CN2263349Y - Total circuit testing intelligence meter - Google Patents
Total circuit testing intelligence meter Download PDFInfo
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- CN2263349Y CN2263349Y CN 95240365 CN95240365U CN2263349Y CN 2263349 Y CN2263349 Y CN 2263349Y CN 95240365 CN95240365 CN 95240365 CN 95240365 U CN95240365 U CN 95240365U CN 2263349 Y CN2263349 Y CN 2263349Y
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Abstract
The utility model provides a miniaturization 'palmtop type ' sized total circuit testing intelligence meter, which is an integral function meter which integrates seven kinds of general necessary maintenance meters, such as a multimeter, a logic pen, a frequency meter, a signal generator, a digital IC off-line and on-line testing instrument, a line fault automatic diagnostic instrument, etc. The utility model adopts a single chip computer and an A/D chip as a core to respectively form a digital plate circuit and an analog two plate circuit. An alternating power supply of the manual control of the two plate circuits can be realized according to test content, a power consumption automatic control and a dormancy wakeup circuits are arranged in the single chip computer, the design of a time-sharing multiplexel circuit is adopted by the utility model, the operation of an interactive mode between a person and a machine by five emulated keys can be completed, and the component number and the power consumption of the utility model can be reduced. The volume, the power consumption and the cost of the utility model is same with the volume, the power consumption and the cost of the existing digital multimeter, and the similar products do not appear at China and other countries.
Description
Essential measuring instrument when the application relates to electronics and electric utility service equipment, particularly a kind of miniature " palm formula " whole circuit test smart instrumentation.
Electronics and electric utility when service equipment, by relate generally to many years ago analogue circuit develop into relate generally to simulate, numeral and touch, number hybrid circuit (abbreviation whole circuit), the most frequently used have four kinds of instrument.Multimeter, logic pen, frequency meter and signal generator, also have three kinds of instrument in addition, though maintenance during digital circuit of great use, but because of its price height, volume is big, power consumption is high and can't popularize use, and they are: digital integrated circuit chip off-line and on-line testing instrument and line fault automatic diagnostic instrument, difficulty is bigger when lacking these three kinds of instrument, maintenance digital circuit.More than seven kinds of instrument total prices need tens thousand of units, must pile a desk during use, total several Ampere currents of power consumption 220V power supply.
Above seven kinds of maintenance indispensable instrument commonly used can be combined into-body, and with its microminiaturization, make it suitable with " palm formula " digital multimeter of using at present aspect price, volume and power consumption, be exactly the application's goal of the invention.
In order to realize the application's purpose, need to solve two technological difficulties, the one, the unit weight problem of memory, because what test at present that digital circuit chip all adopts is tradition " exhaustive learning method ", as test a certain model chip, assisting into the pin number is N, then computing machine needs when design the exhaustive study of the good sheet of this model 2N group test patterns, each group coding is the multibyte of N bit, surveys, and the test result that obtains is stored in the instrument as permanent code, after instrument is made, if test same model chip then by comparing one by one with the permanent code that is stored in the instrument, can be differentiated the quality of chip under test.Will store the code book of hundreds of sheet chip as an instrument, its database is inevitable huge, and because the test duration is long, power consumption is inevitable big, and instrument is difficult to use dry cell to make power supply, volume also must increase.Therefore, do not see so far that both at home and abroad the precedent that microminiaturization is accomplished in above seven kinds of instrument merging is arranged.
The utility model has solved above-mentioned technological difficulties, at home and abroad first the major function of seven kinds of measuring instruments commonly used is comprehensively become-body, and realized microminiaturization, technical scheme is as follows: the electronic circuit of this instrument be divided into simulate and the numeral two plates, simulating plate and be with A/D conversion swallow lcd drive chip is core, the configuration operational amplifier, liquid crystal radix point driver and hummer chip for driving are formed, by placing function measurement range selection waver and the socket on the casing, the hole is finished combined-voltage and is measured, and hands over directly to flood current measurement, resistance capacitance is measured, crystal two, triode is measured, signal source simulates signal generation and analogue circuit signal tracing row barrier; The numeral plate is that the single-chip microcomputer with computer program stored and database is a core, the configuration address decoding scheme, frequency and logic state test circuit, data-latching circuit, IC chip test drives the digital signal source circuit of holding concurrently, expansion input port and digital circuit LCD driver are formed, by placing emulation button and the test jack hole on the casing, finish to simulate and imitate the word signal frequency and measure, the digital signal logic state is measured, and digital circuit tracks and arranges barrier, digital integrated circuit chip off-line and on-line testing, line fault is test and the generation of signal source numeral signal automatically; The connection characteristics of each circuit are in the numeral plate: the single-chip data line connects the input end of data latches, output line of single-chip microcomputer is made power consumption control company data latches and is always exported the permission end, the single-chip microcomputer address wire connect address decoding circuitry assist into, the output of address decoding circuitry provides that multi-plate chip latchs trigger pip in the data latches, the output of data latches is assisted into linking to each other with the digital integrated circuit chip driver, each output of digital integrated circuit chip driver links to each other with digital integrated circuit chip test jack pin, each pin of test jack test chip links to each other with the input of expansion input port, the expansion input port is assisted out with the single-chip microcomputer incoming line and is linked to each other, interrupt line of single-chip microcomputer is made dormancy awakening and is linked to each other with the common junction of several emulation buttons, the other end of each emulation button is to link to each other with the single-chip microcomputer output line respectively, a sheet choosing of address decoding connects the digital circuit lcd drive chip, and the single-chip microcomputer output line connects this chip data input and position input pin; Measure that the frequency of jack base input and logic testing signal send frequency and logic test circuit shaping and frequency division, the low-and high-frequency signal that decomposites connects single-chip microcomputer low-and high-frequency input port respectively, logic state is connected by the logic incoming line expands the input port, through the expansion mouthful the conversion after by single-chip microcomputer-incoming line collection, the power consumption line connects frequency and the logic state test circuit is done the high-impedance state differentiation, and the corresponding pin with test jack of single-chip microcomputer programmable signal edge output pin links to each other.Two liquid crystal display drive chip identical characters sections of analog-and digital-plate drive output pin and connect, the positive pin of simulation plate A/D chip power is supplied with after the voltage stabilizing current limliting by positive source, the negative pressure feeding that the negative pin of simulation plate A/D chip power is produced through the positive-negative power conversion chip by positive source, numeral plate lcd drive chip positive supply pin is supplied with after step-down by positive source, this chip negative supply pin ground connection also is connected to the electrolysis filtering circuit in the positive supply line of positive and negative power supply of A/D chip power and digital lcd chip power; The digital block plate is powered by placing the two wave band multipole switches single solution for diverse problems on the casing to change with the power supply that simulates plate, a power supply, then another piece outage, another cutter of this switch will switch the back electrode pin of two lcd drive chips of two plates synchronously, have only a chip back electrode to link to each other with the LCDs back electrode, the display screen back electrode links to each other with the stabilivolt negative pole, stabilivolt plus earth; Utilize the working time analysis-by-synthesis of program with each working signal in the numeral plate circuit, find out the signal multiplexing that does not coincide on time domain, they are: single-chip data output line (D
0～D
7) be the corresponding D of all output triggers of data-latching circuit
0～D
7Input pin is multiplexed, output line (AD
4) to connect button, shift register, LCD driver three tunnel multiplexing, output line (AD
1～AD
3) connect button, LCD driver two tunnel is multiplexing, output line (AD
5) connect shift register, LCD driver two tunnel is multiplexing, programmed signal source output pin (AD
0) gang socket, button, LCD driver three tunnel is multiplexing.
Below in conjunction with drawings and Examples the course of work and the operating feature of this instrument are done further narration.
Fig. 1 is a block diagram of the present utility model;
Fig. 2 simulates the plate wiring diagram for the utility model;
Fig. 3 is the utility model numeral plate wiring diagram;
Fig. 4, Fig. 5 are the utility model casing external form figure.
Referring to Fig. 1-5, to unify in order to realize seven kinds of instrument functions, and reach the purpose of miniaturization, this instrument circuit is drawn Be divided into and simulate and digital two macroplates, the address decoding circuitry in the digital plate is a slice decoder chip, frequency and patrolling Collecting the state verification circuit is a slice Schmidt reshaper and a slice frequency divider, and data-latching circuit is that five ternary outputs trigger Device, the IC chip test data signal source circuit of holding concurrently is three Darlington drivers, and the expansion input port is two displacements Register, the amplifier that simulates in the plate is three amplifier chips. Simulate the seal that the plate main parts size is arranged in the instrument front On the brush wiring board (upper plate), the main in addition arrangements of components (lower plate) on the printed substrate of instrument reverse side of digital plate. Simulated according to tested object by the operator after instrument powers up and measure or digital measurement is stirred power selection switch to a plate The piece power supply, another plate then cuts off the power supply. Simulating plate consumption in operation electric current has reached the No.5 cell service index and has not made further merit Automatically control is carried out further in consumption control, digital plate power consumption, and it is to be come by single-chip microcomputer power consumption control line and dormancy awakening line Implement control, the output that the power consumption control line connects whole ternary output triggers in the data-latching circuit allows pin, and dormancy is called out Awake line connects the common port of all emulation buttons, and two lcd drive chip identical characters of two plates section drives pin and connects branch The time LCDs section input pin drive sharing. Numeral each circuit of plate and main connection features are: single-chip microcomputer eight Data lines connects the corresponding D input of all ternary output triggers of data-latching circuit. Single-chip microcomputer power consumption control output line (AD6) connect the output of these triggers and allow end. Single-chip microcomputer three bit address line (AD7～AD
9) and write line (AD10) respectively decoder chip address pin and input allow pin in the decoding circuit of ground connection location. The decoder output chip Select signal (CS1～CS
5) connect respectively every ternary output trigger clock pin. Ternary all output pins of trigger (T1～T
40) access Islington driver input pin. Driver output pin (P1～P
10，P
15～P
24) Patch the input of seat leg and expansion input port. The expansion input port uses shift register to implement also-the string change numerous input pins After changing, its output (D8～D
11，D
15) connection single-chip microcomputer input line. Emulation button common junction line connects single Sheet machine dormancy awakening line. Each another end points of emulation button connects respectively single-chip microcomputer output line (AD0～AD
4). A sheet choosing of address decoder (CSO) lcd drive chip, single-chip microcomputer output line (AD0～AD
5) connect This chip data input and position input pin. Frequency or the logic testing signal of measuring the socket input switch (K switch through jack In two cuttves) send to frequency and logic state test circuit through the smit circuit shaping, behind the digital frequency divider frequency division, decomposite High-frequency signal is from D14Line connects single-chip microcomputer high-frequency count input port, and low frequency signal is from D13Line connects single-chip microcomputer low frequency counting input port, and logic state connects from logic input line (L) expands the input port input, after the conversion of expansion input port by single-chip microcomputer input line D8Gather. Power consumption control line (AD6) connect frequency and the logic state test circuit is made high impedance status Judge and use. Single-chip microcomputer programmed signal source output pin (AD0) gang socket P11Pin.
Two plate lcd drive chip identical characters section driver output pin also connect, and have swarmed into the digital integrated circuit chip two condition The forbidden zone that output pin can not and connect. It must have following connection features to guarantee, otherwise liquid crystal can not normally show very To burning chip. Its connection features is: simulate plate monolithic A/D conversion hold concurrently lcd drive chip positive supply pin must be by Positive source is supplied with (this voltage called after V+) through resistance and voltage-stabiliser tube voltage stabilizing and current limliting, and the negative supply of this chip Pin must be that positive source is supplied with through the negative pressure (called after V-) of positive-negative power conversion chip generation. Numeral plate liquid Brilliant driving chip positive supply pin is to supply with (called after Vc) by positive source after two silicon diode step-downs, and this chip is negative Supply pin connects power cathode (ground connection). Because two plate power supplies are to carry out two-way switching by the cutter in the K switch, All the time only may there be a lcd drive chip to obtain power supply. Another cutter switches this two liquid crystal with bi-directional synchronization in the K switch Drive the back electrode pin of chip, only have a chip back electrode pin to link to each other with LCDs back electrode pin. LCDs Back electrode connects a voltage-stabiliser tube negative pole, this voltage-stabiliser tube plus earth (power cathode). V+, V-and Vc must be connected to Electrochemical capacitor filtering. Numeral plate components and parts connecting line is a lot, for saving line and using less the input and output extended chip, originally Utility model adopts the unique connection of following time-sharing multiplex, and the program of single-chip microcomputer will effectively be controlled time-sharing multiplex. Be specially: 1. single-chip data line (D0～D
7) be that five ternary output triggers are multiplexing, use 3 address (A D of single-chip microcomputer7～AD
9) a write line AD10Be defeated by decoder, obtain CS after the decoding1～CS
5Connect respectively The clock pin of 5 ternary output triggers is implemented time division multiplexing.
2. output line AD4Connect button, shift register, LCD driver three tunnel is multiplexing.
3. output line (AD1～AD
3) connecting button, LCD driver two tunnel is multiplexing.
4. output line (AD
5) connecting shift register, LCD driver two tunnel is multiplexing.
5. programmed signal source line (AD
0) gang socket, button, LCD driver three tunnel is multiplexing.
6. power consumption control line (AD
6) output that connects all ternary output triggers of data-latching circuit allows pin, the Si Mite reshaper, the Darlington driver is multiplexed.
7. dormancy awakening line (D
12) connecting all emulation, to connect the key public point multiplexed.
8. integrated circuit test socket P
1It is multiplexing that the 1st pin was made when the signal source function the strong driving pulse of 32 of per second outputs two tunnel again when pin was promptly done chip testing.
9. 4 test pencil jacks of instrument have three multiplexing, they be V and, CoM GND, MA and F.
10. LCDs time division multiplex.
A LCDs timesharing is two plate services, and two lcd drive chips of two plates, 27 same section separately drive pin and display screen same section input pin, implement the three and directly connect.
Five emulation button multiplexings reach 21 of this instrument actual needs by strong effect.
Most important basic test is that one group of test patterns acts on each pin of test jack in the numeral plate.Its function Characteristics is: the power consumption control line has been put high level when resetting, and data latches output is forbidden.Each group test patterns is formed (each byte is 8 bits) by five bytes.Single-chip microcomputer uses 5 addresses to divide 5 times from D by byte
0～D
7Data line is sent into data-latching circuit and is latched.Latch finish after, single-chip microcomputer just makes power consumption control line output low level, latch output allows to open, 40 binary codes are exported simultaneously, it sends to the input of Darlington driver, the Darlington driver is according to these 40 binary codings, to produce a kind of (high level, low level, the high resistant) of three kinds of states of test jack each pin of 20 pin, the Darlington driver can be sent maximum 100mA at high level, the low level maximum can absorb 100mA, so can compatibility serve as chip power pin and the strong drive signal of on-line testing.The pin (input pin) of measurand excitation is sent to high level or low level excitation when needing, and needs the pin (output pin) of test measurand response will send to high resistant.The response current potential will be decided by this reaction under the instrument excitation of measurand.Single-chip microcomputer reads in these responsive states by the expansion input port, in case read in finish this moment single-chip microcomputer to put the power consumption control line be high level, the whole output pins of data-latching circuit are high resistant, the high resistant of these output pins will make the Darlington driver enter static little power consumption state, and its output also all presents high impedance.Single-chip microcomputer deals with this group excitation and response this moment again.Every group of test patterns has only tens microseconds between action period.The difference of several groups of basic test code characters cooperates will form test patterns on multiple populations, finish different tasks, and tens groups even hundreds of cohort test patterns will be finished a certain chip or many line faults are diagnosed.Single-chip microcomputer uses a power consumption control line, adopts grouping earlier to latch and finishes, and collective exports together again, can avoid the transition mistake combination in the distribution process.Data latching and Darlington drive operation time are only kept tens microseconds, and making promptly so has the also safety of entail dangers to gauge internal chip and chip under test not of error code.
The utility model adopts middle and small scale digital integrated circuit chip off-line test, three functional hardware circuit of on-line testing of middle and small scale digital integrated circuit chip and line fault automatic diagnosis are compatible entirely, simplify hardware circuit, with software different disposal in addition, it is to have single-chip microcomputer to be furnished with data-latching circuit, address decoding circuitry, the digital integrated circuit chip test driver, four parts in expansion input port are formed by connecting.Data-latching circuit is characterized as and latchs one group of test patterns (it is made up of a plurality of bytes) that the single-chip microcomputer timesharing is sent.Its preferred plan is made up of d type flip flop or D-latch that output allows control can implement ternary output for using multi-disc.The d type flip flop of use two condition output and D-latch and microcomputer EingangsAusgangsSchnittstelle also can be finished this function.Address decoding circuitry is used for data-latching circuit multi-disc trigger or latch should be by that sheet trigger or latches to single-chip data line time division multiplex time zone divided data.Being characterized as of driver: each output pin has three kinds of above current drive capability of state high level 100mA, and low level has the above current capacity of the 100mA of absorption, and it is small to drive this pin circuit power consumption during high impedance in the chip.Three kinds of states of each output pin have three binary codings of its corresponding two input pin to obtain, having this condition driver just can be at this circuit working, when preferred plan increases these two input pins and is high resistant, its corresponding internal drive circuits presents no power consumption, when power consumption control, latch put earlier that to make driver be high resistant coding, latch that output is allowed is invalid, make latch be output as high resistant, carry out dual fail-safe power consumption of driver is controlled.
The expansion input port is for each pin state of test chip socket is offered single-chip microcomputer.It can be to adopt shift register to implement parallel serial conversion, and serial input single-chip microcomputer input port also can be adopted and parallelly directly sending to the single-chip microcomputer input port, also can utilize triple gate to be connected with address bus with the single-chip data bus with address decoder and implements.Also can utilize the microcomputer EingangsAusgangsSchnittstelle to implement.Also can several schemes be used in combination.
The utility model adopts the frequency analog signal test; the digital signal frequency test; three functional hardware circuit of digital signal logic five state verifications are complete compatible; simplify hardware; use the in addition technology of different disposal of software; this technical scheme is characterized as: test signal is divided into direct current earlier and exchanges two passages; direct current channel has the high resistance current limliting and shields; schmidt shaping circuit, shaping are arranged; after this signal processing; read its state by the single-chip microcomputer input port, adopt output line of single-chip microcomputer, whether no signal presents the high impedance use to make the judgement test point.
The analog or digital AC signal; through communication channel; there is partiting dc capacitor to remove the direct current composition earlier; apply again one fixedly DC voltage arrive near the threshold level of schmidt shaping circuit; in in current limliting and frequency compensation electricity and limiter protection circuit to the schmidt shaping circuit input end; the digital signal of exporting after shaping is divided two-way, and one the tunnel directly imports another frequency measurement input port of single-chip microcomputer.Single-chip microcomputer uses these three mouths to utilize software algorithm to test automatically three functions.
This instrument changes the one all power consumption designs of all components and parts of start of traditional circuit instrument, designs a kind of operator's complicated operation degree power consumption control type feature that do not increase.Be specially: 1, as mentioned above, entire machine design is two plate structures, when the operator selects the plate function, uses two forward motion key, and Overall Power Consumption is reduced on a large scale.
2, simulation plate little power consumption is no longer made power consumption and is further controlled.
3, digital plate is further made automatic power consumption control again.Single-chip microcomputer has two power consumption states, work power consumption and dormancy power consumption.Single-chip microcomputer is an auto sleep after finishing a certain function, and the operator carries out other function again, then passes through D behind the button
12Line dormancy awakening single-chip microcomputer enters duty.Single-chip microcomputer only passes through AD in test patterns between action period
6The power consumption control line is put low level, just wakes data-latching circuit and IC chip test drive circuit works up, in case do not need its work, AD
6Line is put high level makes it enter the static little power consumption of dormancy.
4, this instrument power supply has in-line power and two kinds of modes of external source of stable pressure power supply.Because on-line testing digital integrated circuit chip and line fault, instrument is by the on-line testing annex, each pin drive signal of chip testing socket extended to weld in the circuit board on each pin of chip under test and on the test line, so it not only will drive chip under test and test line, but also to drive other chip and components and parts by line on the wiring board, therefore this moment, instrument adopted use equipment under test power drives equipment under test selftest object and the required power supply of instrument.Instrument adopts external source of stable pressure mode and equipment under test to be powered by equipment under test simultaneously.All the other function consumption electric currents of instrument are little, and chargeable battery is directly powered in the employing machine, and instrument is furnished with the chargeable battery charging socket.
Below in conjunction with embodiment each main circuit is described below:
One, simulation plate circuit
Simulation plate circuit is mainly with U
18(examples of implementation are 7106,7126 or 7136) and many grades of multitool function range switches (X) are the core built-up circuit, and it has been extensive use of this universal circuit both at home and abroad with DT890C+ digital versatile watch circuit, is not described.U in three amplifiers
16, U
21Select TL062 for use, U
22Select LM358 radix point driver U for use
20Select CD4070 for use, buzzer driver U
15Select CD4011 for use.The AC/DC of this plate conversion and buzzer circuit be in lower plate, i.e. U
15And U
16Two chip built-up circuit parts.Having only power suppling part to divide to its change partly is connected with liquid crystal drive.
Two, digital plate liquid crystal display drive circuit and key circuit
Because liquid crystal and button must be in the instrument fronts, so their circuit is placed on upper plate.Lcd drive chip adopts 4 seven sections lcd drive chip U
17(examples of implementation are 7211AM).To lcd drive chip AD
0～AD
3Send 4 character display codes, AD
4, AD
5Indicated number is at that, CS
0Be the sheet choosing.Five emulation buttons, public collateral contact connects single-chip microcomputer D
12Dormancy is waken line up, AD
0～AD
4Connect five another contacts of key respectively.Single-chip microcomputer is after finishing a certain task, when next step operation one is decided to be operator's button operation, with AD
0～AD
4Be changed to low level, auto sleep.Have only the operator to carry out button operation, by arbitrary key, D
12Line will be coupled as low level by key contacts, D
12The line low level will be waken single-chip microcomputer up, and single-chip microcomputer passes through AD at this moment
0～AD
4And D
12Cooperation can learn further why key is pressed, and carries out corresponding assigned operation, and operation is finished, and puts AD again
0～AD
4The low level secondary dormancy.AD
0～AD
4In not dormancy of single-chip microcomputer, duration of work will be other components and parts work service.
The numeral plate drives lines with the lcd drive chip section of simulating plate 27, adopts a simple liquid crystal drive screen of driving in parallel (25mm word Senior Three position half LCDs is selected in enforcement for use).These two plates only have a power supply.These two chip for driving back of the body electroplax lines do not adopt parallel connection, and a cutter K-4 switches and then switching with plate in the second gear four blade waver and adopt.The LCDs back electrode connects a stabilivolt negative pole, stabilivolt plus earth.Two special connection methods of plate lcd drive chip will guarantee the liquid crystal operate as normal.
Three, jack commutation circuit
This instrument is only used 4 test pencil jacks, and measured frequency and logic state need be introduced signal from test pencil in digital plate function.Two cuttves switch and then switching synchronously with plate in use K-1 and the K-2 second gear four blade waver.
Four, one chip microcomputer circuit
This instrument function is mainly by the VLSI (very large scale integrated circuit) U of one chip microcomputer
1Type selecting has following requirement:
1. working current requires can accept below the average 25mA at battery, and quiescent current is that working current is with below 1/3rd.These two electric currents are the smaller the better naturally.And have a dormancy awakening, and change by extraneous level, it can be waken up from dormant state.
2. there is the above read-only memory of 8K byte inside, and inner single-chip microcomputer has 256 byte random memories except that using register.Do not have this condition and use that to extend out the memory design good, but will increase the volume of instrument.
Low-and high-frequency was measured a mouthful use when 3. inside had two 16 digit counters as measured frequency, had one 16 bit timing device to use as the programmed signal source frequency divider.
4. has the eight bit data line, 3 address wires, a write line, 13 input and output dual use lines.
5. has quartz crystal oscillator circuit (greater than 6 megahertzes), reset circuit.
Meet the single-chip microcomputer of these features, embodiment has 68HC705C8,87C52 and 89C52 etc.
Five, middle and small scale digital circuit chip and line fault diagnostic circuit
This instrument is utilized 20 pin of the positive 24 pin IC chip test sockets of instrument to make this partial function and is used.It is one group of test patterns test that middle and small scale digital circuit chip and line fault are diagnosed basic test unit.To every group of binary-coded difference of test patterns, every group of test patterns independent test or several groups of necessary test patterns joint tests will be combined into various different test feature and performance, thus the multiple-task of finishing.Hardware circuit only need to implement one group of test patterns test of assurance to finish, and all the other are the work of software.
To 20 chip testing pin of the instrument integrated chip testing socket of numeral, instrument must be implemented following three kinds of states to its each pin: 1. high level drives and requires drive current to reach more than the 100mA, output voltage subtracts 0.3V greater than supply voltage, 2. low level drives, require and ABSORPTION CURRENT to reach more than the 100mA, output voltage is less than 0.3V, 3. high impedance.Could adapt to its each pin like this and again chip be done the supply pin driving, can do off-line or on-line testing again and drive the chip under test input pin, can do off-line or on-line testing again and connect tested chip output pin.
One group of test code character effect hardware circuit process is as follows:
One group of test code character has 40 binary codes (five bytes), and single-chip microcomputer uses five different addresses to pass through AD these five bytes
7～AD
10Send address decoding circuitry (U3, embodiment are 74HC138), under the location input at this point, it exports CS
1～CS
5Five byte data codings are delivered to its corresponding ternary output trigger latch trigger (U
4～U
8Embodiment is 74HC374) after all latch data finished, single-chip microcomputer made AD
5The power consumption control line becomes low level by high level, AD
6The output that line connects five triggers allows on the pin, and output this moment allows open, 40 output pin T of five triggers
1～T
40Embody the encoding state of one group of test patterns simultaneously.T
1～T
40Be connected to three Darlington driver (U
9～U
11Embodiment is 94C80) input end, input end is received coding, will on 20 pin of chip testing socket, embody the test coding, therefore chip under test input pin and the supply pin high or low level that will obtain being scheduled to drives, the corresponding driving of chip under test output pin pin is a high resistant, so this pin state is decided by chip under test internal logic relation, is executed outside instrument under the input stimulus by chip under test, exports its corresponding level state.The empty pin of chip under test also uses high resistant.Chip under test is when off-line test, and supply pin Vcc is as high level, and GND drives as low level.Because each output pin of this instrument Darlington driver has the 100mA driving force, so they are no problems as supply pin.The chip under test supply pin is for the power supply of test line plate, so the driving pin of corresponding power pin is a high impedance during on-line testing.Single-chip microcomputer need be understood this 20 pin at test patterns each pin state between action period, and it is by its expansion input port D
8, D
9, D
10, D
11, D
15Learn five input ports.Its 20 pin has 16 pin to be connected on by U
12And U
13On 16 input pins of 17 bit shift register that two eight bit shift register (examples of implementation are CD4021) cascade forms.Single-chip microcomputer output line AD
5Connect these two shift register modes and select pin, its high level is a parallel input mode, and low level is a displacement mode.Output line AD
4Connect this two shift register clock input pins.The 17 bit shift register serials output of cascade meets single-chip microcomputer D
8The input port.Single-chip microcomputer passes through AD
4, AD
5Effect, can be with 16 pin (P of test jack
1～P
8, P
17～P
24) state transfers serial to from D by parallel
8The input port seals in single-chip microcomputer, and single-chip microcomputer reads in this 16 pin states.Other has 4 pin state single-chip microcomputers directly from D
9, D
10, D
11, D
15Read the input port, they and 4 pin (P of test jack
9, P
10, P
15, P
16) link to each other.
In case single-chip microcomputer has read 20 pin states, this group test patterns effect is gone over, and single-chip microcomputer makes AD
6The power consumption control line becomes high level by low level, and this moment, five triggers were output as high resistant immediately, oneself became static power consumption state (not bringing onto load), and every power consumption is 20 μ A, and three drivers enter little power consumption state at this moment.Single-chip microcomputer does not change AD after sending one group of test patterns
6Power consumption control line low level state is sent second group of (all or part of) test patterns again, and these two groups of test patterns are cooperated, and simulates the rising edge or the negative edge of required pin.In like manner, organize test patterns also can synthesis more.Many assembly unification dawn finish AD
6Put high level by low level, allow this circuit enter dormancy.One group of basic test sign indicating number is the microsecond level between action period.
With instrument annex " on-line testing folder ", will drive pin and extend on the circuit-under-test plate chip under test pin during on-line testing from test jack.The line fault diagnosis will drive pin and extend on tested many circuits from test jack with instrument annex " line test hook ".Article two, circuit is short circuit or does not connect mutually, and actual is two kinds of different logic behaviors, it can be analyzed out by specific driving method and algorithm.
Six, frequency and logic state test circuit
Measured signal imports from F and two jacks of GND, switches by jack to enter frequency and logic state test circuit, and it has three passages from single-chip microcomputer direct current mouth (D
8), exchange low frequency counting mouthful (D
13), exchange high-frequency count mouth (D
14) detect.Direct current and very low frequency (VLF) (less than one week of per second) status signal is through R
9The resistance protection current limliting is through secondary Si Mite phase inverter shaping U
2-embodiment is 74HC14), through the multiplexing D of 17 bit shift register
8Its state is read in the input port.Want and AD during read states
4, AD
5Line cooperates, and allows shift register make 17 bit shifts and just can obtain direct current mouth state.AD
6Line is through R
11Apply high-low level to tested pilot, if the measured point is high level or low level, AD
6State variation is through R
11High resistant (being embodied as 100K) will can not influence the measured point state.If the measured point no signal is a high-impedance state, single-chip microcomputer is from D
8Direct current mouth detected state will be with AD
6State variation and changing.Use this method can detect high resistant.
Test point such as AC signal are through C
18The stopping direct current coupling capacitance is through R
7, R
8, W
4Divider resistance promotes quantitative DC level to U
12The threshold level place regulates W
4Can regulate and promote DC voltage.Again through R
6, C
16Built-up circuit current limliting and high-frequency compensation are through D
3, D
4Amplitude limit, U
2The smit circuit shaping.Can guarantee input signal in the 50mV-18V voltage range, analog and digital signal all can be shaped to the same frequency square-wave signal, and one the tunnel directly gives single-chip microcomputer D
13The low frequency mouth, the one tunnel through U
14(U behind 128 frequency divisions
14Examples of implementation are 74HC393), arrive single-chip microcomputer D again
14The high frequency mouth.Use this two mouths, cooperate two the sixteen bit counters and the automatic regulating gate time of single-chip microcomputer of single-chip microcomputer inside, can finish 1HZ～30MHZ automatic frequency measurement on a large scale.Because so single-chip microcomputer is to use quartz oscillator as benchmark frequency test precision height when frequency measurement.
Seven, signal generator and signal tracing row barrier
This instrument utilizes above the digital integrated circuit chip 24 pin sockets 4 pin to do signal source output, and other has the output of P1 pin double as signal source.Chip Microcomputer A
0Be the programmable signal extraction slit, its guiding digital integrated circuit socket P11 pin can drive four TTL loads.The operator can select frequency division value, range of choice N=1-65535 by the emulation button.AD
0The output frequency Counting Formula is 1.5 million ÷ N (using 6,000,000 crystal oscillators to make the single-chip microcomputer clock) or 3,000,000 ÷ N (using 12,000,000 crystal oscillators).Capacity measurement socket CX left side has the 400HZ sinusoidal signal to draw.Digital integrated circuit socket P1 pin has the strong driving digital signal (drive current reaches 100mA) of 32 pulses of per second.P14 has liquid crystal back electrode digital square-wave (50HZ), and U is arranged during the work of simulation plate
18Provide, digital plate has U when working
17Provide.P
12And P
13There is one second-inferior monopulse driving digital signal, by single-chip microcomputer output line AD
6Supply with variable signal.The signal source square-wave signal not only has the first-harmonic composition to utilize, and its higher hamonic wave also can be the mimic channel utilization.And square-wave signal itself is to be fit to digital circuit use.
With signal generator and this instrument self measuring voltage, electric current, frequency and logic five state verifications are used, and can implement track row barrier of mimic channel and Digital Circuit Signal.
Eight, power-supply circuit
Internal power supply directly links to each other with circuit ground with the external power supply ground wire.Just youngly open or close through power switch (PSW) control power supply.Select in the second gear four blade waver on K-3 one cutter to plate again.When this cutter was placed the D shelves, power supply was supplied with digital plate VD with power supply, is converted into Vc through two silicon second tube sheets step-down (D17, D18) again and uses for the digital lcd driving circuit.VD will directly supply with the Darlington driver and use, and VD is converted into Vcc after-individual silicon second tube sheet step-down, for other chip use.Simulate the plate non-transformer and connect this moment.When K-3 placement A shelves, the digiboard block power supply cuts off, and positive source is converted into V+ after R74 current-limiting resistance stabilivolt DWl voltage stabilizing, and positive source is converted into V-through U19 (examples of implementation TCLT660).Use V+ and V-to the power supply of this instrument simulation plate.Charging socket adopts and the charging of power switch (PSW) interlocking form, only places the OFF position at the PSW switch and could charge, and will guarantee so can not enter appliance circuit because of the maloperation charging voltage.This electricity is working voltage 5-6.3V slightly, uses No. 5 rechargeable batteries of 5 joints in the machine, and circuit can connect at battery polar and shield inverse time.
This instrument to manipulate method as follows:
One, analog board block operations
Use many grades of multitool function range switches (X) to carry out function and measurement range selection operation.
Two, digiboard block operations
The digiboard block operations adopts the man-machine conversation mode; The instrument display reminding, the operator uses button operation.Instrument implements all to operate the operation that needs 21 buttons (0-9 numerical key and 11 function keys) in fact but only use 21 keys of 5 key emulation through ingenious design, called after emulation key), this is that the utility model is exclusive, it makes miniature instrument dwindle volume, moulding is simply attractive in appearance, and the sign of five buttons and layout are as shown in Figure 4.The numeral plate is all operated branch four classes:
The first kind: digital input operation, instrument need be with input two or three tens digits (routine chip under test model, frequency division value etc.), need two liquid crystal of input or ten to be shown as " 0 ", need three of inputs, liquid crystal is at hundred, and ten, individual position shows " 0 ".Manipulating button is defined in button bottom sign and can realizes.Method :+1 ,+2 ,+5 three buttons are responsible for liquid crystal and are being shown that unit numbers adds key value, and it abandons with ten.Individual position is shown on the position.
Be responsible for the circulation of binary digit or three a bit digital left side and move, by once moving one (two or three instrument oneself know).
Key is responsible for end number and is assisted into operation, determines the instrument value of the current displayed value of liquid crystal for user's announcement at last.
Second class: function selecting operation
Button top left sign is used in instrument liquid crystal display " 1-5L " this moment.The I key is selected for the line fault self-diagnostic function.The F key is that frequency and logic state test function are selected.The S key is a digital integrated circuit chip on-line testing function selecting.The LV key is the digital integrated circuit chip off-line test.
The 3rd class: test chip series selection operation
The instrument liquid crystal display: " 1750 ", use the right sign in button top this moment.The P key selects special chip series (factory and individual self design chip) 74 keys to select 74 series, and 40 keys are selected CD4000 series, and 45 keys are selected CD4500 series and 75 series.
The 4th class: method of testing is selected
When liquid crystal display " UPU2 ", use square mark on the button, P represents to select comprehensive characteristics sign indicating number method of testing, and 2 select the 2N methods of testing.Finish when carrying out the good chip study of learning test, after the replacing chip is chip under test, will carry out learning test by LN key instrument.
Because the utility model volume, power consumption, the similar multimeter of price, the pocket of can packing into is carried, and operates simple and easyly, and function is strong.Be undoubtedly a major transformation to general purpose instrument.Use it can directly improve maintenance circuit quality and speed, reduce constituent parts and personal investment instrument and the expense of safeguarding instrument.The utility model is applicable to that the laboratory of each universities and colleges uses, each research institution uses and each factory, enterprise, individual's maintenance electronics and electrical equipment use at the development test circuit, and the shop also can be used when sale electronic devices and components and digital integrated circuit chip test.
Claims (4)
1, a kind ofly be applied to electronics and electric field service equipment essential " palm formula " whole circuit test intelligence table, with existing multimeter, logic pen, frequency meter, signal generator, the structure of high line of digital integrated circuit chip and on-line testing instrument and seven kinds of Common Instrument of line fault automatic diagnostic instrument also is incorporated into one with the major function of above seven kinds of instrument for the basis, it is characterized in that: the electronic circuit of this instrument be divided into simulate and the numeral two plates, simulating plate and be with the A/D conversion lcd drive chip of holding concurrently is core, the configuration operational amplifier, liquid crystal radix point driver and hummer chip for driving are formed, by placing function measurement range selection waver and the socket on the casing, the hole is finished combined-voltage and is measured, the alterating and direct current flow measurement, resistance capacitance is measured, crystal two, triode is measured, signal source simulates signal generation and analogue circuit signal tracing row barrier; The numeral plate is that the single-chip microcomputer with computer program stored and database is a core, the configuration address decoding scheme, frequency and logic state test circuit, data-latching circuit, IC chip test drives the digital signal source circuit of holding concurrently, expansion input port and digital circuit LCD driver are formed, by placing emulation button and the test jack hole on the casing, finish to simulate and measure with digital signal frequency, the digital signal logic state is measured, and digital circuit tracks and arranges barrier, digital integrated circuit chip off-line and on-line testing, line fault is test and the generation of signal source numeral signal automatically; The connection characteristics of each circuit are in the numeral plate; The single-chip data line connects the input end of data latches, output line of single-chip microcomputer is made power consumption control company data latches and is always exported the permission end, the single-chip microcomputer address wire connects the input of address decoding circuitry, the output of address decoding circuitry provides that multi-plate chip latchs trigger pip in the data latches, the output of data latches links to each other with the input of digital integrated circuit chip driver, each output of digital integrated circuit chip driver links to each other with digital integrated circuit chip test jack pin, each pin of test jack test chip links to each other with the input of expansion input port, the output of expansion input port links to each other with the single-chip microcomputer incoming line, interrupt line of single-chip microcomputer is made dormancy awakening and is linked to each other with the common junction of several emulation buttons, the other end of each emulation button is to link to each other with the single-chip microcomputer output line respectively, a sheet choosing of address decoding connects the digital circuit lcd drive chip, the single-chip microcomputer output line connects this chip data input and position input pin, frequency and the logic testing signal of measuring the jack base input send frequency and logic test circuit shaping and frequency division, the low-and high-frequency signal that decomposites connects single-chip microcomputer low-and high-frequency input port respectively, logic state is connected by the logic incoming line expands the input port, through the expansion mouthful the conversion after by single-chip microcomputer-incoming line collection, the power consumption line connects frequency and the logic state test circuit is done the high-impedance state differentiation, and the corresponding pin with test jack of single-chip microcomputer programmable signal edge output pin links to each other; Two liquid crystal display drive chip identical characters sections of analog-and digital-plate drive output pin and connect, the positive pin of simulation plate A/D chip power is supplied with after the voltage stabilizing current limliting by positive source, the negative pressure feeding that the negative pin of simulation plate A/D chip power is produced through the positive-negative power conversion chip by positive source, numeral plate lcd drive chip positive supply pin is supplied with after step-down by positive source, this chip negative supply pin ground connection also is connected to the electrolysis filtering circuit in the positive supply line of positive and negative power supply of A/D chip power and digital lcd chip power; The digital block plate is powered by placing the two wave band multipole switches single solution for diverse problems on the casing to change with the power supply that simulates plate, a power supply, then another piece outage, another cutter of this switch will switch the back electrode pin of two lcd drive chips of two plates synchronously, have only a chip back electrode to link to each other with the LCDs back electrode, the display screen back electrode links to each other with the stabilivolt negative pole, stabilivolt plus earth; Utilize the working time analysis-by-synthesis of program with each working signal in the numeral plate circuit, find out the signal multiplexing that does not coincide on time domain, they are: single-chip data output line (D
0～D
7) be the corresponding D of all output triggers of data-latching circuit
0～D
7Input pin is multiplexed, output line (AD
4) to connect button, shift register, LCD driver three tunnel multiplexing, output line (AD
1～AD
3) connect button, LCD driver two tunnel is multiplexing, output line (AD
5) connect shift register, LCD driver two tunnel is multiplexing, programmed signal source output pin (AD
0) gang socket, button, LCD driver three tunnel is multiplexing.
2, whole circuit test intelligence table according to claim 1, it is characterized in that the address decoding circuitry in the digital plate is a slice decoder chip, frequency and logic state test circuit are a slice Schmidt reshaper and a slice frequency divider, data-latching circuit is five ternary output triggers, the IC chip test digital signal source circuit of holding concurrently is three Darlington drivers, the expansion input port is two shift registers, and the amplifier that simulates in the plate is three amplifier chips.
3, intelligence table according to claim 1 and 2, it is characterized in that casing is provided with five multiplexing buttons of emulation, realize digital plate test operation to go into the machine conversational mode, it is multiplexing also to be provided with four test pencil jacks on the casing, switched synchronously with the power supply of two plates by two cuttves in the two wave band four blade switches on the casing, IC chip test and signal source accessory power outlet are multiplexing.
4, according to claim 1 or 2, it is characterized in that this instrument power is two kinds of dry cell and the outer stabilized voltage supply of machine in the machine, during the instrument on-line testing, with the external power supply power supply, this external power supply promptly is the power supply of equipment under test.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95240365 CN2263349Y (en) | 1995-08-21 | 1995-08-21 | Total circuit testing intelligence meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95240365 CN2263349Y (en) | 1995-08-21 | 1995-08-21 | Total circuit testing intelligence meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2263349Y true CN2263349Y (en) | 1997-09-24 |
Family
ID=33881961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95240365 Expired - Fee Related CN2263349Y (en) | 1995-08-21 | 1995-08-21 | Total circuit testing intelligence meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2263349Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102759646A (en) * | 2012-07-02 | 2012-10-31 | 优利德科技(中国)有限公司 | Testing method and device of harmonic wave universal meter |
| CN102841685A (en) * | 2011-06-24 | 2012-12-26 | 北京普源精电科技有限公司 | Measurement device with keyboard |
| CN105320065A (en) * | 2011-06-09 | 2016-02-10 | 恩格尔奥地利有限公司 | Operating unit for injection molding machine |
| CN105444816A (en) * | 2015-12-31 | 2016-03-30 | 天津芯慧鸿业科技发展有限公司 | Intelligent-type multipurpose instrument |
| CN110687334A (en) * | 2019-10-09 | 2020-01-14 | 中国南方电网有限责任公司超高压输电公司柳州局 | Relay protection error-proof digital multimeter |
-
1995
- 1995-08-21 CN CN 95240365 patent/CN2263349Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105320065A (en) * | 2011-06-09 | 2016-02-10 | 恩格尔奥地利有限公司 | Operating unit for injection molding machine |
| CN105320065B (en) * | 2011-06-09 | 2018-04-17 | 恩格尔奥地利有限公司 | Die casting machine operating unit |
| CN102841685A (en) * | 2011-06-24 | 2012-12-26 | 北京普源精电科技有限公司 | Measurement device with keyboard |
| CN102759646A (en) * | 2012-07-02 | 2012-10-31 | 优利德科技(中国)有限公司 | Testing method and device of harmonic wave universal meter |
| CN105444816A (en) * | 2015-12-31 | 2016-03-30 | 天津芯慧鸿业科技发展有限公司 | Intelligent-type multipurpose instrument |
| CN110687334A (en) * | 2019-10-09 | 2020-01-14 | 中国南方电网有限责任公司超高压输电公司柳州局 | Relay protection error-proof digital multimeter |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |