JPH07318614A - Function test system - Google Patents

Abstract

PURPOSE:To enhance the quality of a printed board and the inspection efficiency thereof by providing various types of module type function testers and inspection control sections having different inspection functions in order to inspect the functions of a mounting jig and an object to be measured. CONSTITUTION:The functional test system comprises a personal computor 1, a system control 2, a group of measurement control modules 3 corresponding to various function testers, a fixture 4 corresponding to a jig, a bus 5 for function tester, a measuring bus 6, and a measuring instrument 7. The module group 3 comprises various function testers having different inspection functions each comprising a digital multimeter, a power supply control, and a multiplexer module, as a basic specification module, and a universal counter and the like as options. the measurement control module constituting the module group 3 can be combined variously depending on the printed board being inspected such that the function of the printed board for a word processor can be inspected, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an object to be measured such as an electronic device,
For example, the present invention relates to a versatile system composed of various function testers used for a wide range of functional tests of elements, wirings, etc. mounted on a printed circuit board.

[0002]

2. Description of the Related Art In the process of manufacturing electronic equipment in the prior art, various functional tests are carried out in order to guarantee the quality of various measured objects constituting the electronic equipment, for example various printed circuit boards. There are various test systems for performing these functional tests, from simple and inexpensive measuring devices that combine general-purpose testers to expensive dedicated testers built for each printed circuit board, such as digital in-circuit testers. .

Then, using these testers, in order to inspect the function of the circuit composed of elements, wirings, etc. mounted on the printed circuit board, the printed circuit board is placed in a jig, and from the upper side or the lower side thereof. Connect the measurement connection terminal to a predetermined position and supply a predetermined signal to measure the result, or apply a predetermined voltage and observe the fluctuation state of the voltage, or a predetermined frequency. Supply a signal consisting of
It is not limited to a functional test in block units that form elements such as a microcomputer mounted on a printed circuit board, such as how the signal changes, and more reliable by performing a functional test of the entire board. Supplies printed circuit boards, etc.

Therefore, depending on the first item of the function test, extremely accurate data is required, and a high-performance tester, that is, a function tester that simply deviates from the measurement area such as the continuity test is required, and it corresponds to the function test item. It was equipped with a dedicated function tester to perform various functional tests.

In order to operate such a function tester, a dedicated language and a program are analyzed and decoded to create a test pattern for a unique function test, and a unique test item corresponding to an object to be measured is matched. All required specialized skills such as setting measurement items.

[0006]

However, the conventional function tester described above has the following problems.

(1) A large amount of development cost and development time are required for analyzing a circuit on a printed circuit board, creating a test pattern, creating a program, debugging, and the like. In particular, in recent years, the number of printed circuit boards to be inspected has tended to decrease in a large number, so this problem has become a particularly important problem.

(2) Since the test program is created by using a complicated test-dedicated programming language, only a specialized engineer can create it. Therefore, it takes a lot of time to go to the measurement work. The problem is that.

(3) The problem that the function tester, which has a high performance and a high price, has a low investment effect because it is not versatile and can be applied to a wide variety of small quantity printed circuit boards.

(4) Many of them are intended to perform a functional test individually at a component level or a component level. In order to perform a functional test of the entire electronic device, a functional test combining various function testers having different functions is required. The problem is that the configuration is unsuitable.

(5) The problem is that the measurement jig (fixture) is different for each substrate, and the cost required for program creation and debugging is high.

Therefore, there is a problem to be solved by using various function testers having different functions so as to standardize the operations for performing various kinds of different function tests and the measurement procedure.

[0013]

In order to solve the above-mentioned problems, the functional test system according to the present invention comprises:
A jig for mounting an object to be measured, various function testers having different inspection functions for inspecting the function of the object to be measured, and an inspection control unit for operating a function inspection of the function tester, The various function testers are formed in the same module type.

Further, a plurality of slots for inserting the function testers of the various module types into arbitrary positions are provided; the function testers of the various types are connected to the inspection control section by a bus line; The function testers are connected to each other by a bus line; the various function testers are operated by a pseudo panel displayed on the screen; A function test system, which is a printed circuit board, is used as the object to be measured by the various function testers.

[0015]

The function test system according to the present invention configured as described above has the following operation.

(1) Since various function testers having different inspection functions are formed in the same type of module type, they can be made into a compact module group, and a single measuring instrument such as GP-IB can be used. It will be possible to construct a system that can be connected by the bus line and measure in C-language or the like.

(2) By providing a plurality of slots into which function testers of various module types are inserted at arbitrary positions, only the function tester corresponding to the function inspection item of the object to be measured can be appropriately recombined.
For example, it becomes easy to build a system of a dedicated function tester according to customer specifications.

(3) Since various function testers are connected to the inspection control section by the bus line, the operation and inspection procedure can be easily performed even if the function testers corresponding to the inspection items of the measured object are rearranged. For example, it becomes possible to construct a tester that replaces the digital in-circuit tester called high-performance.

(4) By connecting the various function testers to each other by the bus line, the functional inspection of the measured object can be performed by a simple operation even if it is a plurality of items and the overall inspection. For example, it becomes extremely easy to construct a system that can be connected by a bus line such as GP-IB and can be measured in C language.

(5) Since various function testers are operated on the pseudo panel displayed on the screen, the respective function testers can be operated quickly and easily at the same location. For example, you can register the name of the equipped function tester and set the measurement conditions in the same way as you actually operate the operation panel of a single measuring instrument with the pseudo panel.

Further, the measurer can perform the measurement with the same feeling as operating the actual function tester while looking at the measuring instrument pseudo panel displayed on the display screen, and the tester language peculiar to each function tester can be used. There is no need to learn the above and the productivity of inspection is improved.

Furthermore, since a test program consisting of simple test steps can be created on the display screen, the test program can be created easily and in a short time. Since this test program is pre-programmed in detail by the analysis and inspection plan regarding the object to be measured, inspection failure and error do not occur, and therefore the inspection quality is improved.

(6) Since various function testers can be appropriately selected according to the function inspection item of the object to be measured, even if unnecessary function testers are mixed, the function inspection according to the function inspection item is performed. The setting can be easily performed.

(7) Since the objects to be measured by the various function testers are printed circuit boards, even if the printed circuit boards are different in kind and a small amount of various kinds of printed circuit boards, the function inspection item is set according to each of them. Can be done easily.

[0025]

EXAMPLE A function test according to the present invention will be described below.
An example of the system will be described. It should be noted that in the examples, the inspection object, which is the object to be measured, will be described with respect to the printed circuit board.

As shown in FIG. 1, the basic configuration of the function test system of this embodiment is equivalent to a personal computer 1, a system control 2, a measurement control module group 3 corresponding to various function testers, and a jig. Fixture 4 and function tester bus 5
It is composed of a measurement bus 6 and a measuring instrument 7.

The personal computer 1 is a general-purpose personal computer, and its hardware includes CPU, memory,
Display, floppy disk drive, hard disk drive, printer, keyboard, mouse, VM
E-adapter etc. are provided, and as software, general-purpose MS-DOS as an operating system,
It is equipped with software for function testers developed for this general purpose function tester.

This function tester software executes interactive test step definition using an interactive pop panel displayed on the display, without the user having to use a complicated test language as in the past. As a result, anyone can easily develop a test program in a short time.

In addition, the software for the function tester allows the user to operate the virtual instrument pseudo panel displayed on the display with a mouse to perform automatic board inspection and manual operation in the same manner as operating a conventional instrument. It is configured to be able to perform failure diagnosis and the like.

Further, the function tester software is configured to easily perform statistical processing, display, printing, etc. of the inspection result of the printed circuit board which is the measurement object.

The system control 2 selects the measurement control module group 3, carries out the measurement, transfers the measurement result to the personal computer 1 according to various request signals of the user inputted to the personal computer 1 when inspecting the printed circuit board. Control the overall measurement of. The system control 2 is formed in the same shape as a measurement control module described later and is fixedly housed at one end of the measurement control module rack.

The measurement control module group 3 is composed of various function testers having so-called different function tests, each of which is formed in a rectangular shape of the same shape. As a basic specification module, a digital multimeter, a power supply control, and a multiplexer are provided. It has 3 modules and other various options such as universal counter, function generator, waveform test, digital test, digital input / output, keyboard matrix, buzzer LED test, ROM emulation, relay, bar code, GRIB adapter, etc. It has a control module.

The respective measurement control modules corresponding to the above function tester are formed in the same rectangular and thin box shape, and as shown in FIG. 2, they are arranged in parallel in a suitable measurement control module rack 3a. It is adapted to be inserted into a plurality of (for example, 21) slots 3b provided in an arbitrary order. In this way, the compact and small measurement control module group 3 is formed.

Moreover, each measurement control module has a structure in which the position of the slot 3b is not selected and the slot can be freely inserted into and removed from the slot 3b, and the module can be identified by the identification number or the like of each module via the bus. To be determined.

As the measurement control modules constituting the measurement control module group 3, various combinations are possible depending on the printed circuit board to be inspected. For example, the measurement control module group of the function tester such as a printed circuit board for a word processor, a printed circuit board for a multi-function telephone, a printed circuit board for an audio amplifier, etc. can be configured as follows.

(Structure example 1) Function tester for word processor printed circuit board As a basic measurement control module (function tester), (1) Digital multimeter (2) Multiplexer (30 points, connection of four measurement buses) (3) Power control

As an optional module (function tester): (1) Digital test module for sucking up LCD basic data (2) Universal counter for measuring each clock (3) Keyboard matrix for pseudo keyboard (4) ) Buzzer, buzzer LED for checking LED
Test module

(Structural example 2) Function tester for printed circuit board of multi-function telephone The following optional measurement control module is added to the above basic measurement control module. That is, as a basic measurement control module (function tester) (1) Digital multimeter (2) Multiplexer (30 points, connection of four measurement buses) (3) Power supply control-As an optional measurement control module (function tester) , (1) Function generator for telephone line signal generation (2) Relay module for switch setting (3) Keyboard matrix for pseudo keyboard (4) Buzzer LED for checking buzzer and LED
Test module (5) Universal counter for pulse measurement

(Structural Example 3) Function Tester for Printed Circuit Board of Audio Amplifier The following optional measurement control module is added to the above basic measurement control module. That is, as a basic measurement control module (function tester) (1) Digital multimeter (2) Multiplexer (30 points, connection of four measurement buses) (3) Power supply control-As an optional measurement control module (function tester) , (1) Function generator for pseudo tape signal generation (2) Relay module for switch setting (3) Buzzer, LED for checking buzzer LED
Test module

The fixture 4 is a jig for mounting the printed circuit board to be inspected, and a plurality of connection pins for measurement are lowered and raised from the upper side or the lower side to be connected to a specific measurement point.

The VME standard bus 5 is a bus for connecting between the system control 2 and each measurement control module which is a function tester.

The measurement bus 6 is provided between each measurement control module, which is a function tester, and the board to be measured, and
It is a bus that connects the measurement control modules to each other.

The measuring instrument 7 is a conventional measuring instrument, and is connected to the personal computer 1 by the measuring instrument bus 8. Therefore, even in the case of a function test system, a measuring instrument such as a conventional function tester can be used. It has a configuration that can be used as appropriate.

In the function test system configured as described above, for example, the following analog measurement and digital measurement can be performed. 1. Analog measurement 1.1 Input DC voltage measurement 10 μV to 300 V AC voltage measurement 10 μV to 300 V (RMS) Resistance measurement 10 mΩ to 1 MΩ Frequency measurement 0.1 Hz to 100 MHz Period, time interval measurement 100 ns to 40 s Frequency ratio measurement 0.1 HZ to 100 MHz Count 1 to 10,000,000 Arbitrary waveform input Real sampling DC to 5 MHz Equivalent sampling DC to 100 MHz Input maximum number of points 480

1.2 Output Output Waveform SIN Wave, Triangle Wave, Arbitrary Wave, TTL Pulse Frequency SIN Wave 0.5 Hz to 2.0 MHz Triangle Wave 0.5 Hz to 256 KHz Arbitrary Wave 0.5 Hz to 256 KHz TTL 25.6 Hz to 25.6 MHz Voltage range -10V to + 10V (when open) 50Ω Output impedance Output mode Continuous, single, external gate Number of simultaneous output channels 4 channels Maximum number of outputs 480 points at 1MHz or less

2. Digital measurement 2.1 Input Input channel 16 channels / module (maximum 16 modules) Sampling rate 200 ms to 50 ns Pattern length 1 Kbyte (maximum 32 Kbyte)

2.2 Output Output channel 16 channels / module (maximum 16 modules) Output resolution 200 ms to 50 ns Pattern length 1 Kbyte (maximum 32 Kbyte)

3. Others In addition to the above functions, the following can be used. Use of external measuring instrument with measuring instrument adapter 8x8 keyboard matrix 2 channel buzzer, 8 channel LED detection 32 channel relay Pseudo load

The flow of the test program creation from the function tester software in the function test system having the above configuration and function to the execution of the function inspection of the printed circuit board and the failure diagnosis will be described with reference to the flowcharts shown in FIGS. 3 and 4. It demonstrates using.

(1) The board detailed inspection specification is determined based on the inspection specification and the circuit diagram of the printed board to be inspected (steps ST1, ST2, ST3).

(2) Up to 32 test programs are assigned to the printed circuit board by the screen of the interactive pop panel as shown in FIG. 4 which is displayed on the display, and the edit screen is displayed for editing (step ST4). As shown in FIG. 5, the edit screen display shows the results of various functional tests such as voltage shortage, bus timing, and optional measurement control module (function tester) such as pattern output, "PASS" and "FAIL". It is displayed in such a way that even an amateur can understand it with the display such as "

(3) Next, each inspection step of the first test program is defined and the measurement control module is selected (step ST5). The inspection step can be defined by a simple command step (fail stop, step retry) using a high-performance edit command (delete, copy, paste, insert).

The inspection step can be debugged step by step. Also, as a step failure dictionary,
It is possible to input a comment of maximum 256 characters.

(4) The measuring instrument pseudo panel is displayed on the display, thereby setting each measurement condition (step ST6).

(5) Press the EDIT button on the measuring instrument pseudo panel to set the automatic judgment standard (step ST
7).

(6) The above steps ST5 to ST7 are repeated for all the inspection steps in this test program (step ST8).

(7) When the editing of the test program is completed, steps ST4 to ST8 are repeated for the next test program (step ST9).

(8) When all the test programs in the test project have been edited, the test project and the test program are stored in a recording medium such as a floppy disk (step ST10).

The test program is created in a maximum of 256 steps for each functional block or physical block of the printed circuit board, and a maximum of 32 test programs are combined into one test project, stored in a recording medium and made into a library. It

(9) The stored test program is read to perform a functional inspection (GO / NG inspection) of the printed circuit board (step ST11). The functional inspection can be freely performed from the automatic test to the manual measurement for the printed circuit board diagnosis with the same feeling as operating a real measuring instrument by the measuring instrument pseudo panel. Also, the test steps can be scrolled during the inspection.

(10) When the result of the inspection is "GO", an inspection report is created and printed, and then the process proceeds to the next step (step ST12).

(11) When the result of the inspection is "NG", NG (defective) information is printed (step ST1).
3). The NG information can output the NG rate for each test program, the worst 10-step information, and the like by abundant statistical processing functions.

(12) With respect to the test program or the inspection step which has become NG, the defective portion is judged by the detailed measurement in the defective dictionary function and the manual measuring mode (step S
T14), repair the defective portion (step ST1)
5). In this case, the sampling function allows manual adjustment while displaying the measurement data.

Thus, the operations required for various functional tests can be performed while viewing the screen through the test procedure that is standardized in this way. Among the basic measurement control modules that are function testers, a digital multimeter, a universal counter in an option module, a digital test module, and a digital input / output module will be described below with reference to the drawings.

1. Digital Multimeter 1.1 Overview A 5-digit floating balanced digital multimeter is composed of a measurement control module and a measuring instrument pseudo panel.

The printed circuit board to be inspected is used as a stand-alone measuring instrument by connecting it to the terminals on the front panel of the module, or a matrix board (MPX board) as shown in FIG. 6 displayed on the screen is used. Multiple points of voltage and resistance can be automatically measured.

On the MPX screen, the measurement bus and extraction pin can be connected using a mouse for each test step.

1.2 Features (1) Measurement function DC voltage AC voltage resistance measurement (2) Normal noise can be removed by using the integral A / D converter. (3) Common mode voltage can be removed by the floating balanced input. (4) The measurement accuracy can be automatically adjusted by auto zero and automatic adjustment. (5) The measurement can be activated by an external trigger. (6) Upon receiving the trigger, up to 100 measurements (sampling) can be designated.

1.3 Specifications and Functions (1) The digital multimeter has dimensions of VXI bus B size (160 mm × 234 mm) and occupies 2 slots (width 40 mm) of the measurement control module rack.
The power supply voltage is + 5V, + 12V, and -12V.

(2) Measurement function and range DC voltage measurement: 0V to ± 300V (input from front panel) 0V to ± 40V (MPX, input through rear connector) AC voltage measurement: 0V to ± 300Vrms (input from front panel) 0V to ± 40Vpp (input via MPX, rear connector) Frequency 20Hz to 10KHz AC coupling Resistance measurement: 0Ω to 1MΩ (3) Input method: Floating balanced type Impedance: 10MΩ (4) A / D converter method: Integral AD Conversion resolution: 3 bytes Integration time: 100 μs, 2.5 ms, 20 ms, 320 ms 16.7 ms, 267 ms (when using a 60 Hz power supply) (5) Trigger function: Trigger source Immediate, bus, external modes: Trigger delay 1 ms to 10 s (6) Number of sampling times: 100 times maximum (7 Automatic correction: auto-zero and offset correction

1.4 Usage of Digital Multimeter 1.4.1. Input Characteristics and Connection The input terminal of the digital multimeter is a floating balanced differential type insulated from the main body as shown in FIG. 7, and the impedance between the terminal HT and the terminal COM is equal.
The only difference between the HT terminal and the LT terminal is the polarity.

A measuring instrument pseudo panel of the digital multimeter is shown in FIG. When setting “Input is MPX” on the instrument pseudo panel, set the HT input to A of the measurement bus.
Connect the LT input to the B bus and the COM terminal to the ground. As a result, the measured voltage and the measured resistance are input to the digital multimeter through the A bus and the B bus by the MPX board.

On the measuring instrument pseudo panel, "input is FR
When set to “ONT”, the COM terminal is connected to the ground, and the HT terminal and the LT terminal are connected to the LT terminal and the HT terminal of the module, respectively.

1.4.2. DC voltage measurement Connect both the LT and HT terminals of the input to the board under test. When measuring the voltage at other points with respect to the ground, the LT terminal is connected to the ground. The resolution is selected according to the range and aperture time (or integration time).
As the integration time, one cycle of AC power supply or 16 cycles can be selected. Table 1 shows the resolution of voltage measurement when the range and the integration time are specified.

[0075]

[Table 1]

1.4.3 Measurement of AC voltage The method of measuring AC voltage is the same as the measurement of DC voltage. A
The measurement of the C voltage is performed by AC coupling. Therefore, no DC offset is applied. Further, since the RMS converter is used, the non-sinusoidal voltage can be accurately measured.

1.4.4 Measurement of Resistance The resistance is calculated by turning on the internal current source, generating a voltage across the unknown resistor, and dividing the generated voltage by the applied current to calculate the resistance. Table 2 shows the resolution of resistance measurement.

[0078]

[Table 2]

The resistance is measured by the two-wire method, and the resistance of the measurement lead is ignored. Further, when inputting from the MPX board, when the automatic correction setting is turned on, the ON resistance of the MPX board is measured, and it is corrected by subtracting it from the measured resistance value.

1.4.5 Range Setting Range setting includes manual range and auto range. When set to Auto Range, the digital multimeter will sample the input signal and select the correct range when triggered.

The measurement range is set in consideration of the following according to the level of the input signal. (1) Select the lowest possible range for best resolution. (2) In the automatic test, measure in the manual range. However, when setting a step, the range can be queried by autoranging. (3) In order to obtain high resolution, the integration time is lengthened (the test time is lengthened).

1.4.6. Setting the integration time The integration time is the time that the digital multimeter samples the input signal. Specifying the integration time determines the normal mode rejection rate (NMR). Measurements are often normal mode noise, especially 50Hz or 60Hz
Because it is performed in the presence of noise generated from the
Noise is averaged and removed by an integration process during A / D conversion.

In setting the integration time, it is necessary to consider the following points. (1) Normal mode removal of noise of 50 Hz or 60 Hz requires an integration time of 20 ms (50 Hz) or 1
Only achieved at 6.7 ms (60 Hz). (2) When the integration time is lengthened, the NMR becomes higher but the reading speed becomes slower. (3) The measurement resolution decreases as the integration time becomes shorter.

1.4.7. Trigger and Sample Settings The digital multimeter operates in idle and wait trigger states. In the idle state, each parameter is set to make it measurable and wait for the trigger. When the trigger is received, measurement is performed.

It is possible to set the measurement to be performed once for each trigger, and in this case, each time the measurement is completed, the idle state is restored.

The sample has a function of measuring a plurality of designated times (up to 100 times) for each trigger, or a function of receiving a plurality of triggers. In the former case, the digital multimeter returns to the idle state after the measurement of the specified number of samples is completed.

In the latter case, that is, in the state of waiting for a trigger, as shown in the flowchart of FIG. 9, the number of triggers and the number of samples are designated and the state of waiting for a trigger is entered (ST16, ST17).

When the trigger signal is received from the designated signal source, the trigger state is set (ST18, ST
19).

When the triggered state is reached, the measurement is delayed by the designated delay value (ST20, ST21).

The measurement is performed a designated number of times for each trigger, and when the measurement of the designated number of triggers is completed, the device returns to the idle state (ST20, S).
T21, ST22).

Here, the triggered state, that is, the trigger source can set any of the following three modes. (1) IMM mode (immediate mode) In this mode, an internal trigger signal is always generated when the digital multimeter is in a trigger waiting state.

(2) EXT Mode In this mode, the external trigger supplied to the "External Trigger" connector on the front surface of the digital multimeter serves as a supply source, and the digital multimeter is triggered by the rising edge of the TTL signal.

(3) Bus mode The trigger source in this mode is the signal from the cross trigger line of the measurement bus. When the trigger code corresponding to the digital multimeter appears on this cross trigger line, the digital multimeter is triggered.

By setting the trigger count, the number of triggers received by the digital multimeter from the trigger wait state to the idle state (maximum 1
00 times) can be specified.

Further, by setting the trigger delay,
Time from trigger to measurement (0000ms-9999m
s) can be specified. Further, by setting the sample count, it is possible to specify the number of times of measurement (up to 100 times) to be executed each time the trigger signal is received.

A plurality of continuous measurement intervals, that is, the sample period is 64 ms at the maximum. The sample period must be longer than the integration time.

1.4.8. Autozero The digital multimeter's autozero function is to remove the offset voltage inherent in the digital multimeter from the DC voltage and resistance measurements.

When autozero is set to on, the digital multimeter measures the input voltage, then either the input signal is internally disconnected or the current source is cut off and then the offset voltage is measured, the difference between the two measurements being taken. Is the measured voltage value of the digital multimeter. This measurement value is also used for resistance measurement.

1.4.9. Offset correction The offset correction of the digital multimeter is a function of canceling the offset voltage generated inside and outside the digital multimeter during resistance measurement as follows. (1) Turn on the current source and measure the voltage induced across the resistor. (2) Next, the current source is turned off and the offset voltage is measured. (3) Next, the difference between the measured voltages in (1) and (2) is taken, and the difference is divided by the applied current.

The offset correction can be used in any range, but in the highest range, the value of the induced voltage is much larger than the offset voltage, so that the influence of the offset voltage on the measurement accuracy is negligibly small.

2. Universal Counter 2.1 Overview The universal counter is a register type module that occupies one slot of the measurement control module rack as hardware.

Further, the universal counter is displayed on the screen of the display as a measuring instrument pseudo panel as shown in FIG. It is possible to input an input signal from the front of the measurement control module and use it as a single measuring instrument, or to perform multi-channel automatic measurement using an MPX board.

The universal counter having such a structure has two channels, channel A and channel B. Specifications and functions are as follows for both channels. (1) Frequency measurement Measuring range: 0.2 Hz to 100 MHz (DC coupling) 100 Hz to 100 MHz (AC coupling) Resolution: 1 / gate time (2) Average period measurement Measuring range: 100 ns to 40 s (DC coupling) 100 ns to 10 ms ( AC coupling) Resolution: 10 ns (3) Pulse width measurement Measuring range: 200 ns-40 s (DC coupling) 200 ns-10 ms (AC coupling) Resolution: 100 ns (4) Time interval Measuring range: 200 ns-40 s (DC coupling) 200 ns-10 ms (AC coupling) Resolution: 100ns (5) Additive counting Counting range: 1 to 1,000,000 Minimum pulse width: 10ns (6) Frequency ratio (7) Time base Frequency: 10MHz Stability: 2ppm year stable Degree: 2 ppm / year Temperature characteristics: 5 ppm (0 ° C to 50 ° C or higher) (8) Input signal conditioning (each channel cannot be set separately) Input sensitivity: 25 mV (0 db) 250 mV (20 db) Coupling: DC or AC impedance: 1 MΩ (parallel 50 pF or less) 50 Ω (parallel 50 pF or less) Filter: 100 KHz low-pass filter Attenuation: 0db or 20db (9) Trigger level: -2.54V to + 2.54V (0db) -25.6V to + 25.6V (20db) Effective edge: rising or falling

2.2. Preliminary knowledge before using the universal counter 2.2.1 Default state The universal counter is set with default values of input and measurement parameters as shown in Table 3 when the power is turned on and when it is reset.

[0105]

[Table 3]

2.2.2. Input Signal Conditioning Before measuring a signal, it is necessary to correctly select the input signal conditioning regarding amplitude, frequency, periodicity and repeatability. For both A and B channels, event level, event slope, input attenuation, input coupling, and impedance can be selected. Also, a low pass filter can be used.

The settings of attenuation, coupling, impedance, and low pass filter are the same for both channels A and B. For example, if the input impedance of channel A is set to 50Ω, the input impedance of channel B is also set to 50Ω. However, the event level and event slope can be set separately.

Input signal conditioning of each parameter will be described below. 2.2.2.1 Event level The event level represents the amplitude of the input signal to be measured. When the power is turned on or reset, the event levels of both A and B channels are set to the default value of 0V, and the measurement is started when the input signal passes 0V.

2.2.2.2 Event Slope Event slope represents the rising or falling slope of the input signal to be measured. When making time interval measurements, specify the event slope to specify the rising or falling edge that starts or ends the measurement. Further, the event slope is used for designating a positive or negative pulse width when measuring the pulse width.

2.2.2.3. Input coupling Channels A and B of the universal counter are AC
The input coupling scheme, either coupled or DC coupled, is selected. Two examples of AC coupling required for input coupling
1 and FIG.

The example of FIG. 11 is a case of measuring a high frequency signal which is included in an extremely low frequency signal. When the amplitude of the low-frequency signal is large as described above, the measurement target signal exceeds the maximum value of the event level setting, so that the universal counter cannot be triggered and a trigger error occurs. Therefore, if the input is AC-coupled and low frequency components are removed, the signal under measurement can be triggered at the event level, and as a result, an accurate count can be obtained.

In the example of FIG. 12, the measurement target is 200 mV.
This is the case where the signal has a DC component of 18 mV. If the signal falls within the range of the event level by being attenuated by a factor of 10, the signal under measurement is attenuated by 200 mV and does not reach the sensitivity of the universal counter. Therefore, if the input is AC coupled and the direct current component is removed,
The mV signal can be measured at an event level of 0V.

DC coupling specifies the input signal at DC level. At the input to DC coupling, the event level that starts the measurement can be set to a point on the waveform.

2.2.2.4 Input Impedance For both channels, the input impedance can be set to either 1 MΩ or 50 Ω.

2.2.2.5 Input Low Pass Filter The cutoff frequency is 100 KH in both channels.
A low pass filter of z can be selected. This has the effect of reducing the influence of normal noise during measurement, and is particularly important for measuring the period.

2.2.3. Selection of Time Base for Frequency Measurement When a universal counter measures frequency and frequency ratio, it is necessary to select a time base as a time for sampling the input signal and determining the frequency. This time base directly determines the resolution and range. Table 4 shows the relationship between the time base and the range.

[0117]

[Table 4] The resolution is the minimum amount of change that can identify the difference. The higher the resolution, the larger the time base and the slower the measurement.

2.2.4. Number of cycles for measuring average cycle and range In a universal counter, the number of cycles is the number of cycles for sampling the input signal and measuring the cycles. This determines the resolution and range that can be obtained with the period measurement. Table 5 shows the relationship between the number of cycles and the range.

[0119]

[Table 5]

2.3 Using the Universal Counter To use the universal counter, after familiarizing yourself with the nature of the signal you want to measure, selecting the input signal conditioning and measurement commands correctly, and setting the input parameters as described above. , Perform the measurement as follows:

2.3.1 Frequency measurement The frequency measurement range is DC to 100 MHz. FIG. 13 shows an example of measuring the frequency of the audio receiver. In this case, in channel A, a 10 MHz sine wave IF
The signal is measured and channel B measures the detector output at 2100 Hz. The input amplitude is ± 10V.

In this case, each parameter is set as follows. Event level: Since the input signals are all 0V and symmetrical, the event level is set to 0V. Event slope: Changing the event slope does not affect the frequency measurement.

Attenuation: Select 20 db. Binding: Select AC coupling. Low pass filter: Not used. Input impedance: Use 1 MΩ. Time base: 1024 ms for CHA, CH
In B, 16 ms is used.

2.3.2 Measurement of average frequency The measurement range of average frequency is from 200 ns to 40 s. As an example, the input signal of channel A is 1MHz
The parameter setting for measuring the TTL signal of is performed as follows. Event level: With the TTL signal, the event level is set to + 1.2V.

Event slope: Changing the event slope does not affect the frequency measurement. Attenuation: Select 0db. Binding: Select DC coupling. Low pass filter: Not used. Input impedance: Use 1 MΩ. The number of cycles: 8192 is used.

2.3.3. Pulse width measurement Positive pulses are pulses from the rising edge to the falling edge, and negative pulses are pulses from the falling edge to the rising edge. Measuring range is 1
00 ns to 40 s.

Each parameter is set as follows when the pulse width W of the horizontal synchronizing pulse in the composite video signal as shown in FIG. 14 is measured. Event level: Set the event level to + 2.0V Event slope: Specify the falling edge. Attenuation: Select 0db. Binding: Select DC coupling. Low pass filter: Not used. Input impedance: Use 50Ω. The number of cycles: 1024 is used.

3.3.4. Measurement of time interval The start and stop of the time can be selected from the rising edge and the falling edge of the pulse, respectively. The range is 200 ns to 40 s. To measure the time interval T between the falling edges of the horizontal sync pulse in the composite video signal as shown in FIG. 14, the same signal is input to both channels A and B.

In this case, each parameter is set as follows. Event level: The event level is set to + 2.0V Event slope: CHA and CHB both specify the falling edge. Attenuation: Select 0db. Binding: Select DC coupling. Low pass filter: Not used. Input impedance: Use 50Ω. The number of cycles: 1024 is used.

3.3.5. Measurement of frequency ratio The frequency ratio is measured on channel A and channel B, and the ratio of the measurement results is taken. Maximum frequency ratio is 1E9D
Therefore, the minimum frequency ratio is 1E-9. FIG. 15 shows an example of measuring the frequency ratio in a circuit that generates a frequency different from the original frequency.

The measurement time of the frequency ratio is determined by the frequency of the input signal and the number of periods to be measured. That is, when the input signal has a low frequency, the measurement takes a long time. Set each parameter as follows. Event level: Set the event level to + 1.2V Event slope: Setting does not affect the measurement.

Attenuation: Select 0db. Binding: Select DC coupling. Low pass filter: Not used. Input impedance: Use 1 MΩ.

3.3.6. Additive Counting Additive counting can be performed on channel A or channel B. The maximum reading is 999999. Reading the count does not stop the addition counting. Once started, counting continues until a command is written.

4. Digital test module 4.1 Overview The digital test module efficiently tests the digital functions of the printed circuit board by supplying bit data and patterns to the printed circuit board and inputting the timing chart, pattern data, etc. output from the printed circuit board. It is designed to do well. Up to 2
A pattern of 1024 states 16 channels can be generated at a clock rate of 0 MHz to sample 16 channels of data.

4.2 Configuration FIG. 16 shows the configuration of the digital test module. 4.2.1 Pattern input The specifications for pattern input are as follows. Number of channels: 16 channels Input level: -40V to + 40V Clock: Internal clock 5Hz to 20MHz External clock Maximum 20MHz Pattern length: 1K (standard), 4K, 16K, 32
K (option) Trigger: CH1 to CH4 level or edge: CH5 to CH16 level Cross trigger impedance: 100KΩ

Input timing data of 16 channels from the connector CN1 is sampled at a maximum of 20 MHz, and the sampled data is stored in the FIFO memory. The host computer reads the contents of the FIFO memory through the VME interface and the cross trigger interface, displays the waveform of the timing data, and compares it with the standard waveform to perform a digital test.

Also, using the control panel displayed on the display, the sampling clock rate of the pattern, the length of the sampling data, the trigger (whether pattern trigger or edge trigger), the test mode, etc. are set as follows. .

(1) Sampling rate The internal sampling rate is 50 ns to 200 ms.
It can be set in one step. The external clock is input from the probe pin.

(2) The length of sampling data is 10
0 bit to 16K bits can be set in 5 steps.

(3) Trigger Types of triggers include pattern triggers and edge triggers. Pattern trigger is 1,0 for all channels
It is an AND condition consisting of the levels of, and it is possible to invalidate any channel. The edge trigger is an O that consists of a rising edge and a falling edge.
R condition. Further, there is an AND condition between the pattern trigger and the edge trigger.

Trigger position setting is 0, 1/4, 1 /
It is a function that can be set in four stages of 2, 3/4, and sets the length of sampling data before the trigger and the length of sampling data after the trigger. For example, if the length of the sampling data is set to 400 and the position of the trigger is set to 1/4, 100 data before the trigger and 3 data after the trigger are set.
00 pieces of data are written in the memory.

The cross trigger is a function of starting data sampling by a trigger code from the cross trigger bus 6 (trigger signal of hexadecimal 55 digits from another measurement control module).

(4) Allocation of threshold voltage The threshold voltage of each channel is the same. Available threshold voltage is TTL, -40V-40
V can be set in 20 steps.

4.2.2. Pattern output The pattern output specifications are as follows. Number of channels: 16 channels Output level: TTL (other levels are possible depending on the probe box) Clock: Internal clock 5Hz to 20MHz External clock Maximum 20MHz Pattern length: Memory 1K (standard), 4K, 16
K, 32K (option) Trigger output: Outputs the trigger to the cross trigger bus at the specified point. Pattern method: Single mode Outputs the pattern of the set length once. Continuous mode The pattern of the set length is repeatedly output.

Edit the pattern in the control panel,
The pattern clock rate, pattern data length, cross trigger, output mode, etc. are set as follows.

(1) The internal clock rate is 50 ns
1 ms can be set in 14 steps. The external clock is input from the probe pin.

(2) The length of sampling data is 10
0 bit to 16K bits can be set in 5 steps.

(3) Pattern output mode In the single mode, the pattern of the set length is output once, and in the continuous mode, the pattern of the set length is repeatedly output.

(4) The output level can be selected by the probe box. (5) Cross trigger output The cross trigger code is output at the set point in the pattern. This cross trigger code can activate or deactivate other measurement control modules.

5. Digital Input / Output Module 5.1 Overview The digital input / output module is a register type module, and includes an isolated digital input / output module and a TT.
L digital input / output module.

5.2 Isolated Digital Input / Output Module The isolated digital input / output module has an input and an output of 30 points each isolated by photo isolation, and supplies an isolated internal power source to the input / output circuit. Also, it is configured to allow a flexible connection with an external device.

5.2.1 Input Circuit As shown in FIG. 17, a chatteringless circuit is provided at all inputs of the input circuit of the isolated digital input / output module in order to remove noise from an external device. The terminal is equipped with a photo coupler.

The specifications of the input circuit are as follows. Number of inputs: 30 points Input current: Internal supply 8mA or more (at low level 12V) External supply 8mA or more (at low level 12V) Filter input: All inputs are equipped with a filter to remove chatter of 2.3ms or less There is. Input connection: 34 pin for flat cable Isolation: Provided for all inputs.

5.2.2. Output Circuit The output circuit of the isolated digital input / output module is shown in FIG.
As shown in, a photo coupler is mainly provided as an external device interface. The specifications of the output circuit are as follows. Number of outputs: 30 points Output voltage: Internal power supply 12V External power supply 25V (maximum) Output current: Minimum 5mA, normal 12mA,
Maximum 30mA (at low level) Output connector: 34 pin for flat cable Isolation: Provided for all outputs.

5.2.3 Output power setting The output power of the module can be set by the relay R using the host software.
The power supply of the photocoupler can be set to the input side by operating 1, and the power supply of the photocoupler can be set to the output side by operating the relay R2.

5.3 TTL Digital Input / Output Module The TTL digital input / output module is a 64-point TTL.
It has level input / output and can perform input, output, or high impedance setting in 8-bit units. FIG. 19 shows an input / output circuit per point.

Although a typical measurement control module has been described above, other measurement control modules are also configured according to their respective functions, but detailed description thereof will be omitted.

The external dimensions of each measurement control module are V
The size of the IX bus B is compactly accommodated in the slot (20 mm) of the measurement control module rack and can be freely inserted and removed in any order, and various combinations can be configured depending on the board to be measured.

Further, each measurement control module is displayed on the screen of the personal computer 1 as a measuring instrument pseudo panel, and by operating in the same sense as operating a real measuring instrument, the functional inspection of the printed circuit board can be performed efficiently. To be able to do.

[0160]

As described above, the general-purpose function tester according to the present invention has the following effects.

(1) By installing a function tester in a small space without providing a dedicated function tester for each printed circuit board to be measured as in the past, it is possible to easily perform a functional test on all measured objects, for example, a printed circuit board. Since it can be performed in a short time, it has an extremely excellent effect that a high investment effect can be obtained.

(2) Since the function tester can be connected by a bus line and combined inspection can be performed,
For example, after the analog inspection at the component level or the component level, the digital inspection at the printed circuit board level can be performed, and the functional inspection can be performed with high versatility, and the inspection can be completed completely. It has an extremely excellent effect of contributing to the improvement of the quality.

(3) Since the function inspection items can be set by the screen display, for example, the test program necessary for the function inspection can be easily created and debugged, so that even a non-specialized test engineer can easily and easily perform the test. The operation procedure of the functional inspection can be created in time, the inspection efficiency can be improved, and the productivity can be increased, which is an extremely excellent effect.

(4) By operating the measuring instrument pseudo panel displayed on the display, the inspection can be performed with the same feeling as operating an actual measuring instrument. Therefore, there is an extremely excellent effect that the quality of the examination is improved.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the overall configuration of an embodiment of a function test system according to the present invention.

FIG. 2 is an explanatory diagram showing an appearance of the same embodiment.

FIG. 3 is a flowchart showing the operation of the embodiment.

FIG. 4 is a flowchart showing the operation of the embodiment.

FIG. 5 is an explanatory diagram showing an example of an editing screen display according to the embodiment.

FIG. 6 is an explanatory diagram showing a screen display example for the multiplexer in the embodiment.

FIG. 7 is an explanatory diagram showing an input of the digital multimeter module in the embodiment.

FIG. 8 is an explanatory diagram showing a measuring instrument pseudo panel of the digital multimeter.

FIG. 9 is a flowchart showing an operation of the digital multimeter.

FIG. 10 is an explanatory diagram showing a measuring instrument pseudo panel of the universal counter according to the embodiment.

FIG. 11 is an explanatory diagram showing an example of frequency measurement by the universal counter.

FIG. 12 is an explanatory diagram showing an example of frequency measurement by the universal counter.

FIG. 13 is an explanatory diagram showing an example of frequency measurement by the universal counter.

FIG. 14 is an explanatory diagram showing an example of pulse width measurement by the universal counter.

FIG. 15 is an explanatory diagram showing an example of measuring a frequency ratio by the universal counter.

FIG. 16 is a block diagram showing a configuration of a digital test module of the same example.

FIG. 17 is an explanatory diagram showing a configuration of an input circuit of the isolated digital input / output module.

FIG. 18 is an explanatory diagram showing a configuration of an output circuit of the isolated digital input / output module.

FIG. 19 is an explanatory diagram showing a configuration of an output circuit of the same TTL digital input / output module.

[Explanation of symbols]

 1 PC 2 System control 3 Measurement control module group 4 Fixture 5 VME bus 6 Measurement bus 7 Measuring instrument 8 Measuring instrument bus

Claims (7)

[Claims] 1. A jig for mounting an object to be measured, various function testers having different inspection functions for inspecting the function of the object to be measured, and an inspection control unit for operating the function inspection of the function tester. A function test system characterized in that each of the various function testers is formed in the same module type. 2. The function test system according to claim 1, further comprising a plurality of slots into which the function testers of various module types are inserted at arbitrary positions. 3. The function test system according to claim 1, wherein the various function testers are connected to the inspection control unit by a bus line. 4. A bus line connecting the various function testers to each other.
The function test system according to 2 or 3. 5. The function test system according to claim 1, wherein the operation of the various function testers is performed by a pseudo panel displayed on the screen. 6. The function test according to claim 1, 2, 3, 4 or 5, wherein each of the various function testers can be appropriately selected according to a function inspection item of the measurement object. system. 7. The function test system according to claim 1, wherein the measurement object measured by the various function testers is a printed circuit board.