JPH0242368A - Wiring inspection system - Google Patents

Abstract

PURPOSE:To simplify a relay circuit being complicated together with increment of pattern numbers by providing a resistor part having plural resistors of different values instead of providing a relay circuit part connecting an inspecting circuit and ohmmeter. CONSTITUTION:An inspecting system is constituted of a resistor part 3 wherein resistors R1, R2, R3, R4, R5 having different resistance values connected with each patterns of an object to be tested 1, are connected in series, and an ohmmeter 2. The resistors R1, R3, R5, are respectively connected with patterns A, B, C in parallel, the R2 and R4 connects between A-B and between C-D respectively. Also, measuring terminals (d), (e) of the ohmmeter 2 are respectively connected with a terminal point (a) of the pattern A and terminal point (c) of the pattern C. And, by measuring the resistance value by the ohmmeter 2, the resistance value corresponding to a disconnection and short-circuit state of each pattern is obtained. Consequently, the measuring once and comparing normal resistance value with the resistance value being measured, it is possible to detect the disconnection and the short-circuit of each patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wiring inspection method, and particularly to a wiring inspection method for inspecting short circuits and disconnections in circuit patterns of printed wiring boards and the like.

[Conventional technology]

The conventional wiring inspection method uses a resistance meter to measure the circuit pattern within the test object and the resistance value between the two patterns;
It was configured to include a relay circuit section for connecting the resistance meter to two points of the circuit pattern to be tested.

Next, a conventional wiring inspection method will be explained in detail with reference to the drawings.

FIG. 3 is a block diagram showing an example of a conventional wiring inspection method. The wiring inspection system shown in FIG. 2. Here, patterns A, B, and C in the test object 1 are printed wiring board 1--as shown in FIG.
The first-class circuit patterns AI + 81 and CI are simplified and expressed as straight lines.

First, in order to check for disconnection in pattern A, the relay circuit section 4 closes between a and d and between a' and e, and the resistance meter 2
The resistance value at both ends a-a' of the pattern A is measured. At this time, if there is no break in the pattern A, the measured resistance value will be a minute value, and conversely, if there is a break, the resistance value will be large.

Similarly, the disconnection of pattern B can be inspected by connecting between b and d and b' and e, and the disconnection of pattern C can be inspected by connecting between c and d and a'e.

Next, the relay circuit section 4 closes between a and d and between b' and e, so that the resistance meter 2 measures the resistance between two points included in pattern A and pattern B. Here patterns A and B
If there is no disconnection and there is a short circuit between the pattern A and the putter 78, the measured resistance value will be minute; on the other hand, if there is no short circuit, the resistance value will be large.

Similarly, short circuits between patterns B and C can be tested by connecting between b and d and between c' and -e, and short circuits between patterns A and C can be tested by connecting between a and d, c and -e. can. On the other hand, if there is a disconnection in pattern A, in order to check for short circuits between pattern A and other patterns,
end point a.

It becomes necessary to check each a' independently for short circuits with other patterns.

Therefore, if the number of normal patterns among all patterns is Nl, and the number of patterns with wire breakage is N2, the wire breakage test will be performed Nl + N2 times, and the short circuit test will be performed Nl + In the example of the above three patterns, each pattern will have no wire breaks. If all patterns are broken, 3+6C2=18 tests are required.

[Problem to be solved by the invention]

In the conventional wiring inspection method described above, each circuit pattern in the DUT is tested independently, so the relay circuit for switching the connection between the ohmmeter and the patterns becomes complex as the number of patterns increases. However, as the number of measurements increases, the number of measurements increases and the inspection time becomes longer.

[Means to solve the problem]

The wiring inspection method of the present invention includes a resistor section in which a plurality of resistors having different resistance values are connected in series and a circuit pattern to be inspected is connected to each connection point, and a resistor section connected to both ends of the resistor section. It consists of a resistance meter.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention.

The wiring inspection method shown in FIG. 1 uses resistors R1, R2, and R
5, R4, R5 are connected in series, resistor section 3 and resistance meter 2
It consists of:

Here, the test object 1 is a simplified representation of circuit patterns A, B, and C of a printed wiring board or the like as shown in FIG.

In FIG. 1, resistors R1, R3+R5 are connected in parallel to patterns A, B, and C, respectively, and R2, R.

connects patterns A and B and patterns B and 0, respectively. Furthermore, measurement terminals d and e of the resistance meter 2 are connected to the end point a of the pattern A and the end point C' of the pattern C, respectively. Here, by measuring the resistance value with the resistance meter 2, the following values can be obtained depending on the state of disconnection and short circuit of each pattern.

No disconnection or short circuit...R=R2+R4 (R: measured resistance value) Pattern A disconnection...R=R2+R4+R.

Pattern B disconnection...R=R2+R4+R3 Pattern C
Disconnection...R=R2+R4+R.

Short circuit between A-8... Short circuit between R=R2+R4-R2B-C... Short circuit between R=R2+R4-R2O-A...
R=R2+R4-R2-R.

Therefore, in one measurement, by comparing the normal resistance value and the measured resistance value, it is possible to detect disconnections and short circuits in each pattern.

Here, the resistance values of resistors R1 to R5 must be different values in order to identify the defective location, but for example, R2-2R1,R,=4R1,R
If 4=8R1 and R5=16R, the following failure diagnosis can be made based on the measured value R.

R=10R1...No disconnection or short circuit R'' 11 R1...Pattern A disconnection R=14R1・
...Pattern B disconnection R=26R1...Pattern C disconnection R=8R□ ...Short circuit between A and B R''2 Rs ...Short circuit between B and C R=O...C
Short circuit between -A Next, when the number of circuit patterns on the DUT 1 is very large, it becomes difficult to use the required number of different resistance values.

FIG. 2 is a block diagram showing a second embodiment of the invention.

By using a resistor section having a plurality of resistor blocks composed of resistors R1 to R6 of different resistance values, the pattern to be inspected is divided into blocks, and by providing a relay circuit section for selecting the inspection block. , the inspection within each block can be performed once.

〔Effect of the invention〕

The wiring inspection method of the present invention provides a resistor section having a plurality of resistors of different values instead of providing a relay circuit section for connecting each wiring pattern in the object under test and a resistance meter. This makes it possible to simplify the relay circuit section, which becomes more complex as the number of patterns increases, and also to significantly reduce the number of tests, thereby making it possible to shorten inspection time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a second embodiment of the invention, FIG. 3 is a block diagram showing an example of the conventional technology, and FIG. 4 is a block diagram showing a third embodiment of the present invention. It is a detailed view of the wiring pattern of the test object shown in the figure. 1... Test object, 2... Resistance meter, 3... Resistor section, 4... Relay circuit section, A, B, C... Wiring pattern, R1* R2, R3R
4. R5+ R6...Resistor.

Claims (1)

[Claims] The resistor section includes a resistor section in which a plurality of resistors having different resistance values are connected in series and a circuit pattern to be tested is connected to each connection point, and a resistance meter connected to both ends of the resistor section. The acceptability of the circuit pattern to be inspected is determined by comparing a plurality of estimated composite resistance values calculated based on a combination of the resistance value of the device and the circuit state of the circuit pattern to be inspected with the actual resistance value of the resistance meter. A wiring inspection method characterized by: