JPS61180121A - Force detecting device - Google Patents

Abstract

PURPOSE:To detect an abnormal state such as the breaking of a conductor automatically, easily, and distinctively from the alarm of a saturation area by providing the 1st - the 3rd resistors, etc. CONSTITUTION:The 1st resistor R1, the 2nd resistor R2, the 3rd resistor R3, etc., are provided. Then, the resistor R1 is connected between a terminal 2b and a positive potential line 6 so that the positive potential of a driving power source which drives an operational amplifier 2 is supplied to the positive power source terminal 2b of the amplifier 2. The resistor R2, on the other hand, is connected between the line 6 and the output terminal 2 of a device and the resistor R3 is connected between the terminal 3 and a reference potential line 5. Further, the driving power source is incorporated in a signal processing part 10 and when an abnormal state such as the breaking of a wire, etc., occurs in conductors 3a, 7a, and 8a, lines 5 and 6, etc., a pressure monitoring device 15 outputs an upper or lower side abnormal voltage from the terminal 3 by a mechanism provided to a pressure detecting device 14; and a processing part 10 detects this abnormal voltage and outputs an alarm signal.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a method for detecting force such as pressure using a diffused silicon semiconductor strain sensor, which is supplied with power from a signal processing section and sends an output signal to the signal processing section. The present invention relates to a device, and particularly to a device configuration that facilitates automatic detection of an abnormal state such as a disconnection in a conductive wire connecting the force detection device and a signal processing unit.

C. Prior art and its problems] Figure 3 is a block diagram of a pressure monitoring device for an automobile engine using a conventional pressure detection device. Pressure sensor configured using strain resistance element, 2
is an operational amplifier to which the output voltage E of the pressure sensor 1 output according to the applied pressure is input, and R3 is connected between the output terminal 3 of this pressure detection device and the output side terminal 2a of the operational amplifier 2. R4 is a differential amplifier consisting of the amplifier 2, the fifth resistor R1, and the main resistor R4, which feeds back the potential of the output terminal 3 to the inverting input terminal Iζ of the operational amplifier 2. 4 feedback resistor. For example, when an abnormal condition occurs such as when the output terminal 3 comes into contact with the reference potential line 5 of the drive power source of the operational amplifier 2, an overcurrent flows through the output circuit of the operational amplifier 2 and It has an operational amplifier protection function to prevent the amplifier 2 from being destroyed and a function to prevent oscillation of the differential amplifier 4, and the resistance value of the feedback resistor also controls the amplification degree of the differential amplifier 4. In this case, the positive power terminal 2b is connected to the positive potential line 6 of the driving power source, and the reference power terminal 2C is connected to the reference potential line 5. 7 and 8 are potential lines 5, respectively.
, 61ζ are power supply terminals for supplying a predetermined potential, and 9 is a pressure detection device consisting of the above-mentioned parts. Since the pressure detection device 9 is configured as described above, a signal corresponding to the pressure detected by the pressure receiving sensor 1 appears at the device output terminal 3 as an output terminal of the differential amplifier 4. 10 is a signal processing unit that supplies the above-mentioned operational amplifier drive power to the pressure detection device 9, receives the signal output from the detection device, and processes the signal as appropriate;
3a, 7a, 8a are the signal processing section 10 and the pressure detection bag f9
It is an electric wire that connects the

11 is a pressure monitoring device consisting of a pressure detection device 9 and a signal processing section 10. In the figure, only one pressure detection device 9 is connected to one signal processing section 10, but normally in a pressure monitoring device such as an automobile engine, one signal processing section 10 is used for detecting suction negative pressure, etc. It is usual that a plurality of pressure detection devices, such as one for detecting combustion exhaust gas pressure, are connected.

FIG. 4 is an explanatory diagram of the operation of each part in the pressure monitoring device [11] shown in FIG.
1 The vertical axis indicates the voltage V output from the output terminal 3 of the pressure detection device. In FIGS. 3 and 4, a characteristic line 12 indicates the output characteristic of the pressure detection device 9 when the pressure detection device 9 is in a normal operating state, and a characteristic line 13 indicates the output characteristic of the pressure detection device 9.
The normal pressure detection range, Pu, and Pd are the maximum pressure, minimum pressure, and Vmu in the detection range 13, respectively.

V m d are output voltages corresponding to pressures Pu and Pd, respectively. The characteristic line 12 shows that when the pressure P applied to the pressure sensor 1 increases beyond the maximum pressure Pu, the output voltage V increases and finally reaches the upper limit summation voltage vh, and when the pressure P decreases beyond the minimum pressure Pd, the output voltage V increases. This shows that the voltage V decreases and finally reaches the lower limit saturation voltage Vi. FH is the upper limit fail-safe voltage region set in the signal processing unit 10 so that the lower voltage is Vfhd and the voltage width is ΔVfh, and PL is the upper limit fail-safe voltage region set so that the upper voltage is Vflu and the voltage width is ΔVfl. In the lower limit fail-safe voltage range set in the signal processing unit 10, it is set to be Vflu (Vfhd), and the signal processing unit 10 is set to be Vflu (Vfhd).
Alternatively, the alarm signal is output even if the voltage in the FL is inputted from any one of the plurality of pressure detection devices via the output terminal 3 or the like. V e h , V
e1 is the electric wire 3a in FIG.

7a, 8a, potential lines 5, 6, etc., when an abnormal state such as disconnection or mutual short circuit occurs, an upper abnormal voltage is output to the output terminal 3 by a mechanism (not shown) provided in the pressure detection bag f9. , with abnormal voltage on the lower side, normal pressure monitoring device 1
1, the related parts are configured so that the voltage Veh is in the region FH and the voltage Yet is in the region FL.

Since each part of the pressure monitoring device 11 is configured as described above, if the characteristic line 12 is in either or both of the fail-safe area FH and PL, the electric wires 3a, 7a, 8a and the potential line 5 Even if the above-mentioned abnormal condition does not occur in the ゜6 etc., the signal processing unit 1
A phenomenon occurs in which the above-mentioned alarm signal is output from □. That is, in this case, it is impossible to determine whether the pressure detection device 9 is in a normal state or an abnormal state based on the above-mentioned alarm signal.
Since the voltage width ΔVfh and the voltage width ΔVfl of the upper voltage Vflu1 are usually set unilaterally on the side of the signal processing unit 10 to which a plurality of pressure detection devices 9 are connected, the characteristic line 12
It is necessary to prevent the pressure from entering either of the fail-safe regions 1i'H and PL, but since the pressure detection device 9 is configured as described above, such a detection device t does not cause the characteristic line 12 to There is a problem in that it cannot be adjusted to prevent it from entering the region F'I(, FL).

[Purpose of the invention]

The present invention solves the conventional problems in a force detection device such as pressure using a diffusion type semiconductor strain sensor as described above, and improves the upper limit saturation voltage vh of the characteristic line 12 as shown in FIG.
By adjusting the lower limit saturation voltage Vl, it is possible to prevent the characteristic line 12 from entering either of the regions FH and FL, thereby preventing abnormalities such as disconnection of the conductor connecting the force detection device and the signal processing section. It is an object of the present invention to provide a force detection device that can automatically and easily detect a state and distinguish it from a warning that the saturation region has been entered.

[Key points of the invention]

In order to achieve the above-mentioned object, the present invention includes a differential amplifier in which the operational amplifier 1 has a fifth resistor connected to its output terminal;
and a diffused semiconductor strain sensor that inputs an output voltage to the differential amplifier. In a force detection device that detects the force applied to the semiconductor strain sensor by the output pressure of the differential amplifier, the operational amplifier is driven. A first drive power supply is supplied to the positive power supply terminal of the operational amplifier via the first resistor, and the positive potential line of the drive power supply to which the positive potential is applied is connected to the output terminal of the differential amplifier. 2 resistors; and a 3rd resistor connecting the output terminal of the differential tank 1 unit and the reference potential line of the drive power supply;
With this configuration, by adjusting the resistance values of the first to third resistors, the output voltage of the differential amplifier can be adjusted so that the output voltage falls within the above-mentioned fail-safe region FH, PL. If the output voltage of the force detection device is in the fail-safe region FH, PL, the signal processing section will issue an alarm signal. In a device such as a force monitoring device that outputs an output signal, the detection of an abnormal condition such as a disconnection of a conductor connecting the force detection device and the signal processing section can be automatically and easily distinguished from a saturation region alarm. The present invention provides a force detection device that can be operated separately.

[Embodiments of the invention]

FIG. 1 is a configuration diagram of a pressure detection device 14 which is an embodiment of the present invention. In the figure, for convenience of explanation, the pressure detection device 14 is connected to a signal processing section 106ζ, and together with the signal processing section 10, a pressure monitoring device 15 is connected. is forming. The differences between Fig. 1 and Fig. 3 are the first resistor R8, the second resistor R8, and the third resistor R.
3, in this case the first resistor R1
is connected between the terminal 2b and the positive potential line 6 so as to supply the positive potential of the drive power supply for driving the operational amplifier 2 to the positive power supply terminal 2b of the operational amplifier 2, and the second resistor R2 is connected to the positive potential line 6. connected between line 6 and device output terminal 3;
A resistor 3 is connected between the output terminal 3 and the reference potential line 5. The above drive power source is the same as in Figure 3.
The pressure monitoring device 15 is incorporated in the signal processing unit 10, and as in the case of FIG.
If an abnormal state such as disconnection or mutual short circuit occurs in the potential lines 5, 6, etc., a mechanism (not shown) provided in the pressure detection device 14 generates an upper or lower abnormal voltage similar to that shown in FIG. Veh and Vel are output from the output terminal 3, and the signal processing section 10 is configured to detect these abnormal voltages and output an alarm signal.

That is, the signal processing unit 10 has fail-safe areas FH and FL that include the respective magnitudes of the abnormal voltages Veh and Vel.
is provided.

In FIG. 1, each part is configured as described above, so the pressure detection device 14 operates in the same manner as the pressure detection device 9 in FIG. Pressure detection device 1 in this case outputs a voltage signal
The output voltage characteristic of No. 4 is as shown by the characteristic line 16 in FIG.

In FIG. 2, Vsh and Vsl are the upper limit saturation, voltage, and lower limit saturation voltage of the characteristic line 16, respectively, and since the pressure detection device 14 is configured as shown in FIG. 2) It is expressed as follows. these(
1) In equations (2), Vh and Vl are the upper and lower saturation voltages shown in FIG. 4, respectively, and flow into the operational amplifier 2 from the positive potential line 6 via the first resistor. Current, vCC is the voltage of the positive potential line 6 with respect to the reference potential line 5, and Vout is the voltage of the reference potential line 5 of the terminal 3.
4 is the voltage of the inverting input terminal potential of the operational amplifier 2 with respect to the reference potential line 5. At this time, the currents I, , I8. I, respectively, are the following (1) (2)
Chapter number ≠* expressed as the formula.

Vsh=Vh-R+"It+(It-I, -I4)@R
, 1 (1) and (2), the saturation voltages Vsh and Vsl can be appropriately set by adjusting the resistance values of the resistors R1 and R1.

Therefore, in the pressure detection device 14, by adjusting the resistors R3 and R3 in this way, the characteristic line 16 can be set in the fail-safe regions FH and FH set in the signal processing section 10.
The pressure sensing device 14, whose output voltage characteristics are set so as not to fall into either of the regions FH and FL, is
The force detecting device can easily automatically detect abnormal states such as disconnections and short circuits of wires a, 7a, 8a, etc. since they are reliably distinguished from alarms in the saturated region of the characteristic line 16.

Although the embodiment described above was a pressure detection device f14, the present invention is not limited to such a pressure detection device.
It is clear that the present invention can also be applied to a force detection device in which the configuration of the pressure sensor 1 is changed and a diffusion type semiconductor strain sensor is used to detect other types of force than pressure.

〔Effect of the invention〕

As described above, the present invention includes a differential amplifier in which the fifth resistor is connected to the output terminal of the operational amplifier, and a diffused semiconductor strain sensor that inputs an output voltage to the differential amplifier. In a force detection device that detects the force applied to a semiconductor strain sensor by the output voltage of a differential amplifier,
A positive potential of a drive power supply that drives an operational amplifier is supplied to a positive power supply terminal of the operational amplifier via a first resistor, and a positive potential line of the drive power supply to which the positive potential is applied and the output of the differential amplifier. a second resistor that connects the terminal; and a third resistor that connects the output terminal of the differential amplifier and the reference potential line of the drive power supply.
Since the resistors and; are provided, with this configuration, by adjusting the respective resistance values of the first to third resistors, the output voltage of the differential amplifier can be adjusted to the above-mentioned fail-safe condition. As a result, when the output voltage of the force detection device composed of the force detection device and the signal processing section is in the fail-safe region H or FL, a signal is generated. Automatically and easily detect abnormal conditions such as disconnection of a conductor connecting a force detection device and a signal processing section in a device such as a force monitoring device that outputs an alarm signal from a processing section. This has the effect of providing a force detection device that can distinguish between warnings in the saturated region and other areas.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an embodiment of the present invention, and Figure 2 is a diagram of Figure 1 f.
3 is a block diagram of a pressure monitoring device using a conventional pressure detection device, and FIG. 4 is an explanatory diagram of the operation of each part in FIG. 3. Power supply terminal, 3... Device output terminal as output terminal of differential amplifier, 4... Differential amplifier, 5... Reference potential line, 6... Positive potential line, 9, 14... Power Detection device and Figure 1, Figure 3

Claims (1)

[Claims] It consists of a differential amplifier in which a fifth resistor is connected to the output terminal of the operational amplifier, and a diffused semiconductor strain sensor that inputs an output voltage to the differential amplifier, and the output voltage of the differential amplifier causes the semiconductor strain sensor to In a force detection device that detects a force applied to a strain sensor, a positive potential of a drive power source that drives the operational amplifier is supplied to a positive power supply terminal of the operational amplifier via a first resistor, and the positive potential a second resistor that connects the positive potential line of the drive power supply to which is applied and the output terminal of the differential amplifier; a second resistor that connects the output terminal of the differential amplifier and the reference potential line of the drive power supply; A force detection device characterized by comprising three resistors and;