JP6883239B2 - Detection device - Google Patents

Description

The present invention relates to a detection device that detects a displacement amount of a detection target.

Conventionally, a detection device that detects a displacement amount such as a rotation amount or a movement amount of a detection target has been used. Some of these detection devices not only output the detection result but also have a function of notifying the abnormality of the wiring (for example, Patent Documents 1 and 2).

The position detection device described in Patent Document 1 is configured to include a first integrated circuit and a second integrated circuit in order to improve the reliability of the detection result, and further output each of the first integrated circuit and the second integrated circuit. It is configured so that short circuits between terminals can be detected. The first integrated circuit is a first linear voltage output circuit that outputs a voltage that linearly increases according to the position of the object to be detected, a first protection resistor whose one end is connected to the first linear voltage output circuit, and one end that is first. A first output terminal connected to the other end side of the protection resistor and the other end connected to the electronic control device, and a first abnormality detection circuit that outputs a first abnormality detection signal based on the voltage difference on both sides of the first protection resistor. Have. The second integrated circuit is a second linear voltage output circuit that outputs a voltage that decreases linearly according to the position of the object to be detected, a second protection resistor whose one end is connected to the second linear voltage output circuit, and one end. The second output terminal connected to the other end side of the second protection resistor and the other end connected to the electronic control device, and the second abnormality detection that outputs the second abnormality detection signal based on the voltage difference on both sides of the second protection resistor. It has a circuit.

The detection device described in Patent Document 2 is configured to be able to detect a disconnection of a ground harness or a power harness that connects the detection device and the processing device. The detection device includes a detection unit that outputs a detection signal according to the detected physical quantity, an output circuit that converts a control signal according to the signal value of the detection signal output from the detection unit into a current, and outputs the signal output terminal. A feedback circuit that feeds back the output voltage that is the output voltage output from the signal output terminal and is determined by the voltage drop that occurs in the external load resistance via the feedback resistor, and the detection signal that is output from the detection unit. It is configured to include a negative feedback control circuit that generates and outputs a control signal to be input to the output circuit based on the signal value of the above and the voltage value of the feedback voltage fed back from the feedback circuit. The resistance value of the feedback resistor is such that the current value of the current flowing through the signal output terminal when the ground harness or power supply harness is disconnected is less than the lower limit of the current flowing through the signal output terminal when the ground harness or power supply harness is normal. Is set to.

Japanese Unexamined Patent Publication No. 2013-1330513 Japanese Unexamined Patent Publication No. 2016-70835

The position detection device described in Patent Document 1 is provided with a protection resistor and an abnormality detection circuit on each output side of the first linear voltage output circuit and the second linear voltage output circuit, and the current flowing through the protection resistor is generated by the abnormality detection circuit. It is configured to detect whether or not it is abnormal. As described above, the position detection device described in Patent Document 1 requires a protection resistor and an abnormality detection circuit in addition to the first linear voltage output circuit and the second linear voltage output circuit in order to detect a short-circuit abnormality between the output terminals. Therefore, the size of the detection device becomes large, which causes an increase in cost. Further, when a large current does not flow through the protection resistor, a short circuit between the output terminals cannot be detected.

The detection device described in Patent Document 2 is configured to include a pull-down resistor or a pull-up resistor at the signal output terminal of the detection device. However, when the signal output terminal of the detection device is provided with a pull-down resistor, the ground harness It is not possible to detect an abnormality in the decrease in power supply potential difference due to an increase in internal resistance. This is because when the internal resistance of the ground harness increases, a potential difference occurs in the ground harness, the output voltage of the detection device input to the processing device becomes large, and it cannot be determined as a normal output, and an abnormality cannot be detected. On the other hand, when the signal output terminal of the detection device is provided with a pull-up resistor, it is not possible to detect an abnormality in which the power supply potential difference decreases due to an increase in the internal resistance of the power supply harness. This is because when the internal resistance of the power harness increases, a potential difference occurs in the power harness, the output voltage of the detection device input to the processing device becomes small, and it cannot be determined as a normal output, and an abnormality cannot be detected. In addition, when two sets of the same detection device are provided and a pull-down resistor is connected to the signal output terminal with a dual detection device that shares the power supply terminal and the ground terminal, the power supply potential difference due to the increase in the internal resistance of the ground harness. Unable to detect the decrease abnormality of. When the power supply terminal and the ground terminal are connected in common and a pull-down resistor is connected to the signal output terminal, when the internal resistance of the ground harness increases, a potential difference occurs in the ground harness and the output of the detection device input to the processing device. This is because the voltage becomes large and cannot be distinguished from the normal output, and an abnormality cannot be detected.

Therefore, there is a demand for a detection device that detects a displacement amount of a detection target and can detect an abnormality in a power supply line and a ground line at low cost.

The characteristic configuration of the detection device according to the present invention is the first detection unit that outputs a first signal in which the voltage value gradually increases as the displacement amount of the detection target increases, and the detection device according to the increase in the displacement amount of the detection target. The power supply voltage is supplied to the second detection unit that outputs the second signal whose voltage value gradually decreases, the first detection unit, and the second detection unit, and based on the first signal and the second signal. , A pull-down resistor provided between the signal processing unit that calculates the displacement amount of the detection target, the output terminal of the first detection unit, the first signal line connecting the signal processing unit, and the grounded ground line. A resistance value different from the resistance value of the pull-down resistor is provided between the output terminal of the second detection unit and the second signal line connecting the signal processing unit and the power supply line to which the power supply voltage is applied. a pull-up resistor Ru Oh, a detection device Ru provided with, if the power supply voltage value of the power supply voltage is within a predetermined range, the first detector and the second detector, respectively, The first signal and the second signal are output so that the sum of the voltage value of the first signal and the voltage value of the second signal becomes a preset constant value, and the power supply voltage value is set in advance. When the value is less than the lower limit of the specified range, the first detection unit outputs the voltage value at zero potential as the first signal, and the second detection unit outputs the voltage value of the power supply voltage. and it outputs a second signal if the sum of the voltage value of the voltage value and the second signal of the first signal is Tsu Do different voltage value with a preset voltage value is determined to be abnormal At the point.

With such a characteristic configuration, when the internal resistance of the power supply line that supplies the power supply voltage increases, or when the internal resistance of the ground line that applies the ground potential increases, the voltage value of the first signal and the second signal It is possible to prevent the sum of the signal with the voltage value from becoming the above-mentioned preset constant value. Therefore, by comparing the sum of the voltage value of the first signal and the voltage value of the second signal with the preset constant value, it is possible to detect an increase in the internal resistance of the power supply line and the ground line. .. Further, when the internal resistance of the power supply line increases, the power supply voltage value decreases, so that the voltage value of the second signal decreases together with the power supply voltage value, and the voltage value of the first signal and the voltage value of the second signal become The sum decreases. On the other hand, when the internal resistance of the ground line increases, the ground potential rises, so the voltage value of the first signal rises with the ground potential, and the sum of the voltage value of the first signal and the voltage value of the second signal also increases. To rise. Therefore, if the sum of the voltage value of the first signal and the voltage value of the second signal does not become the preset constant value, the sum of the voltage value of the first signal and the voltage value of the second signal decreases. By identifying whether the voltage is rising or rising, it is possible to identify whether the internal resistance of the power supply line is increasing or the internal resistance of the ground line is increasing. In this way, according to this detection device, it is possible to detect an abnormality in the power supply line or the ground line.

Further, as described above, the detection device outputs the first signal whose voltage value gradually increases as the displacement amount of the detection target increases, and the second signal is the displacement amount of the detection target. A second signal is output in which the voltage value gradually decreases as the voltage increases. Further, when the power supply voltage value of the power supply voltage is within the preset range, the sum of the voltage value of the first signal and the voltage value of the second signal is calculated in the first detection unit and the second detection unit, respectively. The first signal and the second signal are output so as to have a preset constant value. Therefore, depending on the displacement amount of the detection target, the voltage value of the first signal and the voltage value of the second signal may be the same value (for example, 1/2 of the power supply voltage). On the other hand, when the first signal line and the second signal line are short-circuited, the voltage value of the first signal and the voltage value of the second signal divide the power supply voltage by the resistance ratio of the pull-up resistor and the pull-down resistor. Therefore, if the pull-up resistor and the pull-down resistor have the same resistance value, both the first signal and the second signal are halved of the power supply voltage value, and is the detection device normal? It is not easy to distinguish whether it is abnormal or not. However, with the above configuration, when the first signal line and the second signal line are short-circuited, the voltage value of the first signal and the voltage value of the second signal are not halved of the power supply voltage value. The sum of the voltage values of the first signal and the voltage values of the second signal causes the first signal line and the second signal line to be short-circuited when the power supply voltage value of the power supply voltage is within a preset range. It becomes possible to easily identify whether or not it is.

It is a circuit diagram of a detection device. This is the output characteristic during normal operation. This is the output characteristic when the output terminals are short-circuited. This is the output characteristic when the internal resistance of the power supply line increases. This is the output characteristic when the internal resistance of the ground line increases.

The detection device according to the present invention is configured to have a function of detecting an abnormality occurring in a cable while detecting a displacement amount of a detection target. Hereinafter, the detection device 1 of the present embodiment will be described.

FIG. 1 is a circuit diagram schematically showing the configuration of the detection device 1. In the present embodiment, the detection device 1 includes a detection unit 10 and an electronic control unit 20, and the detection unit 10 and the electronic control unit 20 are connected by four cables 30. The detection unit 10 includes a first detection unit 11 and a second detection unit 12, and the electronic control unit 20 includes a signal processing unit 21.

The first detection unit 11 outputs a first signal in which the voltage value gradually increases as the displacement amount of the detection target increases. For example, when the first detection unit 11 is a rotation sensor, the detection target corresponds to the rotation amount, and when the first detection unit 11 is a load sensor, the detection target corresponds to the load. The detection target of the first detection unit 11 is not particularly limited, but the first detection unit 11 outputs a first signal whose voltage value gradually increases in proportion to the displacement amount of the detection target.

The second detection unit 12 outputs a second signal in which the voltage value gradually decreases as the displacement amount of the detection target increases. The second detection unit 12 detects the same displacement amount of the detection target as the first detection unit 11. However, the second detection unit 12 is different from the first detection unit 11 in that it outputs a second signal whose voltage value gradually decreases in proportion to the displacement amount of the detection target. In this way, the first detection unit 11 and the second detection unit 12 output proportional linear voltages having different slopes with respect to the same amount of displacement of the detection target.

The signal processing unit 21 supplies a power supply voltage to the first detection unit 11 and the second detection unit 12, and calculates the displacement amount of the detection target based on the first signal and the second signal. As shown in FIG. 1, the power output terminal 22 of the electronic control unit 20 and the power input terminal 13 of the detection unit 10 are electrically connected by the first cable 31, and the ground terminal 23 of the electronic control unit 20 and the detection unit 20 are detected. The ground terminal 14 of the unit 10 is electrically connected by the second cable 32. The VDD1 terminal of the first detection unit 11 and the VDD2 terminal of the second detection unit 12 are connected to the power input terminal 13, whereby the power supply voltage is supplied from the signal processing unit 21 to the first detection unit 11 and the second detection unit 12. (For example, 5V) is supplied.

Further, the first signal terminal 24 of the electronic control unit 20 and the first signal output terminal 15 of the detection unit 10 connected to the OUT1 terminal of the first detection unit 11 are electrically connected by the third cable 33, and electronically. The second signal terminal 25 of the control unit 20 and the second signal output terminal 16 of the detection unit 10 connected to the OUT2 terminal of the second detection unit 12 are electrically connected by the fourth cable 34. As a result, the first signal and the second signal are input from the first detection unit 11 and the second detection unit 12 to the signal processing unit 21, and the signal processing unit 21 is predetermined based on these signals (first signal and second signal). It is possible to calculate the amount of displacement of the detection target by performing the signal processing of.

In the detection unit 10, a capacitor CV is provided over the power supply line connected to the power input terminal 13 and the grounding line connected to the grounding terminal 14, and the signal line connected to the first signal output terminal 15. A capacitor CO1 is provided over the ground line, and a capacitor CO2 is provided over the signal line connected to the second signal output terminal 16 and the ground line. Further, in the electronic control unit 20, a capacitor C2 is provided over the signal line connected to the first signal terminal 24 and the ground line connected to the ground terminal 23, and the signal connected to the second signal terminal 25. A capacitor C1 is provided over the line and the grounding line connected to the grounding terminal 23. This makes it possible to smooth the power supply voltage and the signal transmitted by the power supply line and the signal line.

The pull-down resistor RD is provided between the first signal line connecting the output terminal of the first detection unit 11 and the signal processing unit 21 and the grounded ground line. The output terminal of the first detection unit 11 is the OUT1 terminal of the first detection unit 11. The first signal line is a line through which the first signal is transmitted. Therefore, the pull-down resistor RD is provided over the line through which the first signal connecting the OUT1 terminal and the signal processing unit 21 is transmitted and the grounding line. In this embodiment, the pull-down resistor RD is provided in the electronic control unit 20.

The pull-up resistor RU is provided between the second signal line connecting the output terminal of the second detection unit 12 and the signal processing unit 21 and the power supply line to which the power supply voltage is applied. The output terminal of the second detection unit 12 is an OUT2 terminal of the second detection unit 12. The second signal line is a line through which the second signal is transmitted. Therefore, the pull-up resistor RU is provided over the line through which the second signal connecting the OUT2 terminal and the signal processing unit 21 is transmitted and the power supply line. In this embodiment, the pull-up resistor RU is provided in the electronic control unit 20.

Next, the output characteristics of the detection device 1 will be described. FIG. 2 shows the output characteristics of the first detection unit 11 and the second detection unit 12 when the power supply voltage value of the power supply voltage is within a preset range. “The power supply voltage value of the power supply voltage is within a preset range” is the voltage value of the power supply voltage supplied from the signal processing unit 21, and this voltage value is the first detection unit 11 and the second detection unit 11. Reference numeral 12 denotes a voltage range in which the displacement amount of the detection target can be appropriately detected and the detection result can be output. In this case, as described above, in the first signal output by the first detection unit 11, the voltage value of the output voltage gradually increases as the displacement amount of the detection target increases, and the second detection unit 12 outputs the first signal. In the second signal to be output, the voltage value of the output voltage gradually decreases as the displacement amount of the detection target increases. In this way, the output characteristics of the first detection unit 11 and the second detection unit 12 are set so as to have a cross characteristic that changes in opposite directions with respect to the displacement amount of the detection target.

Further, when the power supply voltage value of the power supply voltage is within the preset range, the first detection unit 11 and the second detection unit 12 respectively have the voltage value of the first signal and the voltage value of the second signal. The first signal and the second signal are output so that the sum of the above becomes a preset constant value.

In the present embodiment, the resistance value of the pull-up resistor RU and the resistance value of the pull-down resistor RD are set to different values. Therefore, if the third cable 33 and the fourth cable 34 are short-circuited, as shown in FIG. 3, the voltage value of the first signal and the voltage value of the second signal are the power supply voltage of the power supply voltage. The value is divided by the resistance ratio between the resistance value of the pull-up resistance RU and the resistance value of the pull-down resistance RD. Further, in this case, the sum of the voltage value of the first signal and the voltage value of the second signal is a value different from the preset constant value shown in FIG. 2 (at least a value larger than the constant value). , Or a small value). Therefore, the signal processing unit 21 to which the first signal and the second signal are transmitted can identify that the third cable 33 and the fourth cable 34 are in a short-circuited state.

As described above, in the present detection device 1, it is possible to identify whether or not the third cable 33 and the fourth cable 34 are short-circuited only by providing the pull-up resistor RU and the pull-down resistor RD, and the protection resistor in the electronic control unit 20. And an abnormality detection circuit can be eliminated. Therefore, the detection device 1 can be made compact and the cost can be reduced.

On the other hand, if the first cable 31 or the second cable 32 is disconnected or is in a state close to the disconnection, the internal resistance of the first cable 31 or the second cable 32 increases. In this case, the power supply voltage value of the power supply voltage supplied to the first detection unit 11 and the second detection unit 12 is less than the lower limit value in the preset range. Therefore, the first detection unit 11 and the second detection unit 12 cannot appropriately detect the displacement amount of the detection target and output the detection result. In this way, when the power supply voltage value of the power supply voltage becomes less than the lower limit value of the preset range, the first detection unit 11 immediately outputs the first signal of the voltage value equal to or less than the predetermined value, and the second The detection unit 12 is configured to immediately output a second signal in which the sum of the voltage value of the first signal and the voltage value of the second signal is a voltage value different from the above-mentioned constant value.

FIG. 4 shows the output characteristics of the first detection unit 11 and the second detection unit 12 when the internal resistance of the first cable 31 increases. In the present embodiment, as shown in FIG. 4, when the power supply voltage value of the power supply voltage is less than the lower limit value of the preset range (for example, 4V), the first detection unit 11 and the second detection unit 11 12 enters the voltage reduction detection mode, the first signal immediately becomes the zero potential (fixed value of LOW), and the second signal becomes the power supply potential (fixed value of HIGH). At this time, since the power supply potential decreases as the internal resistance of the first cable 31 increases, the sum of the voltage value of the first signal and the voltage value of the second signal is always a voltage value different from the above-mentioned constant value. Become. Further, when the power supply voltage value drops (for example, 3V), the output stage (output circuit) of the first detection unit 11 and the second detection unit 12 becomes in a high resistance state. Therefore, the first signal has substantially the same potential as the ground potential, and the second signal has substantially the same potential as the power supply voltage. In this way, the signal processing unit 21 determines the internal resistance of the first cable 31 by the sum of the voltage value of the first signal and the voltage value of the second signal, and the voltage value of the first signal and the voltage value of the second signal. Can be identified as increasing.

FIG. 5 shows the output characteristics of the first detection unit 11 and the second detection unit 12 when the internal resistance of the second cable 32 increases. In the present embodiment, as shown in FIG. 5, when the power supply voltage value of the power supply voltage becomes less than the lower limit value of the preset range, the first signal immediately becomes the potential of the second cable 32, and the first signal becomes the potential of the second cable 32. The two signals are approximately the power supply potential. At this time, as the internal resistance of the second cable 32 increases, the sum of the voltage value of the first signal and the voltage value of the second signal gradually increases, and the voltage value is always different from the above-mentioned constant value. In this way, the signal processing unit 21 determines the internal resistance of the second cable 32 by the sum of the voltage value of the first signal and the voltage value of the second signal, and the voltage value of the first signal and the voltage value of the second signal. Can be identified as increasing.

As described above, the detection device 1 is set so that the first signal output from the first detection unit 11 and the second signal output from the second detection unit 12 have a cross characteristic, and the first signal has a cross characteristic. Since the sum of the voltage value and the voltage value of the second signal is set to be a constant value, if the sum of the voltage value of the first signal and the voltage value of the second signal does not become the constant value, It becomes possible to identify that the detection device 1 is abnormal. Further, in the detection unit 10, even if the power supply line and the grounding line of the first detection unit 11 and the second detection unit 12 are shared, whether or not the third cable 33 and the fourth cable 34 are short-circuited, and further. Can specify whether or not the internal resistance of the first cable 31 and the second cable 32 is increased. Therefore, the number of connector terminals and harnesses of the detection device 1 can be reduced, and the cost can be reduced.

[Other Embodiments]
In the above embodiment, the resistance value of the pull-up resistor RU and the resistance value of the pull-down resistor RD have been described as different values, but the resistance value of the pull-up resistor RU and the resistance value of the pull-down resistor RD are the same values. It may be. Even in this case, it is possible for the signal processing unit 21 to specify that the internal resistances of the first cable 31 and the second cable 32 are increasing.

In the above embodiment, the pull-down resistor RD and the pull-up resistor RU have been described as being provided inside the electronic control unit 20, but the pull-down resistor RD and the pull-up resistor RU may be provided outside the electronic control unit 20.

In the above embodiment, the rotation amount and the load are given as examples of the detection targets of the first detection unit 11 and the second detection unit 12, but if the two detection units are provided, the mounting position and the detection method are used. Regardless of this, it can be applied to detection devices of other uses and detection methods.

The present invention can be used in a detection device that detects the amount of displacement of a detection target.

1: Detection device 11: 1st detection unit 12: 2nd detection unit 21: Signal processing unit 3 3 : 3rd cable (1st signal line)
3 4 : 4th cable (2nd signal line)
RD: Pull-down resistor RU: Pull-up resistor

Claims (1)

A first detection unit that outputs a first signal whose voltage value gradually increases as the amount of displacement of the detection target increases.
A second detection unit that outputs a second signal in which the voltage value gradually decreases as the displacement amount of the detection target increases.
A signal processing unit that supplies a power supply voltage to the first detection unit and the second detection unit and calculates the displacement amount of the detection target based on the first signal and the second signal.
A pull-down resistor provided between the output terminal of the first detection unit and the first signal line connecting the signal processing unit and the grounded ground line, and
It is provided between the output terminal of the second detection unit and the second signal line connecting the signal processing unit and the power supply line to which the power supply voltage is applied , and has a resistance value different from the resistance value of the pull-down resistor. a pull-up resistor that provides a detection device Ru provided with,
When the power supply voltage value of the power supply voltage is within a preset range, the first detection unit and the second detection unit respectively have the voltage value of the first signal and the voltage value of the second signal. The first signal and the second signal are output so that the sum of the above becomes a preset constant value.
When the power supply voltage value is less than the lower limit of the preset range, the first detection unit outputs the voltage value at zero potential as the first signal, and the second detection unit outputs the voltage value at the zero potential as the first signal. The voltage value of the power supply voltage is output as the second signal, and the voltage value is output.
Wherein when the sum of the voltage value of the voltage value and the second signal of the first signal is Tsu Do different voltage value with a preset voltage value, detector for determining as abnormal.

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