JP2001133502A - Abnormality detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormality of a harness using an inexpensive means when the abnormality is generated in an inexpensive device for transmitting two kinds of signals of 'H', 'L' between plural control units through the harness. SOLUTION: This is an abnormality detector provided in a controller with the harness A for connecting a transistor 14 which is an output part of a main control unit 1 provided with a CPU 13 to an A/D converting circuit 21 of a sub-control unit 2, to detect the abnormality in the harness A. A potential dividing circuit 3 is provided to make an input voltage in the A/D converting circuit 21 brought into a voltage different from the voltage signal in response to kinds of the abnormality when the abnormality such as disconnection and short- circuiting is generated in the harness A, and an abnormality determining means is provided to determine the abnormality of the harness A based on the fact that the input voltage in the circuit 21 is a normal voltage signal or a voltage in response to the abnormality, in this abnormality detector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting device for detecting an abnormality in a harness or the like in a configuration in which two types of H and L voltage signals are transmitted between a plurality of control units via a harness.

[0002]

2. Description of the Related Art In recent years, it has become common to perform control using a control unit such as a computer such as a vehicle. In addition, in such an in-vehicle control device, a control unit that drives an actuator is sub-controlled for the purpose of simplifying assembly into the vehicle, simplifying wiring, and simplifying the configuration of the main control unit. It has been proposed to assemble with the actuator as a unit. As described above, when the control units are divided, a signal is transmitted between the control units via the harness.

[0003] As described above, when a signal is transmitted between the control units, the signal is transmitted through a harness.
H and L voltage signals are transmitted, and this voltage signal is
In general, the information is digitized by / D conversion.

FIG. 8 is a circuit diagram showing an example of the prior art as described above. In FIG. 8, reference numeral 01 denotes a main control unit, 02 denotes a sub control unit, and these control units 01 and 02 are harnesses. A1, power supply line C1, and ground line B1 are connected. Also, the main control unit 0
The CPU 1 includes a CPU 03 that executes various arithmetic processes, and a transistor 04 that outputs a signal to the harness A1 based on the processing results of the CPU 03. The sub-control unit 02 includes a harness A1.
An IC05 is provided for identifying whether the input voltage based on the signal from is “H” or “L”. The harness A1, the power line C1, and the ground line B1
Are bundled together.

[0005] Based on the above configuration, the second control unit 02 identifies whether the input voltage based on the signal from the harness A1 is "H" or "L", and executes processing based on this identification. As an example of the signal transmission via the harness A1, there is a case where the main control unit 01 sends a result of determining whether the system is normal or abnormal. That is, when the CPU 03 determines that the system is normal, the transistor 0
Since no drive signal is output to the harness A4, the harness A1 is not energized, and the "H" voltage signal is input to the IC05. For convenience, the main control unit 01
"H" output state. On the other hand, when it is determined that the system is abnormal, a harness A1 is energized by outputting a drive signal to the transistor 04, and an “L” voltage signal is input to the IC05. This is referred to as an “L” output state of the main control unit 01 for convenience.
Note that, when the “L” signal is input, the control unit 02 executes control corresponding to an abnormality such as stopping control.

[0006]

However, in the above-described prior art, even when an abnormality such as a disconnection or a short circuit occurs in the harness A1, the IC05 of the sub-control unit 02 displays "H" or "H". Since the signal "L" is input, there is a problem that it cannot be determined whether the signal is a signal based on a normal operation from the main control unit 01 or a signal due to occurrence of an abnormality.

This problem will be described in detail below. The state in which “H” is output from the main control unit 01 is a state in which the input voltage of the IC 05 is Vcc, and the state in which “L” is output from the main control unit 01 is the state in which the input voltage of the IC 05 is Is 0.

Therefore, when considering the failure mode of the harness A1, the following three modes exist. First failure: disconnection of the harness A1 Second failure: contact between the harness A1 and the harness B1 Third failure: contact between the harness A1 and the harness C1 Here, in the case of the first failure, the voltage of Vcc is directly applied to the IC 05. Therefore, the input voltage becomes “H”. In the case of the second failure, the harness A
1 is grounded and the input voltage of IC05 is 0, that is, "L".
Becomes In the case of the third failure, the battery voltage is applied as it is, and the input voltage of the IC 05 becomes “H”.

As described above, even when an abnormality occurs in the harness A1, "H" and "L" signals having the same voltage as the normal voltage signal from the main control unit 01 are output from the IC0.
5, the IC05 has a problem that it is not possible to identify whether a normal signal is input from the control unit 01 or whether an abnormality has occurred.

In order to solve the above-mentioned problem, a signal is wirelessly transmitted between the two control units so that a short circuit of the wiring does not occur, or between the two control units. To perform a data communication to exchange a signal completely different from a signal generated when a failure such as a short circuit occurs, or to transmit two types of analog voltage signals which are intermediate voltages between a power supply voltage and 0 VT. In this case as well, it is conceivable to make the signal different between the time of failure and the time of normality. However, in any of these configurations, there is a problem that the cost is significantly increased.

The present invention has been made in view of the above-mentioned conventional problems, and is inexpensive for transmitting two types of signals "H" and "L" between a plurality of control units via a harness. It is an object of the present invention to achieve, when an abnormality occurs in a harness, detection of the abnormality by an inexpensive means.

[0012]

In order to achieve the above object, the present invention provides a first control unit having control means and a first control unit having an A / D conversion circuit. Abnormality detection that is provided in a control device including: a control unit; and a harness that connects an output unit of the first control unit and an A / D conversion circuit of the second control unit. An apparatus, wherein when an abnormality such as disconnection or short circuit occurs in the harness, an input voltage in an A / D conversion circuit differs from the voltage signal in accordance with a type of abnormality such as connection to a power supply side or a ground side. A voltage dividing circuit for providing a voltage is provided, based on whether the input voltage in the A / D conversion circuit is a normal voltage signal or a voltage corresponding to an abnormality. Wherein the abnormality determining means for determining abnormality of the harness are provided.

According to a second aspect of the present invention, the voltage dividing circuit is provided in the first control unit,
A first resistor connected in series between the collector of the transistor that outputs the voltage signal and the harness, and one connected between the first resistor and the harness and the other grounded A second resistor, provided in the second control unit, and connected to the harness and A / D
A third resistor provided in series with the conversion circuit, and a fourth resistor one of which is connected in the middle of a circuit connecting the third resistor and the A / D converter and the other of which is connected to a power supply. , And is characterized by the following.

[0014]

According to the first aspect of the present invention, when an abnormality such as a disconnection or a short circuit occurs in the harness connecting the first control unit and the second control unit, the second control unit is connected to the first control unit. An input voltage different from the “H” and “L” voltage signals is input to the A / D conversion circuit.

Therefore, when there is an input voltage different from the voltage value of the normal voltage signal,
An abnormality can be determined based on the voltage value.

As described above, according to the first aspect of the present invention, only the voltage dividing circuit is connected to the harness, and the output signal from the first control unit is "H".
The advantage is that the abnormality of the harness can be detected by a simple and inexpensive configuration that outputs a simple signal of “L”.

According to the second aspect of the present invention, when no abnormality occurs in the harness, the transistor of the first control unit is driven, that is, in a state where "L" is output to the A / D conversion circuit. , The first to third resistors are connected in parallel to the fourth resistor, and the voltage based on the connection of the first to fourth resistors is a voltage of “L”. The signal is input to the A / D conversion circuit. On the other hand, in a state in which the transistor is not driven, that is, in a state in which “H” is output to the A / D conversion circuit, in the voltage dividing circuit, the second resistor and the third resistor are connected in parallel with the fourth resistor.
A resistor is connected, and the voltage based on the connection of the second to fourth resistors is A / D as a voltage signal of “H”.
Input to the conversion circuit.

Next, a case where an abnormality occurs in the harness will be described. First, in the case of a first failure in which the harness is broken, the first to third resistances are opened, and a voltage on the power supply side determined by the resistance of the fourth resistance is input to the A / D conversion circuit. Therefore, a voltage different from that when the harness is normal is input to the A / D conversion circuit.

Next, in the case of the second fault in which the harness is grounded, the third resistor is connected in parallel to the fourth resistor in the voltage dividing circuit, and the third resistor is connected to the A / D conversion circuit. A voltage based on the connection of the fourth resistor is input. Therefore, A / D
A voltage different from that at the time of normal harness and at the time of the first failure is input to the conversion circuit.

Next, in the case of a third failure in which the harness is short-circuited to the power supply side, the third resistance is connected in parallel to the fourth resistance, and each resistance is connected to a different power supply, and A /
The resistance values of the third resistor and the fourth resistor and a voltage determined by each voltage are input to the D conversion circuit. Therefore, the A / D conversion circuit includes the first harness and the first harness.
-A voltage different from that at the time of the second failure is input.

As described above, according to the second aspect of the present invention, a simple configuration in which the voltage dividing circuit including the first to fourth resistors is provided enables the A to respond to each abnormality such as disconnection or short circuit of the harness. The voltage input to the / D conversion circuit can be made different, and the type of abnormality can be reliably determined based on this.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 1 is a configuration diagram of an in-vehicle system to which an abnormality detection device according to an embodiment is applied. In the figure, 1 is a main control unit corresponding to a first control unit in the claims, and 2 is a second control unit in the claims.
A sub-control unit corresponding to the control unit, both of which are connected by a harness A, so that a signal is transmitted from the main control unit 1 to the sub-control unit 2. An example of such a system is, for example, a vehicle brake fluid pressure control device. In such a brake fluid pressure control device, a brake unit (not shown) mounted in an engine room is assembled with a sub-control unit 2 for driving an electromagnetic valve in the unit. And the main control unit 1 mounted on the vehicle is configured to transmit a signal via a harness A. In the present embodiment, the harness A
Together with the power supply line C and the ground line B.

The main control unit 1 includes:
A CPU 13 corresponding to the control means in the claims is provided, and a transistor 14 is connected to an output port of the CPU 13.
Is connected. This transistor 14 is connected to the CPU 1
When a drive signal is input from the output port of No. 3, energization is stopped in the harness A, and when no drive signal is input, energization is not performed in the harness A.

The sub-control unit 2 includes:
A / D for A / D conversion of the signal input from harness A
A D conversion circuit 21 is provided. By the way, when the transistor 14 is driven and the harness A is energized, an "L" voltage signal is input to the A / D conversion circuit 21. When the transistor 14 is not driven and the harness A is not energized, the A / D The “H” voltage signal is input to the D conversion circuit 21.

A voltage dividing circuit 3 according to the present invention is provided between the transistor 14 of the main control unit 1 and the harness A and between the A / D conversion circuit 21 of the sub control unit 2 and the harness A. , A first voltage dividing circuit 31 and a second voltage dividing circuit 32 are provided.

The first voltage dividing circuit 31 includes a first resistor 31 provided in series between the harness A and the transistor 14.
a and a second resistor 31b connected to the ground in parallel with the first resistor 31a.

On the other hand, the second voltage dividing circuit 32 includes a third resistor 32a provided in series between the harness A and the A / D conversion circuit 21, and a power supply circuit connected in parallel with the third resistor 32a. And a fourth resistor 32b connected to Vcc.

The CPU 13 includes the A / D conversion circuit 2
As a control for outputting two kinds of voltage signals of “H” and “L” for one, a system abnormality determination process (different from the harness abnormality determination in the claims) is executed. That is,
It is determined whether or not the system is normal based on a predetermined input. If it is determined that the system is normal, a drive signal is output from the output port of the CPU 13 to the transistor 14 to output the A / D signal.
The conversion circuit 21 is configured to input a voltage signal of “L”. On the other hand, when the system determines that the system is abnormal,
A drive signal is not output from the output port of PU13, and A / D
The conversion circuit 21 performs a process for inputting the “H” voltage signal.

Here, the resistance value of the first resistor 31a is R1,
When the resistance value of the second resistor 31b is R2, the resistance value of the third resistor 32a is R3, and the resistance value of the fourth resistor 32b is R4, when the drive signal is output from the output port of the CPU 13, ie, the sub control unit The input voltage Vad when the voltage of “L” is input to the A / D conversion circuit 21 of FIG. 2 can be represented by the equivalent circuit shown in FIG. 2. Therefore, the input voltage Vad at this time is ,
It can be obtained by the following equation. Vad = Vcc- ｛R4 × (R2 + R1) × Vcc-R
4 × R2 × Vce｝ / ｛(R2 + R1) (R4 + R3 +
R2) -R22} In the expression, Vce is a voltage of the transistor 14.

On the other hand, when no drive signal is output from the output port of the CPU 13, that is, when the "H" voltage is input to the A / D conversion circuit 21, the input voltage Vad can be represented by the equivalent circuit of FIG. Therefore, the input voltage Vad at this time can be obtained by the following equation.

Vad = ｛(R2 + R3) / (R4 + R3
+ R2)｝ × Vcc.

Next, the input voltage Vad of the A / D conversion circuit 21 in the first to third faults described in the prior art.
Ask for. (First Failure) First, in the case of the first failure in which the harness A is disconnected, the input voltage Vad in the A / D conversion circuit 21 can be represented by an equivalent circuit shown in FIG. Therefore, the input voltage Vad is represented by the following equation. Vad = Vcc (Second Failure 2) Next, in the case of the second failure in which the harness A and the ground line B are in contact, the input voltage Vad in the A / D conversion circuit 21 can be represented by an equivalent circuit shown in FIG. it can. Therefore, the input voltage Vad is represented by the following equation.

Vad = {R3 / (R4 + R3)} × Vcc (Third Failure) Next, in the case of the third failure in which the harness A and the power supply line C are in contact, the input voltage Vad in the A / D conversion circuit 21 is It can be represented by the equivalent circuit shown in FIG. Therefore, the input voltage Vad is represented by the following equation.

Vad = ｛(R4 × Vbatt) + (R3
× Vcc)｝ / (R4 + R3) As described above, by providing the voltage dividing circuit 3, the A / D
"H" based on the processing result of the CPU 13 is given to the conversion circuit 21.
The input voltage Vad in the A / D conversion circuit 21 can be made different between when the "L" signal is input and when the first to third failures occur.

For example, in this embodiment, Vcc = 5.
0 (V), Vce = 0.5 (V), Vbatt = 10
16 (V), R4 = 10 (kΩ), R3 = 10 (k
Ω), R2 = 10 (kΩ), and R1 = 5.1 (kΩ), the input voltage Vad has the following value. Normal (“H” output) → 3.0002833V Abnormal (“L” output) → 3.3333333V 1st fault → 5.0V 2nd fault → 2.5V 3rd fault → 7.5V However, 3rd fault In this case, since the input of the A / D conversion circuit 21 is up to 5 V in this embodiment, it is assumed that the input is recognized as 5 V. Therefore, in the present embodiment, A /
The input voltage Vad of the D conversion circuit 21 has a magnitude relationship of third failure = first failure> abnormal (at the time of “L” output)> normal (at the time of “H” output)> second failure.

On the basis of the magnitude relationship of the input voltage Vad, the sub-control unit 2 executes the failure judgment control described below by means of abnormality judgment means (not shown). FIG. 7 is a flowchart showing the flow of the failure determination control. In step 101, the A / D conversion circuit 21 performs A / D conversion to obtain an input voltage Vad. In step 102, the input voltage Vad is set to 4.1.
(V), it is determined whether or not Vad> 4.1.
In the case of (V), it is determined that the failure is the first failure or the third failure as shown in step 105, while Vad ≦
In the case of 4.1 (V), the process proceeds to step 103.

In step 103, Vad> 3.15
(V), and if Vad> 3.15 (V), it is determined that the system is abnormal as shown in step 106, while if Vad ≦ 3.15 (V), step 104 Proceed to.

In step 104, Vad> 2.75
(V) is determined, and if Vad> 2.75 (V), the system is determined to be normal as shown in step 107. On the other hand, if Vad ≦ 2.75 (V), the step is performed. As shown at 108, it is determined that the second failure has occurred. The part for performing the failure determination shown in FIG. 7 corresponds to the abnormality determination means in the claims.

As described above, in this embodiment, when a failure occurs in the harness A in the voltage dividing circuit 3, the input voltage Va in the A / D conversion circuit 21 depends on the situation of the failure.
Since d is configured to have a different value from that when the harness is normal, the failure state can be accurately determined. In the present embodiment, making the input voltage Vad different depending on the failure state in this way simply means that the plurality of resistors 3
This is achieved by providing the voltage dividing circuit 3 having a simple configuration having only 1a, 31b, 32a, and 32b. When an abnormality occurs in A, the effect of being able to detect the abnormality can be achieved by inexpensive means.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present invention. Even if present, it is included in the present invention. For example, in the embodiment, the first control unit and the second control unit
As a control unit, a control unit that has a relationship of main and sub is shown, but if one example is shown,
The present invention is also applicable to a configuration in which control units in a parallel relationship such as a brake control unit and an engine control unit are connected by a harness. Further, the signal output from the CPU of the first control unit to the second control unit is not limited to a signal indicating a system abnormality as described in the embodiment.

[Brief description of the drawings]

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

FIG. 2 is an equivalent circuit diagram when a normal voltage signal according to the embodiment is output.

FIG. 3 is an equivalent circuit diagram when a normal voltage signal according to the embodiment is output.

FIG. 4 is an equivalent circuit diagram in the case of a harness disconnection in the embodiment.

FIG. 5 is an equivalent circuit diagram when a harness and a ground line are in contact in the embodiment.

FIG. 6 is an equivalent circuit diagram when a harness and a power supply line are in contact in the embodiment.

FIG. 7 is a flowchart showing a flow of detecting a harness abnormality in the embodiment.

FIG. 8 is a circuit configuration diagram showing a conventional technique.

[Explanation of symbols]

Reference Signs List A Harness B Ground line C Power line 1 Main control unit (first control unit) 13 CPU 14 Transistor 2 Sub-control unit (second control unit) 21 A / D conversion circuit 3 Voltage dividing circuit 31 First voltage dividing circuit 31a 1 resistance 31b second resistance 32 second voltage dividing circuit 32a third resistance 32b fourth resistance

Claims (2)

[Claims] A first control unit including a control unit; a second control unit including an A / D conversion circuit; an output unit of the first control unit; and an A / D conversion circuit of the second control unit. An abnormality detection device provided in a control device including: a power supply side or a ground side when an abnormality such as a disconnection or a short circuit occurs in the harness. A voltage dividing circuit that sets an input voltage of the A / D conversion circuit to a voltage different from the voltage signal in accordance with a type of abnormality such as connection with the voltage signal; An abnormality determining means for determining an abnormality of the harness based on the voltage corresponding to the abnormality. Detection device. A second resistor provided in the first control unit and connected in series between a collector of a transistor for outputting the voltage signal and the harness; A second resistor, one of which is connected between the first resistor and the harness and the other grounded, provided in the second control unit, and connected in series between the harness and the A / D conversion circuit; And a fourth resistor, one of which is connected in the middle of a circuit connecting the third resistor and the A / D converter, and the other of which is connected to a power supply. The abnormality detection device according to claim 1, wherein: