JPH0450676A - Apparatus for diagnosing electronic control substrate - Google Patents

Abstract

PURPOSE:To detect the sign of future trouble with high reliability by a method wherein a predetermined input waveform is preliminarily applied and an output waveform is compared with the comparing standard signal of a comparing standard setting means while the voltage of a power supply is reduced. CONSTITUTION:The voltage of the power supply of a test card 1 to be diag nosed is gradually dropped. That is, a predetermined input waveform is prelimi narily applied and an output waveform is compared with the comparing standared signal of a comparing standard setting means 12 while the voltage of the power supply is reduced and the comparing result 15 is displayed on a display means 21. The test card having high min. normal operation power supply voltage (marginal voltage) has high possibility having any flaw therein and the deterioration judging threshold value of marginal voltage is 8.3V raised by 0.2V from a normal value and this value is set to a rough judging standard.

Description

[Detailed description of the invention] [Industrial application field]

This invention is an electronic control board diagnostic device that automatically tests a printed card (printed wiring board) using an analog IC using a computer, determines whether the card function is good or bad, and automatically displays and records the test results. It is related to.

[Conventional technology]

Figure 4 shows, for example, REC engineer No. 4 FEZ
This is a configuration diagram of the signal switching section of the conventional car 1ζ test device shown in F card test device j published on December 1, 1961 (Ryoden Engineering Co., Ltd.). In the figure, 5 is the test card to be diagnosed (hereinafter referred to as , abbreviated as a test cart) 1, a matrix-shaped signal switching section that switches the connection of the signal generation section 2 and the measurement section 3; 6, a control section that controls the signal generation section 2, the measurement section 3, and the signal switching section 5; , 7 is a recording section for recording test results. Next, the operation of FIG. 4 will be explained below in comparison with the block diagram of FIG. 3. First, the control section 6 controls the signal switching section 5 to connect the signal generation section 2 and the measurement section 3 to the corresponding input/output bin of the card to be tested. Furthermore, the signal generating section 2 is caused to generate necessary signals, and the measuring section 3 automatically measures the test card output signal. If the measurement result is within the criteria, it is judged as good and is left in the recording section 7 as a test record.

[Problem to be solved by the invention]

Conventional diagnostic equipment for electronic control boards is configured as described above, so it makes pass/fail judgments based on reference values, which is effective for determining current failures, but it is difficult to judge the possibility of failures occurring in the future. There were problems such as the difficulty of objectively diagnosing the disease. This invention was made to solve the above problems, and in addition to diagnosing the electronic control board mainly based on input/output characteristics, it also reduces the power supply voltage of the electronic control board to lower the minimum normal operating voltage. The purpose of the present invention is to obtain a diagnostic device for an electronic control board that can also detect symptoms that may cause future failures that cannot be detected by diagnosis based on input/output characteristics alone, by adding a diagnostic function to measure them.

[Means to solve the problem]

A diagnostic device for an electronic side iB board according to the present invention includes a function generating means for inputting an output waveform of a minimum normal operating voltage into a test card, and a comparison standard setting means for setting a comparison reference signal for determining an output signal of the test cart. and a comparison means for comparing the output signal of the test card and the comparison reference signal of the comparison reference setting means to determine normality or deterioration, and displaying the comparison result of the comparison means or the output waveform of the function generation means. and a control means for controlling the power source of the test card and the test conditions of the function generating means. ■Operation] In order to measure the minimum normal operating voltage of the electronic control board in this invention, a predetermined input waveform is applied, and the output waveform is compared with the comparison reference signal of the comparison reference setting means while decreasing the power supply voltage, and the comparison result is is displayed on the display means. This operation determines the deterioration of the test card to be diagnosed. It also detects deterioration test cards that may cause some kind of trouble in the future, which cannot be discovered by diagnosing the electronic control board based on input/output characteristics.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIG.
9 is an output waveform output from the function generating means 8, for example, a pulse waveform (or sine waveform) of about 20 Hz, and 10 is the output waveform 9 used for diagnosing the voltage measuring method Also, the output waveform 9 is a human input signal of the test card 1, and 11 is an output signal. 12 is a comparison standard setting means for setting a comparison reference signal for determination; 13 is a comparison standard signal; and 14 is a comparison means. To set the comparison standard, the output waveform observed on the electronic control board defined as normal is used for evaluation, and the comparison standard is set. For example, the comparison standard is twice the integral value of the difference in output waveforms between the diagnostic reference electronic control boards, and anything exceeding this value is determined to deviate from the diagnostic standard. 15 is the comparison result, 16 is the control means, and if the comparison result 15 is within the standard, test card 1
Appropriately reduce the power supply voltage. 17 is the control B signal, 1
Reference numeral 8 denotes a power supply for the target test cart 1, 19 a power cable connected to the test card 1, and 20 a control signal outputted from the control means 16 to control the parameters of the function generation means 8. 21 is the comparison result 1 output from the comparison means 14
This is a display means for displaying 5. Next, the operation will be explained. First, the power supply voltage of the power supply 18 of the test card 1 is gradually lowered. That is, the minimum normal operating voltage is measured by applying a predetermined input and comparing the output waveform while decreasing the power supply voltage.
The comparison result 15 is displayed on the display means 21. Through this operation, the deterioration of the test card 1 is determined. Next, the concept of pass/fail criteria will be explained. First of all, there is a high possibility that a device with a large minimum normal operating power supply voltage (marginal voltage) has some kind of defect internally, as shown by experiments or actual sites.
This is proven by C data. Although the cause cannot be clearly concluded without disassembling and inspecting the IC, the main causes are presumed to be when a voltage is applied to the IC, or when corrosion occurs inside the IC. From this, it is thought that there is a leakage current due to surge voltage and corrosion, and the power supply voltage for driving the transistor is set to be high. FIG. 2 shows, as a specific example, marginal voltage distributions of normal and degraded digital ICs. For example, while a normal IC operates at a marginal voltage of 8.3V or less, the marginal voltage of a degraded IC is biased toward a level higher than 8.3V.
This proves that it is difficult to operate at low voltages. Regarding the possibility of future failures, it has been experimentally proven that in the case of deterioration caused by surge voltage, if the surge voltage is applied again, the failure will easily occur at an even lower voltage than before. There is. In the case of corrosion, if this progresses further, there is a good possibility that the wiring inside the IC will be disconnected. Therefore, the threshold for determining marginal voltage deterioration is 0 from the normal value based on the experiment shown in Figure 2 and the investigation at the actual factory site.
．． 8.3V, which is an increase of 2V, is used as a tentative criterion for judgment. However, the determination of the threshold value changes depending on the type of target test card, how it is used, etc.

【Effect of the invention】

As described above, according to the present invention, in addition to diagnosing an electronic control board mainly based on input/output characteristics, the input waveform of the minimum normal operating voltage is given to the test card, and the output waveform is measured while decreasing the power supply voltage. The comparison means compares the comparison standard signal of the comparison standard setting means with the comparison means and displays the deterioration judgment result on the display means, so it is possible to prevent future failures that cannot be detected only by diagnosing the electronic control board based on input/output characteristics. This has the effect of being able to detect causative symptoms with high confidence.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an electronic control board diagnostic device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of marginal voltage distribution of normal and degraded digital ICs, and FIG. 3 is a conventional FIG. 4 is a block diagram showing a diagnostic device for an electronic control board, and FIG. 4 is a configuration diagram of the hardware shown in FIG. 3. In the figure, 1 is a test card to be diagnosed, 8 is a function generation means, 10.21 is a display means, 12 is a comparison standard setting means,
14 is a comparison means, 16 is a control means, and 18 is a power source. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In an electronic control board diagnostic device that applies a predetermined input signal to a test card to be diagnosed and compares the output signal of the test card to be diagnosed with a reference value for normal operation to determine pass/fail, the test card to be diagnosed is given a minimum operating value. a function generating means for inputting a voltage output waveform; a comparison standard setting means for setting a comparison reference signal for determining the output signal of the test card to be diagnosed; and a comparison between the output signal of the test card to be diagnosed and the comparison standard setting means. Comparing means for comparing reference signals to determine normality or deterioration; display means for displaying the comparison result of the comparing means or the output waveform of the function generating means; and a power supply and function generating means for the test card to be diagnosed. A diagnostic device for an electronic control board, comprising a control means for controlling test conditions.