JPH083513B2 - Electronic circuit diagnosis method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing an electronic circuit, and more particularly to a method for diagnosing a bus line in which a large number of wires run in close proximity and in parallel.

[Prior art]

2. Description of the Related Art In recent years, with the miniaturization of electronic devices, miniaturization of circuit components and high-density packaging have rapidly progressed, and the incidence of troubles due to short-circuits or disconnections between terminals and bus lines is increasing. For this reason, in the conventional electronic circuit, the diagnostic process is performed on the portion before the actual process is started.

FIG. 2 is a circuit diagram showing an example of a conventionally commonly used electronic circuit diagnosis method. In the figure, 1 is for example operation control unit for executing various controls by using a microcomputer, 2 ₀ to 2 _n is the control signal output bus line sent from the output port P ₀ to P ₇ of the arithmetic and control unit 1 3 is a driver circuit that is supplied via 3, 3 ₀ to 4 ₇ are power transistors operated by the respective outputs of the driver circuits 2 ₀ to 2 ₇ , and 5 _{0 to} 5 ₇ are driven by the respective power transistors 4 ₀ to 4 ₇ . actuator as a controlled object, 6 _{0-6 7} is a buffer circuit which receives the output signal of the power transistors 4 _{0-4 7} respectively, the arithmetic control unit 1 and the output signal via the input bus lines 7 It is fed back to the input ports I _{0 to} I ₇ .

In the circuit configured as described above, when the external signal A is supplied to the input terminal IN, the arithmetic control unit 1 causes the external signal A
By calculating the required control signal for the controlled object from the output ports P _{0 to} P ₇ . This control signal is sent to the driver circuit via the output bus line 3.
It is amplified by being supplied to the 2 _{0-2 7.} Control signal amplified in the driver circuit 2 _{0-2 7,} the actuator 5 _{0-5 7} as from the turning on the power transistor corresponding supplied to the power transistor 4 _{0-4 7,} the controlled object by the output Is driven and the target control is executed.

Here, the output signal of the power transistors 4 _{0-4 7,}
Since it is fed back to the input ports I _{0 to} I ₇ of the arithmetic control unit 1 via the buffer circuits 6 _{0 to} 6 ₇ and the input bus line 7, the arithmetic control unit 1 outputs from the output ports P _{0 to} P _7. The control signal is compared with the signals fed back to the input ports I _{0 to} I ₇ . If both of these signals match, it is determined that the target control has been executed without fail, and the process proceeds to the next processing step. If a mismatch occurs between the two signals, an accident such as a short between terminals or a bus line or a break in the bus line may occur in a part of the control signal path or feedback system corresponding to this mismatch. Is determined to have occurred. When an abnormality occurs in this diagnosis result, the target accurate control cannot be performed due to an abnormality in the output system, so the operator is notified of the occurrence of the abnormality and the subsequent control is stopped. In other words, the control result is fed back, it is confirmed that the target control has been executed, and the next control is performed.

[Problems to be solved by the invention]

However, since the above-described electronic circuit diagnosis method diagnoses by comparing the feedback signal of the control signal supplied to the controlled object and the output control signal, the signal line to which the same type of control signal is supplied is used. Since it was not possible to make a diagnosis between adjacent lines in the parallel part, it could not be said to be a reliable diagnosis method.

Therefore, the present invention has been made to solve the above problems, and it is an object of the present invention to provide an electronic circuit diagnosis method capable of performing a complete diagnosis.

[Means for Solving the Problems] In the electronic circuit diagnosis method according to the present invention, in the diagnosis mode, each output port outputs a diagnosis signal having a pattern in which signals flowing in adjacent lines have different types from each other, and this diagnosis is performed. The feedback signal from the portion where the signal line of the signal exceeds the parallel portion is compared with the diagnostic signal for diagnosis.

[Action]

When such a diagnostic method is used, different types of diagnostic signals are sent to adjacent lines, so if a short circuit occurs between terminals or between lines, one line signal will always be affected by the short circuit and change. However, if a line is broken, the signal flowing through that line changes, so that a complete diagnosis can always be performed.

〔Example〕

FIG. 1 is a circuit diagram for explaining an embodiment of an electronic circuit diagnosing method according to the present invention, and the same portions as those in FIG. 2 use the same signals and detailed description thereof is omitted. In the figure, reference numeral 8 denotes a selector that is switched by a select signal output from the control port E of the arithmetic control unit 1 in the diagnostic mode, and port A is an input / output port of the arithmetic control unit 1 via the data bus line 9. Connected to IO _0- IO ₇ ,
Port B is connected to a portion of the output bus line 3 that exceeds the portion where the signal lines are parallel, and port C is a data bus line.
Connected to 10. And port A is normal port B
Is selected.

In the circuit thus configured, the arithmetic control unit 1 executes the diagnostic mode before starting the actual processing. In this diagnostic mode, the output ports P _{0 to} P ₇ generate diagnostic signals in which the signals flowing in the adjacent lines are signals of different types and are supplied to the output bus line 3. Here, as the diagnostic signal, for example, an 8-bit signal composed of "01010101" is used. Further, since the arithmetic control unit 1 generates a select signal from the control port E and supplies it to the control input terminal SE of the selector 8 in the diagnostic mode, the selector 8 changes the connection of the input port A from the port C to the port B. Are switching. Therefore, in this state, the diagnostic signal supplied to the output bus line 3 is a portion where the signal lines are parallel.
The portion beyond 31 is fed back to the input / output ports IO _{0 to} IO ₇ of the arithmetic control unit 1 via the selector 8 and the data bus line 9. The arithmetic and control unit 1 has output ports P ₀ to
The diagnostic signal sent from P ₇ and the signal returned to the input / output ports IO _{0 to} IO ₇ are compared. In addition, in the above comparison, if a part of the mismatch occurs, it is judged that the signal line corresponding to this mismatch is broken or a short-circuit accident with the adjacent signal line occurs, and the operator is notified of the detection of the abnormal part. At the same time, the transition to the next actual process is stopped.

In this case, since the diagnostic signals supplied to the output bus line 3 are set so that the types (patterns) of the signals flowing in the adjacent lines are different from each other as described above, the terminals or the lines are adjacent to each other. If a short circuit is made between the two parts, the "1" signal flowing in the line adjacent to the line that is the "0" signal flows in, so the signals flowing in the two lines in this shorted part are both "1". Becomes When the line to which the "1" signal is supplied is broken, the feedback signal changes to "0", which enables determination. However, if the line to which the "0" signal is supplied is broken, the feedback signal will also be "0" and it will not be possible to make a determination. In this case, the diagnostic signal pattern changes from "01010101" to " The problem is solved by reversing to 101010 "and diagnosing again.

In the diagnostic mode, the diagnostic signals supplied to the output ports P _{0 to} P ₇ are supplied to the controlled circuit via the output bus line 3, so the controlled circuit should be prevented from operating in the diagnostic mode. Needless to say, there is a need to do so.

[Effects of the Invention] As described above, the electronic circuit diagnosis method according to the present invention, in the diagnosis mode of the arithmetic control unit, detects the signals flowing from the control terminals arranged in parallel to the output bus line to the adjacent line. By supplying a diagnostic signal set so that the types are different from each other, by feeding back the diagnostic signal in the portion where the signal line exceeds the parallel portion to the arithmetic control unit,
It is judged to be normal only when the sent diagnostic signal and the feedback diagnostic signal match. Therefore, when the adjacent lines are short-circuited, the signal flowing through one of the two lines is affected by the signal flowing through the other line and changes without fail. In addition, since the disconnection of the line always appears as the disconnection of the feedback signal, it has an excellent effect that a reliable diagnosis can be performed.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining an embodiment of an electronic circuit diagnosing method according to the present invention, and FIG. 2 is a circuit diagram for explaining a conventional electronic circuit diagnosing method. 1 ... Arithmetic control unit, 3 ... Output bus line, 8 ... Selector,
9,10… Data bus lines.

Claims (2)

[Claims] 1. An arithmetic control unit for arithmetically controlling a signal supplied from the outside, and controlling by supplying a control signal according to the arithmetic result from a plurality of output terminals to an object to be controlled via an output bus line. In the electronic circuit, in the diagnostic mode before entering the actual processing of the arithmetic and control unit, while supplying a diagnostic signal to the output bus line from the plurality of output terminals to the adjacent line to the signals of different types to flow, By returning the diagnostic signal in the portion where the signal line exceeds the parallel portion to the arithmetic control unit, it is possible to judge that it is normal only when the diagnostic signal and the feedback diagnostic signal match and shift to actual processing. A characteristic electronic circuit diagnosis method. 2. The electronic device according to claim 1, wherein the pattern of the diagnostic signal is inverted to make two diagnoses, and only when both of the diagnostic results are normal, it is judged to be completely normal. Circuit diagnosis method.