the terminal T1 is cut. Set it to L "level.
It goes to L "level and TG111 turns to" OFF ". Instead, AND106 goes to" H "level and TG112
Is "ON" and a resistor RS is connected between terminals A and B.
That is, by connecting the resistor RS between the terminals A and B, the offset value of the amplifier circuit 3 is lowered and the straight line L2 is moved to the straight line L3. In the case of the straight line L3, the pressure is within the offset deviation allowable range Dk under the pressure P1, and even if the human reaches the pressure Ph capable of diving, the pressure is measured as the A / D conversion value Dh1 ′ without exceeding the limit A / D conversion value Dmax. It can be performed.

Similarly, the amplifier circuit 3 when assembled in the outer case
When the offset value of is changed to the "-" side and the lower limit value display data Dj2> | offset amount Dj1 |, the following correction is performed. As shown in Fig. 4, L5 is the offset value of the amplifier circuit 3 due to the stress when assembled in the outer case.
This is a straight line obtained by calibrating the straight line L4 when it changes to the "-" side. The calibration method in this case is that the "H" level side connection supplied to the terminal T2 in the resistance selection circuit 100 in FIG. Cut to "L" level and then AND
105 becomes "L" level and TG111 is "OFF"
To do. Instead, AND107 goes to "H" level and T
G113 is "ON", and the resistor RS is connected between the terminals A and B. That is, by connecting the resistor Rb between the terminals A and B, the offset value of the amplifier circuit 3 is increased and the straight line L4 is moved to the straight line L5. Pressure P for straight line L5
It is within the offset deviation allowable range Dk under 1 and A / D
The pressure can be measured as the A / D converted value Da ″ without the converted value becoming 0.

[0017]

As is apparent from the above embodiments, according to the present invention, even if there is offset rubbing of the amplifier circuit when it is incorporated in the exterior, it is possible to confirm the offset rubbing in the state of being incorporated in the exterior. The present invention provides a timepiece with a water depth gauge that can prevent the erroneous water depth measurement due to the above causes.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of the present invention.

FIG. 2 is a flowchart of the present invention.

FIG. 3 is a graph showing the A / D conversion value Dc with respect to the pressure P in the circuit operation of the present invention.

FIG. 4 is a graph showing the A / D conversion value Dc with respect to the pressure P in the circuit operation of the present invention.

FIG. 5 is a resistance selection circuit diagram for offset adjustment of the present invention.

FIG. 6 is a circuit configuration diagram of a conventional example.

[Explanation of symbols]

 1 pressure sensor 2 sensor drive circuit 3 amplification circuit 4 A / D conversion circuit 6 display device 50 sensor information data processing circuit

Claims (1)

[Claims] 1. A semiconductor pressure sensor for detecting an external water pressure, a sensor drive circuit for driving the semiconductor pressure sensor, an amplifier circuit for amplifying an output voltage from the semiconductor pressure sensor, and an offset voltage of the amplifier circuit. A resistance selection circuit for adjusting the voltage, an A / D conversion circuit for A / D converting the amplified voltage of the amplification circuit at a constant cycle, and two different A / D conversion data from the A / D conversion circuit. A first arithmetic unit having a first memory and a second memory for storing, and calculating a sensor characteristic formula for outputting water depth data based on the data stored in the two memories; A sensor information data processing circuit having a second arithmetic means for converting A / D converted data from the A / D conversion circuit into water depth data according to a sensor characteristic formula, and display means for displaying the water depth data. In an electronic timepiece equipped with a water depth meter, one of the data stored in the first memory or the second memory and A / D conversion data at the same pressure as when the data in the memory is stored are compared. An electronic timepiece equipped with a water depth gauge, wherein the comparison data is displayed on the display means.