CA2072980C - Automated breakout box for automotive testing - Google Patents
Automated breakout box for automotive testing Download PDFInfo
- Publication number
- CA2072980C CA2072980C CA002072980A CA2072980A CA2072980C CA 2072980 C CA2072980 C CA 2072980C CA 002072980 A CA002072980 A CA 002072980A CA 2072980 A CA2072980 A CA 2072980A CA 2072980 C CA2072980 C CA 2072980C
- Authority
- CA
- Canada
- Prior art keywords
- voltage
- resistance
- providing
- multiplexer
- electrical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/005—Testing of electric installations on transport means
- G01R31/006—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks
- G01R31/007—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks using microprocessors or computers
Abstract
An automated test system (10) makes voltage and resistance measurements. A breakout cable (34) is connected between the vehicle electronic control module (30) and the vehicle sensors and controls (32). Resistance measurements are made between a selected pair of connector pins of the breakout cable (34) by connecting a current loop (50) which includes a power supply (56) and a known resistance (R1, R2) through a first multiplexing circuit (70, 72) to the selected pair of pins. A voltage measuring circuit (52) measures voltage across the known resistance (R1, R2) and between the pair of pins. The voltage measuring circuit (52) includes a second multiplexing circuit (82, 84) and a voltmeter (86, 88, 90, 92). The second multiplexing circuit (82, 84) receives inputs from the various pins, as well as from opposite sides of the known resistance (R1, R2) in the current loop (50).
The second multiplexing circuit (82, 84) provides its output to the voltmeter (86, 88, 90, 92) for measurement. By measuring the voltage across the known resistance (R1, R2), and the voltage between the selected pair of pins, the resistance between the two pins can be derived.
The second multiplexing circuit (82, 84) provides its output to the voltmeter (86, 88, 90, 92) for measurement. By measuring the voltage across the known resistance (R1, R2), and the voltage between the selected pair of pins, the resistance between the two pins can be derived.
Description
WO 92/08141 PU'T/US91 _1~
AU'fO~SA'TE;D BREAKOUT BOX FOR AIJTOPJIOTIVE TE~2'IAl_G
~3AG:1tGR0UND~F THE I1JV .NmTnu The present invention relates to an automated automotive teast system. In particular, the present invention is an automated :breakout box for performing test sequences on electrical systems of an automotive vehicle which include voltage and resistance measurements.
With the advent of integrated circuits, and with the increasing use of sophisticated electronic, electric and electromechanical sensors and control systems in automobiles, the testing and servicing of autamobiles has presented ever-increasing challenges.
At the present time, many tests of electrical systems, sensors and components of an automobile are made manually by a technician who unplugs a multipin connect~r between the vehicle's electronic control module (ECM) and the vehicle sensors and controls. The technician makes voltage and resistance measurements between various pins of the connector using a multia~eter. The technician making those measurements is required to m~nve the multimeter probe to appropriate measurement point. It is also necessary to set the multimeter to the proper measuring formula, such as volts or ohms.
This manual testing procedure has many drawbacks. In particular, the technician must follow detailed instructions in order to perform the proper tests. The instructions require that the technician set the proper condition, select the proper test points, read the equipment properly, and compare the reading to the listed tolerances specified in the instructions.
1'~1~ 92/08141 PC f/US91 /08317 -?_ Some test systems have been developed which simplify some of the test operations. These devices use selection switches to select the proper test points.
While this he~.ps to some ext:=_nt, the technician is still required to use the instrucaions, set the multimeter, and compare r~'adings to the listed tolerances for that measurement.
The Ballou et al. U.S. Patent 4,757,463 describes a computerized automotive vehicle diagnastic system in which a multiconductor probe cable is connected between the ACM and the vehicle sensors and controls. This cable is connected to a programmable cross-point switch, which is controlled by a ~nicrocontrolle:r. The cross-point switch is controlled to connect a amltime~ter, a voltage source and a ground selectively to points in order to perform a sequence of tests. These can include reading resistance, reading voltage, reading a pulse width modulated signal and reading the time in between two pulses.
As 'the number of electrical systems and sensors increa:;e, the number of possible combinations of points which need testing increases as well. An automated breakout box, therefore, would preferably make use of solid state switching devices to make connections between the testing circuitry and the points to be tested. Solid state multiplexers are available which are capable of selecting among a large number of different inputa or outputs. A solid state multiplexer offers significant advantages in size, cost and reliability over a multiplexer which makes use of electromechanical relays.
The ;problem with solid state multiplexers, however, is the internal resistance of the multiplexers WO 92/~D81~d1 PC'f/dJ~91/08317 zn~~~~o _. 3 in the ON state--which can typically be 75 ohms, and which varies with temperature, humidity, and other factors. Tn comparison, the contact resistance in electramechanical relay i.s much less, and is not affected to the same extent by temperature or humidity.
In certain applications, the internal resistance of solid state multiplexers is not a factor.
For example, in reading voltages, solid state multiplexers do not introduce a significant error, because the voltage measuring devices require high impedance input circuits (typically to megohms input impedance) , and therefore the internal resistance of the multiplexers does not affect accuracy of a voltage reading. This is not the case, however, in measuring resistances of the type encountered in the typical automobile. C>ften, the internal resistance of a solid state multiplexes is much greater than the resistance to be measured. P3easuring resistance of vehicle sensors and other control components requires the ability to make very precise resistance readings down to very low values (an thw~ order of a few ohms). Thesa readings must also be ;a~ade at low current levels, so that the test current being used does not damage the circuitry or components during the testing procedure.
The use of relays in a multiplexes overcomes the problem of internal resistance, but has other disadvantages. For example, with a 60-channel multiplexes (i.e., which is required to make measurements kaetween 60 pairs of contact points), a minimum of 120 relays is required. The resulting multiplexes isc bulky., costly and not as reliable as solid state multiplexers.
;~UMMAI2Y OF THF INVENTION
'fhe present invent ion cases a. first pair of multiplexers to connect a power supply and reference rF~:;ist~or to a selected pair of conner_tor points, and a second pair of mul.tiplexers to connect a voltage meas~_rrinq r_i.rw~it to the two connection points and to oppcasi.te sides of t:he reference resistor. By using separate mult:i_plexer~ for the current supply circuit and the voltage measuring circuit, the effects of internal 7_0 resistance of the multiplexers connected to the power supply is not a factor in the measurement of resistance.
The present invention, therefore, allows solid state muLt:iplFxers to be used, rathe r thar_ elPct-_.romechanical relays, without affecting the accuracy of resistance measurements.
Thei:ef.ore, in accordance with the present invention, there is provided a resistance measurement system for measuring resistances between a plurality of point:s, t:lze system compri.sinq:
?.0 a powPl- supply;
resistance means connected in a series circuit with t_he power supply;
first solid state multiplexes means having an indefinite internal resistance which varies with temperature, for connecting the series circuit to a selected pair of_ the points;
a voltmeter;
second solid state multiplexes means having an indefinite internal resistance which varies with temperature, for selectively c-onne~=:t: irug the vo)trneter to measure a first voi.tage across the resistance means and a second voltage between the selected pair of points; and C,A 0207298D 2001-03-21 -4a-means for deriving a resistance value based upon the measured 'first and second voltages.
Alsa in accordance with the present invention, there is provided an apparatus for performing a test sequence on a pl~_rrality o.E electrical components of a vehicle of a type having an electronic control module (gr,M) , t:he apparat~.~s c~ompri~ing:
means .for netriPVing the test: sequence;
7O) a mi.r_rocont.roller for executing the test sequence;
means for selectively isolating the ECM from the pli.lrality of electr_ ical. connections leading to the p7_ural_ity o.f eler_trical components;
a current ~av~pply comprising:
a power supply;
resistance means having a known resistance; and 2o first multiplexer means responsive to the microcontroller, for selectively 1°outing a current from the power supply through the resistance means and a pair of electrical connections 25 which lead to a selected electrical component of the plurality of electri_cval components;
a voltage rneas~rrincl circuit comprising:
means for sensing a voltage and providing 30 an output representative of the voltage to the microcontroller; and second multipl.exer means responsive to the m:icrocontroller, for selectively ;:wnnect i.ng t-he means for sensing a v«ltac~e to sense a first voltage -4b-across the resistance means and a second voltage across the pair of electrical connections;
means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
means for determining a condition of the selected eleC'tr~ical component based upon the second voltage and the magnitude of the current; and means for providing an output representative of t:he condition of the selected electrical component.
Sti...Ll. in accordance with the present invention, there is provided an automotive vehicle test apparatus for testing azi electrical system of an automotive veh:i.r_le, the electric:a:l system including an electronic ~~ont~rol rn«du.le connected to a plurality of electrical components by a plurality of conductors which form an electronic control module bus for carrying electronic signals between the electronic control module and the pli.zrality of electrical components, the test apparatus comprising:
a mul~ipin connector adapted for connecting to t_he electronic control module bus whereby access to the plurality of conductors is provided to the test apparatus;
a first mult;iplexer coupled to the multipin connec:i~or for selectively providing a current path between a pair of conductors c~f_ th<~ electronic control bus;
a second multiplexer coupled to the multipin connector and having a pair of outputs CA 0?072980 2001-03-21 _q~_ selectively connected across a pair of conductors of the electronic control bus;
means for sensing voltage across the outputs of the second multiplexer and providing a representative digital output; and cont:.roller means for instructing the first multiEnl.exer to provide a current path betweE:n a pair of conductors of the electronic control bus, 7.rlStructlng the p second multiplexer to connect the pair of output=> to a pair of conductors of the elect, z:onic control bus, receiving the riigitti 1. out:put from the means for sensing volt:acte, performing a test based upon the digital output and providing an output based ~_ipon results of the test .
Still further in accordance with the present invention, there is provided a method for performing a re st: sc~q»~ncE: orl a pl~zrality of electrical components in 2.(7 a v~hic~l ~: of a type having an electronic control module, the method compri~inc3;
retrieving the test sequence;
iso7_ating the electronic control module from the plurality of electrical components;
routing a current through a known resistance and a ~elected component of the plurality of components;
sensing a first voltage across the known resi9.r_ance and a second voltage across the seler.red component;
caeterm:ining a magnitude of the current based upon the f_ i.rst vol tape and the known resistance;
cue. 02072980 2001-03-21 -4d-determining a condition of the selected component based t.zpon the second voltage and the magnitude of the current; and providing an output representative of the condition of the selected electrical component.
Stlll further in accordance with the present invention, there is provided a method for performing a test sequence on a p7.urality of_ el.ectrical components in a vehic..le of a type having an electronic control module, the method comprising:
retrieving t:he test sequence;
isolating the electronic control module from the plurality of electrical components;
75 providing access to a plurality of electrical ~::onnec~t:ions which lead to the electrical COtTtpr~l7E?ntS ;
routing a current through a known resistance and a first set of electrical connections of. the plurality of electrical conne<:tions ;
sensing a voltage across a second set of electrical connections of the plurality of electr_~ical connections;
deriving a quantity representative of cross-talk based upon the first and second sets <xnd the sensed voltage; and providing an output representative of cross--talk.
Sti.:l.l f.urt.her in accordance with the present invention, there is provided an apparatus for performing a test sequence on a plurality of electrical components of a vehicle of a type having an electronic control module (F.CM), the apparatus comprising:
means for retrieving the test sequence;
ca ozo~zseo zoos-os-zi -4e-a microcontroller for executing the test sequence;
means for seler_t:ive7y iso7_ating the ECM from the plurality of electrical connections leading to the plurality of electrical r_omponents;
a current :>upply comprising:
a poweer supply;
resistance means having a known l0 resistance; and first mulr_iplexer means responsive to the microcontroller, f_or selectively routing a current from the power supply through the resistance means 75 and a pair of electrical connections which lead to a selected electrical component of the plurality of electrical components;
a voltage measuring circuit comprising:
20 means for sensing a voltage and providing <~n output representative of the ,.roltage to the microcontroller; and second multiplexer means responsive to the microcontroller, for selectively 25 connecting the means for sensing a voltage to sense a first voltage across the resistance means and a second voltage across the pair of electrical connections;
30 means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
means for determining a condition of the 35 selecr_ed electrical component based upon -4f-the second voltage and the magnitude of the current; and means for providing an output representative of the condition of the selected electrical component.
Sti7.1 further in accordance with the present invention, there is provided a method for performing a test sequence on a plurality of electrical components in a vehicle of a type haring an electronic control module, t: he method compri.sin~t;
7.0 retrieving the test sequence;
isolating the electronic control. module from the plurality of electrical components;
providing a first select signal to a first multiplexes to route a current through a known resistance and a selected component of the plurality of components;
providing a second select signal t.o a second multipl.exer to sense a first voltage acros.~ the known resistance;
providing a third select signal to the second multiplexes to sense a second voltage :~cr_oss the se).ected component;
determining a magnitude of the current based upon the first voltage and the known resistance;
determiziin<3 a condition of the selected component based upon the second voltage and the magnitude of the current; and providing an output representative of the c:ondit~:ion of the selected electrical component.
Still further in accordance with the present invention, there is provided a method for performing a test sequence on a plurality of electrical components in _qg_ a vehicle of a type having an electronic control module, the method comprising;
retrieving the test sequence;
i.solatinq the e7ectrpnic control module from the p7~~ralit.y of electrical components;
pro,ridinct ~~ccess to z plurality of electrical connections which lead to the electrical components;
cont.rol.ling a fi.r_st mult_ipJexer to route a current through a known resistance and a first set of ele_rr_rica7 connections of the plurality of electrical connections;
controllinct a second multiplexes to sense a voltage across a second set of electrical 1~; connec:tions of the plurality of electrical connections;
deriving a. quantity representative of cross-talk based upon the first and second sets and the sensed voltage; and providing an output representative of cross--talk, BRIEF DESCRIPTION OF THE DRAWINGS
Figuze 1 :is an electrical block diagram of an aut..«matE~c.i bxeakout box of t:he present invention_ Figirr_e ?. is an electrical block diagram of the analog processing anal control circuitry of the automated 1oreakout. box of Figure 1.
Figure 3 is a simplified block diagram illustratpng the re~;istance measurement circuitry of the prE.,v;ent: irment:ion.
DfTI~IL~ED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figc.m t. 1. shows automated breakout box 10 of the present invention, which includes digital computer 12, control and analog processing circuitry 14, power supply 16, memory 1E3, vehicle scanner 20, user input/output 22 -4h-(which includes keyboard 22A and display 22B), and external communication r_ircuitry 74. Automated breakout box 1.o i s connected to an automobile through control and analog processing circ~~i.t..r_y 74, and ~D'O 92/0~H 41 ~'CTI US91 /Oi331 "7 _. 5 _ performs sequential testing of a variety of different systems and components, such as the electronic Control module (ECI~) .and related vaahie:le sensors and controls, the fuel injeeaion system, instrument panel displays and indicators, a,nd the anti-lock braking system (AES).
Under the control of computesr 12 , automated breakout bnx to sets up the conditions for testing, does the test, records the tEat results, and supplies the test results to the operator/technician through the user display 22B
l0 to permit the results of the test to be reviewed.
Comgauter 12 is preferably a microprocessor-based computes.- system. Computer 12 provides control signals to cowtrol and analog processing circuitry 14 to set up circuitry 14 to make particular tests. In Preferred embodiments of the present invention, circuitry 14 measures voltages, resistances, and pulse widths, and provides to computer 12 digital data which represents the measured values. As will be described in further detaiaL with reference to Figures 2 and 3, 2o control and analog processing circuitry 14 is capable of connection to the °~lectrical system of an automobile, and can measursa voltages and resistance between a large number of individual connector points.
Power supply 16 provides power to computer 12 arid to memory e18.
Memoa~y 18 preferably includes RAM, RoM, and EPROM storage for use by computer 12. The programs which operate <:omputer 12 can be stored in memory 18.
In addition, the specifications of the particular vehicle to be tested, including the particular pins to be accessed and the sequence,of tests to be performed, is provided to computer 12 from memory 18. this allows the test to preaceed automatically, without a need for the technician to read and follow a length procedure in a printed manual. Because there are a large number of different vehicles, each with a unique set of connectors and test sequences, memory 18 preferably includes storage devices such as memory cards, memory cartridges, magnetic floppy disks, optical disks, or the like, which store all of the necessary information for a particular vehicle.
Depending on the vehicle to be used, a selected storage device for that vehicle is inserted into memory 18, which includes an appropriate card reader, cartridge reader, disk drive or the like.
Vehicle scanner 20 is a device which can connect to a readout plug on a vehicle to obtain fault code information from the vehicle. For General Motors*
cars, the connector for fault code information is known as the ALDL connector. The fault code obtained by vehicle scanner 20 is supplied to computer 12, and is used to direct the testing to particular systems and components and to particular test sequences.
User I/O 22 preferably includes keyboard 22A
and display 22B. The operator/technician provides information about the particular vehicle to be tested and the tests which are desired, and responds to prompts from computer 12 which are supplied to the display 22B.
As part of the automated testing procedure, information is supplied through display 22B to the operator/technician, indicating the test conditions which must be set. For example, in some tests the vehicle's ignition must be on, while in another test the ignition must be off. Similarly, some tests require that devices be moved (such as rotating the throttle plate to see if the resistance values are in the right range). Other tests require that the engine be running.
*: Trade-Mark Display 22B, under the control of computer 12, provides the necessary prompts and setup information to the operator/technician.
In addition, display 22B provides the operator/technician with the results of the test such as the test sequence number, the value read, the tolerance required by that particular test, and good or bad indication.
External communication circuitry 24 allows computer 12 to communicate with other computers and systems. In one preferred embodiment, external communication circuitry 24 includes Controller Area Network (CAN) and RS232 communication capabilities.
Figure 2 shows control and analog processing circuitry 14, which is used to make voltage and resistance measurements and to measure pulse width. In Figure 2, vehicle ECM 30 and vehicle sensors and controls 32 are shown. Connection to ECM 30 and to vehicle sensors and controls 32 is made by breakout cable 34, which includes multipin connector 36 for connection to ECM 30, multipin connector 38 for connection to sensors and controls 32, and multipin connector 40 for connection to adaptor 42. The particular configuration of connector pins for vehicle ECM 30 and vehicle sensors and controls 32 will differ depending upon the manufacture and in some cases the model of vehicle. Breakout cable 34 is one of several different cables available to the technician, and is arranged to mate with a particular manufacturer's ECM
30 and sensors and controls 32.
Adaptor 42 provides a connection between connector 40 of breakout cable 34 and universal multipin connector 44 of circuitry 14. The operator/technician wo 9zios»' ~cTiu~~~io~~»
has available: a number of different breakout cables 34 and adaptors 42 to allow circuitry 14 to be used with a variety of d9.fferent manufacturers vehicles.
Universal connector 44 mates with adaptor 42, and provides jthe connection between the test circuits of control and analog processing circuitry 14 and the electrical system or component which is being tested.
In one preferred embodiment of the present invewtian, universal connector 44 as a 120-pin connector which has a separate ground wire 46 and allegator clamp 48 far connection to vehicle ground.
Connected to universal connector 44 is resistance m~:asuring current supply circuit 5o and voltage measuring circuit 52. Control and analog processing circuitry 14 also includes flying lead circuitry 54, aahich allows measurement between any tyro points independent of universal connector 44.
Current supply circuitry 50 includes power supply 56, pr~:cision resistors R1 and R2, relay contact 5~A and relay coil S~B, multiplexers 70 and 72 and interface 74. In a preferred embodiment of the present invention, a power supply 56 is a constant current power supply which operates at about l0 volts and supplies a 10 milliamp constant current. i~ultiplexers 70 and 72 are 64:1 multi.plexers.
The current I+ from terminal 76 of power supply 56 is :9upplied to input 70A of multiplexer 70.
Based upon a control signal from interface 74, multiplexer 70 supplies current I+ to one of its outputs, which include sixty output lines 70B which are connected to connector 44 and output line 7oC which is connected to flying lead circuitry 54. When cable 34 is being used, this causes current I+ to be steered to one Wta 92/081:13 fCr/1J591/f98317 2~"12~~~
_g_ of sixty diff~arent connection points through connector 44, adaptor 42, and cable 34. Return current I- from vehicle sensors and controls 32 is supplied through breakout cable 34 and connector 40 to adaptor 42 and then to universal connector 44. It is returned on one of sixty i~aput lines 72A to multiplexes 72.
Alternatively,, return current is returned on input line 72B from flying lead circuit 54. Interface 74 supplies a signal to n~ultiplexer 72 which selects one of the l0 input lines 72A, 72B, and routes the return current I-through output line 72C to resistor R2. rrhe return current I- flows through resistor R2 and through either resistor R1 or' relay contacts 54, depending on whether shunt relay coil 58B is energized or de-energized. The return current: I- then flows to terminal 78 of power supply 56.
Interface 74 receives signals from computer 12 and selects the particular connector to which and from which current is supplied by the resistance measuring current laop. Interface 74 also selects the range of operation by selecting whether resistor R1 will be connected in s~:rie~ with resistor R2 or will be shunted by relay contacts 58A. In one preferred embodiment of the present invention, R1 is a LOOK ohm resistor, while resistor R2 is a 200 ohm resistor.
t7olta~ge measuring circuit 52 includes electrostatic discharge (ESD) protection and scaling circuitry 80, multiplexers 82 and 84, operational amplifier 86, sample/hold and peak-to-peak detector circuit 88, autea-ranging circuitry 90, analog-to-digital (A/D) conv~ertor~ 92, pulse width tuner g4, and interface circuit g6.
ENO 9?/08141 fC1'I C1S91 /0831'7 zo l~~~o _10_ Mu:ltiplexers 82 ;and 84 are 64:1 multiplexers which receiv:~ a plurality of input lines, and provide one output line each. Sixty input lines 82A to multiplexes 82 are supplied through ESD protection and scaling circuit 80. These sixty input lines 82A are connected to the same sixty pins of connector 44 as output lines 70B of multiplexes 70. In addition, multiplexes 82 receives input line 82B, which is connected to terminal 78 of power supply 56. The VA
l0 output of flying lead circuitry 54 (which will be described in further detail later) is also supplied on input line 82C to multiplexes 82. Vehicle ground line 100 (which is connected to ground wire 46 and allegator clamp 48) is ;supplied as an input to multiplexes 82 and multiplexes 84, R3ultiplexer 84 receives sixty input lines 84A
from ESD protection and scaling circuit 80 which are connected to the same sixty pins of connector 44 as input lines 7;2A of multiplexes 72.
Multiplexes 84 also receives input line 84B
which is connected to output line 72C of multiplexes 72.
It also receives-''the VB output from flying lead circuitry 54 on input line 84C.
Mult:iplexers 82 and 84 are controlled by interface 96, which receives control signals from computer 12. :Lnterface 96 also supplies control signals which determine whether A/D convertor S2 or pulse width timer 94 sa~ill be supplying data on lines 104.
Output lines 82D and 84D of multiplexers 82 and 84 are ccannected to the inverting (-) and non investing (.+) inputs of operational amplifier 86, respectively. The output of operational amplifier 86 is supplied to both sample/hold and peak-to°peak detector WO 9?/08141 P0.°T/L1~i91/08317 circuit 88 and also to pulse width timer 94. The output of sample/holti and peak-to-peak detector circuit 88 is supplied to the auto-ranging circuitry 90 of A/D
convertor 92. When A/D convertor 92 is selected by interface 96, it converts the analog voltage which receives at its input to a 12-bit digital value which is supplied on l~.nes 104.
Pulse width timer 94, when selected by interface 96, receives the output of operational l0 amplifier 86 and times the pulse width of the signal received. The measured pulse width is supplied as digital data on lines 104 to computer 12.
Flying lead circuitry 54 includes flying lead interface 110, connector 112, and a pair of probes 114 and 116. Function generator 118 is also connected to flying lead interface 110.
Interface 74 provides a general purpose control line 1::0 which selects operation through flying lead circuit 54, rather than through breakout cable 34, adaptor 42, and universal connector 44> When selected, flying. leads probes.114 and 116 are used to contact selected leads or pins. Various voltage and resistance measurements can be made which are similar to the measurements made through sable 34. Resistance measurements current is provided to and from flying lead interface 110 through lines 70C and 72B which are connected to a~ultiplexers 70 and 72, together with voltage output lines 126 and 128 which supply the VA and VB output voltages to multiplexers 82 and 84.
3o Voltage measurements are made by circuit 14 through the use of voltage measuring circuitry 52.
Computer 12 selects, through interface 96, the two connector points of universal connector 44 which are to WO '~2/OBId 1 PC°T/~JSII /Of3317 be connected 'to A/D convertor 92. This selection is done through multiplexers 82 and 84. The output voltages from mul~tiplexers 82 and 84 are supplied on lines 82D and. 84D to operational amplifier 86, and through samplejhold and peak-to-peak detector circuitry 88 and auto-rangincy circuitry 90 to the input of AJD
convertor 92.
If additional voltages are to be measured, computer 12 c.'hanges the control signals supplied to interface 96, which causes multiplexers 82 and 84 to select other pins for connection to operational amplifier 86.
The same voltage measurements can be made through flying lead circuit 54. Interface 74 provides a control signal on line 120 to flying lead interface 110. The VA and VB voltages supplied on input lines 82C
and 84C of mult.iplexers 82 and 84, and are connected to output lines 82D and 84D and thus to the inputs of operational amplifier 86.
6dhen resistance measurements are to be made, both current supply circuit 50 and voltage measuring circuit 52 are active. Normally, breakout cable 34 will be connected only to vehicle sensors and controls 32 during a resistance measurement test. This avoids having a component within the vehicle ECM affecting the resistance measurement. During a voltage measurement, on the other hand, both ECM 30 and vehicle sensors and controls 32 are normally connected to breakout cable 34.
Power supply 5~, which is preferably a constant c~arrewt source providing current at a level of about 10 mill:iamps and nominally about ~.0 volts, supplies cLlrrent: I+ through multiplexer 70 to one of the sixty lines 70B to connector 44. The return current I°
WO 92/x8141 f('f/US91/08317 ~13-is supplied vrom connector 44 to one of the sixty input lines 721 of multiplexer 72, and then from output line 72C through one or both the resistors R1 and R2.
Computer 12 selects, through interface 74 and shunt relay coil 588, whether resistor Ftl will be shunted by contacts 58A.
When the resistance measuring made is first selected, multiplexers 82 and 84 are controlled to connect the selected two pins of connector 44 to the l0 inputs of operational amplifier 86. At this time, current is not yet being supplied through multiplexers 70 and 72, and therefore no voltage should appear between the + and ~ inputs of operational amplifier 86.
Tf a voltage does appear, the data on lines 104 to computer 12 will indicate the presence of the non~zero voltage, and <:amputer 12 will stop and provide a message through display 22B. Computer 12 will not allow a resistance measurement to continue until the operator/technician supplies an input through keyboard 22A indicating that the condition has been corrected.
Typically, this situation will occur because 8~ 30 has nat been disconnected from breakout cable 34.
Tf no voltage appeared on the selected pins, computer 12 will instruct multiplexers 70 and 72 to select the ;game two pins which are selected by multiplexers 82 and 84. Circuitry 14 is then ready to perform the raseietxncs check.
~iultiplexers 82 and 84 are instructed to set measuring points to lines 82B and 848. The voltage reading between these two lines represents the voltage across resistors R1 and R2. Since the resistance between ii.nes 828 and 84B is knawn (i.e., either R1 + R2 or just ~t2), the voltage reading which is obtained WO 9?/08141 P(:T/iJS91/08~1'7 _14_ provides an ;indication of the current which is flowing through the current loop.
Co~uputep 12 then instruct, a~ultiplexers 82 and 84 to read ~:he voltage across the pre-selected pins.
Since the current was known by the previous measurement, computer 12 is able to derive the resistance by measuring the: voltage between the two pins and dividing that voltage by the current which had just been read.
This method allows the reading of very small resistances very accurately. The internal resistances of multiplex~:rs 70, 72, 82 and 84 do not affect the accuracy of the measurement. As a result, the present invention allows the use of solid state multiplexers which are substantially lower cost, more reliable, and more compact than relays.
Figure 3 shows a simplified version of the resistance measurement circuitry shown in Figure 2. In Figure 3, digital voltmeter 150 represents the circuitry formed by operational amplifier 86, sample/hold and peak-to-peak detector circuitry 88, auto~ranging circuitry 90, and A/D convertor 92. Tn addition, the diagram is simplified by not showing ljreakout cable 3~, adaptor 42, universal connector 4~ and flying lead circuitry 54. The resistance to be measured is referred to R~r the voltage across resistors E1 and R1 is Eg, and the voltage across resistor Rx is Ex.
)luring the first measurement, the voltage Eg is read by digital voltmeter 150 through multiplexers 82 and 84. The current I~ is:
WO 92/08141 1'CT/11591/t18317 Es '~X~ ~z+R2 Eq. 1 In the next step of the process, digital voltmeter 150 reads voltage Ex. Since Ix is already known and Ex is measured, resistance Rx can be determined by:
E
Rx~ l.x Eq . 2 x The internal resistances of multiplexers 70 and 72 are not involved in these readings. Ee is measured dires:tly across resistors Rl and R2, and Ex is measured directly across Rx. Multiplexers 70 and 72 simply steer the current Ix to and from resistor Rte, but are not involved in the voltage measurements from which resistance R~ is derived.
The internal resistances of multiplexers 82 and 84 also do not affect the voltage readings because those resirtances (approximately 75 ohms) are very small compared to the high input impedance (typically 10 megohans) of digital voltmeter 150.
The resistance measuring technique of the present invention offers another unique capability for breakout box :10. It is possible, with the present invention, to measure cross-talk between various lines and sensors. This can be done by supplying current '~O 92/08141 PCT/U591/0$~17 2D ~~~~0 ms~
through multpiplexers 70 and 72 to one set of pins, and then measuring voltages through multiplexers 82 and 84 on different sets of pins.
~.lt:hough the present invention has been described with reference to preferred embodiments, workers skil7.ed in the art will recognize that changes may be made an form and detail without departing from the spirit and scope of the invention.
AU'fO~SA'TE;D BREAKOUT BOX FOR AIJTOPJIOTIVE TE~2'IAl_G
~3AG:1tGR0UND~F THE I1JV .NmTnu The present invention relates to an automated automotive teast system. In particular, the present invention is an automated :breakout box for performing test sequences on electrical systems of an automotive vehicle which include voltage and resistance measurements.
With the advent of integrated circuits, and with the increasing use of sophisticated electronic, electric and electromechanical sensors and control systems in automobiles, the testing and servicing of autamobiles has presented ever-increasing challenges.
At the present time, many tests of electrical systems, sensors and components of an automobile are made manually by a technician who unplugs a multipin connect~r between the vehicle's electronic control module (ECM) and the vehicle sensors and controls. The technician makes voltage and resistance measurements between various pins of the connector using a multia~eter. The technician making those measurements is required to m~nve the multimeter probe to appropriate measurement point. It is also necessary to set the multimeter to the proper measuring formula, such as volts or ohms.
This manual testing procedure has many drawbacks. In particular, the technician must follow detailed instructions in order to perform the proper tests. The instructions require that the technician set the proper condition, select the proper test points, read the equipment properly, and compare the reading to the listed tolerances specified in the instructions.
1'~1~ 92/08141 PC f/US91 /08317 -?_ Some test systems have been developed which simplify some of the test operations. These devices use selection switches to select the proper test points.
While this he~.ps to some ext:=_nt, the technician is still required to use the instrucaions, set the multimeter, and compare r~'adings to the listed tolerances for that measurement.
The Ballou et al. U.S. Patent 4,757,463 describes a computerized automotive vehicle diagnastic system in which a multiconductor probe cable is connected between the ACM and the vehicle sensors and controls. This cable is connected to a programmable cross-point switch, which is controlled by a ~nicrocontrolle:r. The cross-point switch is controlled to connect a amltime~ter, a voltage source and a ground selectively to points in order to perform a sequence of tests. These can include reading resistance, reading voltage, reading a pulse width modulated signal and reading the time in between two pulses.
As 'the number of electrical systems and sensors increa:;e, the number of possible combinations of points which need testing increases as well. An automated breakout box, therefore, would preferably make use of solid state switching devices to make connections between the testing circuitry and the points to be tested. Solid state multiplexers are available which are capable of selecting among a large number of different inputa or outputs. A solid state multiplexer offers significant advantages in size, cost and reliability over a multiplexer which makes use of electromechanical relays.
The ;problem with solid state multiplexers, however, is the internal resistance of the multiplexers WO 92/~D81~d1 PC'f/dJ~91/08317 zn~~~~o _. 3 in the ON state--which can typically be 75 ohms, and which varies with temperature, humidity, and other factors. Tn comparison, the contact resistance in electramechanical relay i.s much less, and is not affected to the same extent by temperature or humidity.
In certain applications, the internal resistance of solid state multiplexers is not a factor.
For example, in reading voltages, solid state multiplexers do not introduce a significant error, because the voltage measuring devices require high impedance input circuits (typically to megohms input impedance) , and therefore the internal resistance of the multiplexers does not affect accuracy of a voltage reading. This is not the case, however, in measuring resistances of the type encountered in the typical automobile. C>ften, the internal resistance of a solid state multiplexes is much greater than the resistance to be measured. P3easuring resistance of vehicle sensors and other control components requires the ability to make very precise resistance readings down to very low values (an thw~ order of a few ohms). Thesa readings must also be ;a~ade at low current levels, so that the test current being used does not damage the circuitry or components during the testing procedure.
The use of relays in a multiplexes overcomes the problem of internal resistance, but has other disadvantages. For example, with a 60-channel multiplexes (i.e., which is required to make measurements kaetween 60 pairs of contact points), a minimum of 120 relays is required. The resulting multiplexes isc bulky., costly and not as reliable as solid state multiplexers.
;~UMMAI2Y OF THF INVENTION
'fhe present invent ion cases a. first pair of multiplexers to connect a power supply and reference rF~:;ist~or to a selected pair of conner_tor points, and a second pair of mul.tiplexers to connect a voltage meas~_rrinq r_i.rw~it to the two connection points and to oppcasi.te sides of t:he reference resistor. By using separate mult:i_plexer~ for the current supply circuit and the voltage measuring circuit, the effects of internal 7_0 resistance of the multiplexers connected to the power supply is not a factor in the measurement of resistance.
The present invention, therefore, allows solid state muLt:iplFxers to be used, rathe r thar_ elPct-_.romechanical relays, without affecting the accuracy of resistance measurements.
Thei:ef.ore, in accordance with the present invention, there is provided a resistance measurement system for measuring resistances between a plurality of point:s, t:lze system compri.sinq:
?.0 a powPl- supply;
resistance means connected in a series circuit with t_he power supply;
first solid state multiplexes means having an indefinite internal resistance which varies with temperature, for connecting the series circuit to a selected pair of_ the points;
a voltmeter;
second solid state multiplexes means having an indefinite internal resistance which varies with temperature, for selectively c-onne~=:t: irug the vo)trneter to measure a first voi.tage across the resistance means and a second voltage between the selected pair of points; and C,A 0207298D 2001-03-21 -4a-means for deriving a resistance value based upon the measured 'first and second voltages.
Alsa in accordance with the present invention, there is provided an apparatus for performing a test sequence on a pl~_rrality o.E electrical components of a vehicle of a type having an electronic control module (gr,M) , t:he apparat~.~s c~ompri~ing:
means .for netriPVing the test: sequence;
7O) a mi.r_rocont.roller for executing the test sequence;
means for selectively isolating the ECM from the pli.lrality of electr_ ical. connections leading to the p7_ural_ity o.f eler_trical components;
a current ~av~pply comprising:
a power supply;
resistance means having a known resistance; and 2o first multiplexer means responsive to the microcontroller, for selectively 1°outing a current from the power supply through the resistance means and a pair of electrical connections 25 which lead to a selected electrical component of the plurality of electri_cval components;
a voltage rneas~rrincl circuit comprising:
means for sensing a voltage and providing 30 an output representative of the voltage to the microcontroller; and second multipl.exer means responsive to the m:icrocontroller, for selectively ;:wnnect i.ng t-he means for sensing a v«ltac~e to sense a first voltage -4b-across the resistance means and a second voltage across the pair of electrical connections;
means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
means for determining a condition of the selected eleC'tr~ical component based upon the second voltage and the magnitude of the current; and means for providing an output representative of t:he condition of the selected electrical component.
Sti...Ll. in accordance with the present invention, there is provided an automotive vehicle test apparatus for testing azi electrical system of an automotive veh:i.r_le, the electric:a:l system including an electronic ~~ont~rol rn«du.le connected to a plurality of electrical components by a plurality of conductors which form an electronic control module bus for carrying electronic signals between the electronic control module and the pli.zrality of electrical components, the test apparatus comprising:
a mul~ipin connector adapted for connecting to t_he electronic control module bus whereby access to the plurality of conductors is provided to the test apparatus;
a first mult;iplexer coupled to the multipin connec:i~or for selectively providing a current path between a pair of conductors c~f_ th<~ electronic control bus;
a second multiplexer coupled to the multipin connector and having a pair of outputs CA 0?072980 2001-03-21 _q~_ selectively connected across a pair of conductors of the electronic control bus;
means for sensing voltage across the outputs of the second multiplexer and providing a representative digital output; and cont:.roller means for instructing the first multiEnl.exer to provide a current path betweE:n a pair of conductors of the electronic control bus, 7.rlStructlng the p second multiplexer to connect the pair of output=> to a pair of conductors of the elect, z:onic control bus, receiving the riigitti 1. out:put from the means for sensing volt:acte, performing a test based upon the digital output and providing an output based ~_ipon results of the test .
Still further in accordance with the present invention, there is provided a method for performing a re st: sc~q»~ncE: orl a pl~zrality of electrical components in 2.(7 a v~hic~l ~: of a type having an electronic control module, the method compri~inc3;
retrieving the test sequence;
iso7_ating the electronic control module from the plurality of electrical components;
routing a current through a known resistance and a ~elected component of the plurality of components;
sensing a first voltage across the known resi9.r_ance and a second voltage across the seler.red component;
caeterm:ining a magnitude of the current based upon the f_ i.rst vol tape and the known resistance;
cue. 02072980 2001-03-21 -4d-determining a condition of the selected component based t.zpon the second voltage and the magnitude of the current; and providing an output representative of the condition of the selected electrical component.
Stlll further in accordance with the present invention, there is provided a method for performing a test sequence on a p7.urality of_ el.ectrical components in a vehic..le of a type having an electronic control module, the method comprising:
retrieving t:he test sequence;
isolating the electronic control module from the plurality of electrical components;
75 providing access to a plurality of electrical ~::onnec~t:ions which lead to the electrical COtTtpr~l7E?ntS ;
routing a current through a known resistance and a first set of electrical connections of. the plurality of electrical conne<:tions ;
sensing a voltage across a second set of electrical connections of the plurality of electr_~ical connections;
deriving a quantity representative of cross-talk based upon the first and second sets <xnd the sensed voltage; and providing an output representative of cross--talk.
Sti.:l.l f.urt.her in accordance with the present invention, there is provided an apparatus for performing a test sequence on a plurality of electrical components of a vehicle of a type having an electronic control module (F.CM), the apparatus comprising:
means for retrieving the test sequence;
ca ozo~zseo zoos-os-zi -4e-a microcontroller for executing the test sequence;
means for seler_t:ive7y iso7_ating the ECM from the plurality of electrical connections leading to the plurality of electrical r_omponents;
a current :>upply comprising:
a poweer supply;
resistance means having a known l0 resistance; and first mulr_iplexer means responsive to the microcontroller, f_or selectively routing a current from the power supply through the resistance means 75 and a pair of electrical connections which lead to a selected electrical component of the plurality of electrical components;
a voltage measuring circuit comprising:
20 means for sensing a voltage and providing <~n output representative of the ,.roltage to the microcontroller; and second multiplexer means responsive to the microcontroller, for selectively 25 connecting the means for sensing a voltage to sense a first voltage across the resistance means and a second voltage across the pair of electrical connections;
30 means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
means for determining a condition of the 35 selecr_ed electrical component based upon -4f-the second voltage and the magnitude of the current; and means for providing an output representative of the condition of the selected electrical component.
Sti7.1 further in accordance with the present invention, there is provided a method for performing a test sequence on a plurality of electrical components in a vehicle of a type haring an electronic control module, t: he method compri.sin~t;
7.0 retrieving the test sequence;
isolating the electronic control. module from the plurality of electrical components;
providing a first select signal to a first multiplexes to route a current through a known resistance and a selected component of the plurality of components;
providing a second select signal t.o a second multipl.exer to sense a first voltage acros.~ the known resistance;
providing a third select signal to the second multiplexes to sense a second voltage :~cr_oss the se).ected component;
determining a magnitude of the current based upon the first voltage and the known resistance;
determiziin<3 a condition of the selected component based upon the second voltage and the magnitude of the current; and providing an output representative of the c:ondit~:ion of the selected electrical component.
Still further in accordance with the present invention, there is provided a method for performing a test sequence on a plurality of electrical components in _qg_ a vehicle of a type having an electronic control module, the method comprising;
retrieving the test sequence;
i.solatinq the e7ectrpnic control module from the p7~~ralit.y of electrical components;
pro,ridinct ~~ccess to z plurality of electrical connections which lead to the electrical components;
cont.rol.ling a fi.r_st mult_ipJexer to route a current through a known resistance and a first set of ele_rr_rica7 connections of the plurality of electrical connections;
controllinct a second multiplexes to sense a voltage across a second set of electrical 1~; connec:tions of the plurality of electrical connections;
deriving a. quantity representative of cross-talk based upon the first and second sets and the sensed voltage; and providing an output representative of cross--talk, BRIEF DESCRIPTION OF THE DRAWINGS
Figuze 1 :is an electrical block diagram of an aut..«matE~c.i bxeakout box of t:he present invention_ Figirr_e ?. is an electrical block diagram of the analog processing anal control circuitry of the automated 1oreakout. box of Figure 1.
Figure 3 is a simplified block diagram illustratpng the re~;istance measurement circuitry of the prE.,v;ent: irment:ion.
DfTI~IL~ED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figc.m t. 1. shows automated breakout box 10 of the present invention, which includes digital computer 12, control and analog processing circuitry 14, power supply 16, memory 1E3, vehicle scanner 20, user input/output 22 -4h-(which includes keyboard 22A and display 22B), and external communication r_ircuitry 74. Automated breakout box 1.o i s connected to an automobile through control and analog processing circ~~i.t..r_y 74, and ~D'O 92/0~H 41 ~'CTI US91 /Oi331 "7 _. 5 _ performs sequential testing of a variety of different systems and components, such as the electronic Control module (ECI~) .and related vaahie:le sensors and controls, the fuel injeeaion system, instrument panel displays and indicators, a,nd the anti-lock braking system (AES).
Under the control of computesr 12 , automated breakout bnx to sets up the conditions for testing, does the test, records the tEat results, and supplies the test results to the operator/technician through the user display 22B
l0 to permit the results of the test to be reviewed.
Comgauter 12 is preferably a microprocessor-based computes.- system. Computer 12 provides control signals to cowtrol and analog processing circuitry 14 to set up circuitry 14 to make particular tests. In Preferred embodiments of the present invention, circuitry 14 measures voltages, resistances, and pulse widths, and provides to computer 12 digital data which represents the measured values. As will be described in further detaiaL with reference to Figures 2 and 3, 2o control and analog processing circuitry 14 is capable of connection to the °~lectrical system of an automobile, and can measursa voltages and resistance between a large number of individual connector points.
Power supply 16 provides power to computer 12 arid to memory e18.
Memoa~y 18 preferably includes RAM, RoM, and EPROM storage for use by computer 12. The programs which operate <:omputer 12 can be stored in memory 18.
In addition, the specifications of the particular vehicle to be tested, including the particular pins to be accessed and the sequence,of tests to be performed, is provided to computer 12 from memory 18. this allows the test to preaceed automatically, without a need for the technician to read and follow a length procedure in a printed manual. Because there are a large number of different vehicles, each with a unique set of connectors and test sequences, memory 18 preferably includes storage devices such as memory cards, memory cartridges, magnetic floppy disks, optical disks, or the like, which store all of the necessary information for a particular vehicle.
Depending on the vehicle to be used, a selected storage device for that vehicle is inserted into memory 18, which includes an appropriate card reader, cartridge reader, disk drive or the like.
Vehicle scanner 20 is a device which can connect to a readout plug on a vehicle to obtain fault code information from the vehicle. For General Motors*
cars, the connector for fault code information is known as the ALDL connector. The fault code obtained by vehicle scanner 20 is supplied to computer 12, and is used to direct the testing to particular systems and components and to particular test sequences.
User I/O 22 preferably includes keyboard 22A
and display 22B. The operator/technician provides information about the particular vehicle to be tested and the tests which are desired, and responds to prompts from computer 12 which are supplied to the display 22B.
As part of the automated testing procedure, information is supplied through display 22B to the operator/technician, indicating the test conditions which must be set. For example, in some tests the vehicle's ignition must be on, while in another test the ignition must be off. Similarly, some tests require that devices be moved (such as rotating the throttle plate to see if the resistance values are in the right range). Other tests require that the engine be running.
*: Trade-Mark Display 22B, under the control of computer 12, provides the necessary prompts and setup information to the operator/technician.
In addition, display 22B provides the operator/technician with the results of the test such as the test sequence number, the value read, the tolerance required by that particular test, and good or bad indication.
External communication circuitry 24 allows computer 12 to communicate with other computers and systems. In one preferred embodiment, external communication circuitry 24 includes Controller Area Network (CAN) and RS232 communication capabilities.
Figure 2 shows control and analog processing circuitry 14, which is used to make voltage and resistance measurements and to measure pulse width. In Figure 2, vehicle ECM 30 and vehicle sensors and controls 32 are shown. Connection to ECM 30 and to vehicle sensors and controls 32 is made by breakout cable 34, which includes multipin connector 36 for connection to ECM 30, multipin connector 38 for connection to sensors and controls 32, and multipin connector 40 for connection to adaptor 42. The particular configuration of connector pins for vehicle ECM 30 and vehicle sensors and controls 32 will differ depending upon the manufacture and in some cases the model of vehicle. Breakout cable 34 is one of several different cables available to the technician, and is arranged to mate with a particular manufacturer's ECM
30 and sensors and controls 32.
Adaptor 42 provides a connection between connector 40 of breakout cable 34 and universal multipin connector 44 of circuitry 14. The operator/technician wo 9zios»' ~cTiu~~~io~~»
has available: a number of different breakout cables 34 and adaptors 42 to allow circuitry 14 to be used with a variety of d9.fferent manufacturers vehicles.
Universal connector 44 mates with adaptor 42, and provides jthe connection between the test circuits of control and analog processing circuitry 14 and the electrical system or component which is being tested.
In one preferred embodiment of the present invewtian, universal connector 44 as a 120-pin connector which has a separate ground wire 46 and allegator clamp 48 far connection to vehicle ground.
Connected to universal connector 44 is resistance m~:asuring current supply circuit 5o and voltage measuring circuit 52. Control and analog processing circuitry 14 also includes flying lead circuitry 54, aahich allows measurement between any tyro points independent of universal connector 44.
Current supply circuitry 50 includes power supply 56, pr~:cision resistors R1 and R2, relay contact 5~A and relay coil S~B, multiplexers 70 and 72 and interface 74. In a preferred embodiment of the present invention, a power supply 56 is a constant current power supply which operates at about l0 volts and supplies a 10 milliamp constant current. i~ultiplexers 70 and 72 are 64:1 multi.plexers.
The current I+ from terminal 76 of power supply 56 is :9upplied to input 70A of multiplexer 70.
Based upon a control signal from interface 74, multiplexer 70 supplies current I+ to one of its outputs, which include sixty output lines 70B which are connected to connector 44 and output line 7oC which is connected to flying lead circuitry 54. When cable 34 is being used, this causes current I+ to be steered to one Wta 92/081:13 fCr/1J591/f98317 2~"12~~~
_g_ of sixty diff~arent connection points through connector 44, adaptor 42, and cable 34. Return current I- from vehicle sensors and controls 32 is supplied through breakout cable 34 and connector 40 to adaptor 42 and then to universal connector 44. It is returned on one of sixty i~aput lines 72A to multiplexes 72.
Alternatively,, return current is returned on input line 72B from flying lead circuit 54. Interface 74 supplies a signal to n~ultiplexer 72 which selects one of the l0 input lines 72A, 72B, and routes the return current I-through output line 72C to resistor R2. rrhe return current I- flows through resistor R2 and through either resistor R1 or' relay contacts 54, depending on whether shunt relay coil 58B is energized or de-energized. The return current: I- then flows to terminal 78 of power supply 56.
Interface 74 receives signals from computer 12 and selects the particular connector to which and from which current is supplied by the resistance measuring current laop. Interface 74 also selects the range of operation by selecting whether resistor R1 will be connected in s~:rie~ with resistor R2 or will be shunted by relay contacts 58A. In one preferred embodiment of the present invention, R1 is a LOOK ohm resistor, while resistor R2 is a 200 ohm resistor.
t7olta~ge measuring circuit 52 includes electrostatic discharge (ESD) protection and scaling circuitry 80, multiplexers 82 and 84, operational amplifier 86, sample/hold and peak-to-peak detector circuit 88, autea-ranging circuitry 90, analog-to-digital (A/D) conv~ertor~ 92, pulse width tuner g4, and interface circuit g6.
ENO 9?/08141 fC1'I C1S91 /0831'7 zo l~~~o _10_ Mu:ltiplexers 82 ;and 84 are 64:1 multiplexers which receiv:~ a plurality of input lines, and provide one output line each. Sixty input lines 82A to multiplexes 82 are supplied through ESD protection and scaling circuit 80. These sixty input lines 82A are connected to the same sixty pins of connector 44 as output lines 70B of multiplexes 70. In addition, multiplexes 82 receives input line 82B, which is connected to terminal 78 of power supply 56. The VA
l0 output of flying lead circuitry 54 (which will be described in further detail later) is also supplied on input line 82C to multiplexes 82. Vehicle ground line 100 (which is connected to ground wire 46 and allegator clamp 48) is ;supplied as an input to multiplexes 82 and multiplexes 84, R3ultiplexer 84 receives sixty input lines 84A
from ESD protection and scaling circuit 80 which are connected to the same sixty pins of connector 44 as input lines 7;2A of multiplexes 72.
Multiplexes 84 also receives input line 84B
which is connected to output line 72C of multiplexes 72.
It also receives-''the VB output from flying lead circuitry 54 on input line 84C.
Mult:iplexers 82 and 84 are controlled by interface 96, which receives control signals from computer 12. :Lnterface 96 also supplies control signals which determine whether A/D convertor S2 or pulse width timer 94 sa~ill be supplying data on lines 104.
Output lines 82D and 84D of multiplexers 82 and 84 are ccannected to the inverting (-) and non investing (.+) inputs of operational amplifier 86, respectively. The output of operational amplifier 86 is supplied to both sample/hold and peak-to°peak detector WO 9?/08141 P0.°T/L1~i91/08317 circuit 88 and also to pulse width timer 94. The output of sample/holti and peak-to-peak detector circuit 88 is supplied to the auto-ranging circuitry 90 of A/D
convertor 92. When A/D convertor 92 is selected by interface 96, it converts the analog voltage which receives at its input to a 12-bit digital value which is supplied on l~.nes 104.
Pulse width timer 94, when selected by interface 96, receives the output of operational l0 amplifier 86 and times the pulse width of the signal received. The measured pulse width is supplied as digital data on lines 104 to computer 12.
Flying lead circuitry 54 includes flying lead interface 110, connector 112, and a pair of probes 114 and 116. Function generator 118 is also connected to flying lead interface 110.
Interface 74 provides a general purpose control line 1::0 which selects operation through flying lead circuit 54, rather than through breakout cable 34, adaptor 42, and universal connector 44> When selected, flying. leads probes.114 and 116 are used to contact selected leads or pins. Various voltage and resistance measurements can be made which are similar to the measurements made through sable 34. Resistance measurements current is provided to and from flying lead interface 110 through lines 70C and 72B which are connected to a~ultiplexers 70 and 72, together with voltage output lines 126 and 128 which supply the VA and VB output voltages to multiplexers 82 and 84.
3o Voltage measurements are made by circuit 14 through the use of voltage measuring circuitry 52.
Computer 12 selects, through interface 96, the two connector points of universal connector 44 which are to WO '~2/OBId 1 PC°T/~JSII /Of3317 be connected 'to A/D convertor 92. This selection is done through multiplexers 82 and 84. The output voltages from mul~tiplexers 82 and 84 are supplied on lines 82D and. 84D to operational amplifier 86, and through samplejhold and peak-to-peak detector circuitry 88 and auto-rangincy circuitry 90 to the input of AJD
convertor 92.
If additional voltages are to be measured, computer 12 c.'hanges the control signals supplied to interface 96, which causes multiplexers 82 and 84 to select other pins for connection to operational amplifier 86.
The same voltage measurements can be made through flying lead circuit 54. Interface 74 provides a control signal on line 120 to flying lead interface 110. The VA and VB voltages supplied on input lines 82C
and 84C of mult.iplexers 82 and 84, and are connected to output lines 82D and 84D and thus to the inputs of operational amplifier 86.
6dhen resistance measurements are to be made, both current supply circuit 50 and voltage measuring circuit 52 are active. Normally, breakout cable 34 will be connected only to vehicle sensors and controls 32 during a resistance measurement test. This avoids having a component within the vehicle ECM affecting the resistance measurement. During a voltage measurement, on the other hand, both ECM 30 and vehicle sensors and controls 32 are normally connected to breakout cable 34.
Power supply 5~, which is preferably a constant c~arrewt source providing current at a level of about 10 mill:iamps and nominally about ~.0 volts, supplies cLlrrent: I+ through multiplexer 70 to one of the sixty lines 70B to connector 44. The return current I°
WO 92/x8141 f('f/US91/08317 ~13-is supplied vrom connector 44 to one of the sixty input lines 721 of multiplexer 72, and then from output line 72C through one or both the resistors R1 and R2.
Computer 12 selects, through interface 74 and shunt relay coil 588, whether resistor Ftl will be shunted by contacts 58A.
When the resistance measuring made is first selected, multiplexers 82 and 84 are controlled to connect the selected two pins of connector 44 to the l0 inputs of operational amplifier 86. At this time, current is not yet being supplied through multiplexers 70 and 72, and therefore no voltage should appear between the + and ~ inputs of operational amplifier 86.
Tf a voltage does appear, the data on lines 104 to computer 12 will indicate the presence of the non~zero voltage, and <:amputer 12 will stop and provide a message through display 22B. Computer 12 will not allow a resistance measurement to continue until the operator/technician supplies an input through keyboard 22A indicating that the condition has been corrected.
Typically, this situation will occur because 8~ 30 has nat been disconnected from breakout cable 34.
Tf no voltage appeared on the selected pins, computer 12 will instruct multiplexers 70 and 72 to select the ;game two pins which are selected by multiplexers 82 and 84. Circuitry 14 is then ready to perform the raseietxncs check.
~iultiplexers 82 and 84 are instructed to set measuring points to lines 82B and 848. The voltage reading between these two lines represents the voltage across resistors R1 and R2. Since the resistance between ii.nes 828 and 84B is knawn (i.e., either R1 + R2 or just ~t2), the voltage reading which is obtained WO 9?/08141 P(:T/iJS91/08~1'7 _14_ provides an ;indication of the current which is flowing through the current loop.
Co~uputep 12 then instruct, a~ultiplexers 82 and 84 to read ~:he voltage across the pre-selected pins.
Since the current was known by the previous measurement, computer 12 is able to derive the resistance by measuring the: voltage between the two pins and dividing that voltage by the current which had just been read.
This method allows the reading of very small resistances very accurately. The internal resistances of multiplex~:rs 70, 72, 82 and 84 do not affect the accuracy of the measurement. As a result, the present invention allows the use of solid state multiplexers which are substantially lower cost, more reliable, and more compact than relays.
Figure 3 shows a simplified version of the resistance measurement circuitry shown in Figure 2. In Figure 3, digital voltmeter 150 represents the circuitry formed by operational amplifier 86, sample/hold and peak-to-peak detector circuitry 88, auto~ranging circuitry 90, and A/D convertor 92. Tn addition, the diagram is simplified by not showing ljreakout cable 3~, adaptor 42, universal connector 4~ and flying lead circuitry 54. The resistance to be measured is referred to R~r the voltage across resistors E1 and R1 is Eg, and the voltage across resistor Rx is Ex.
)luring the first measurement, the voltage Eg is read by digital voltmeter 150 through multiplexers 82 and 84. The current I~ is:
WO 92/08141 1'CT/11591/t18317 Es '~X~ ~z+R2 Eq. 1 In the next step of the process, digital voltmeter 150 reads voltage Ex. Since Ix is already known and Ex is measured, resistance Rx can be determined by:
E
Rx~ l.x Eq . 2 x The internal resistances of multiplexers 70 and 72 are not involved in these readings. Ee is measured dires:tly across resistors Rl and R2, and Ex is measured directly across Rx. Multiplexers 70 and 72 simply steer the current Ix to and from resistor Rte, but are not involved in the voltage measurements from which resistance R~ is derived.
The internal resistances of multiplexers 82 and 84 also do not affect the voltage readings because those resirtances (approximately 75 ohms) are very small compared to the high input impedance (typically 10 megohans) of digital voltmeter 150.
The resistance measuring technique of the present invention offers another unique capability for breakout box :10. It is possible, with the present invention, to measure cross-talk between various lines and sensors. This can be done by supplying current '~O 92/08141 PCT/U591/0$~17 2D ~~~~0 ms~
through multpiplexers 70 and 72 to one set of pins, and then measuring voltages through multiplexers 82 and 84 on different sets of pins.
~.lt:hough the present invention has been described with reference to preferred embodiments, workers skil7.ed in the art will recognize that changes may be made an form and detail without departing from the spirit and scope of the invention.
Claims (26)
- WHAT IS CLAIMED IS:
~ A resistance measurement system for measuring resistances between a plurality of points, the system comprising:
a power supply;
resistance means connected in a series circuit with the power supply;
first solid state multiplexer means having an indefinite internal resistance which varies with temperature, for connecting the series circuit to a selected pair of the points;
a voltmeter;
second solid state multiplexer means having an indefinite internal resistance which varies with temperature, for selectively connecting the voltmeter to measure a first voltage across the resistance means and a second voltage between the selected pair of points; and means for deriving a resistance value based upon the measured first and second voltages. - 2. The system of claim 1 and further comprising:
a breakout cable for connection to a multiconductor connector of an automotive vehicle, the breakout cable being connected to the first and second multiplexer means. - 3. The system of claim 1 wherein the voltmeter is a digital voltmeter which provides digital data representative of the first and second voltages, and wherein the means for deriving a resistance includes a digital computer.
- 4. The system of claim 3 and further comprising:
user input means for providing input signals to the computer; and display means connected to the computer for displaying results of measurements. - 5. The system of claim 3 wherein the computer provides control signals to the first and second multiplexer means.
- 6. An apparatus for performing a test sequence on a plurality of electrical components of a vehicle of a type having an electronic control module (ECM), the apparatus comprising:
means for retrieving the test sequence;
a microcontroller for executing the test sequence;
means for selectively isolating the ECM from the plurality of electrical components and providing access to electrical connections leading to the plurality of electrical components;
a current supply comprising:
a power supply;
resistance means having a known resistance; and first multiplexer means responsive to the microcontroller, for selectively routing a current from the power supply through the resistance means and a pair of electrical connections wich lead to a selected electrical component of the plurality of electrical components;
a voltage measuring circuit comprising:
means for sensing a voltage and providing an output representative of the voltage to the microcontroller; and second multiplexer means responsive to the microcontroller, for selectively connecting the means for sensing a voltage to sense a first voltage across the resistance means and a second voltage across the pair of electrical connections;
means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
means for determining a condition of the selected electrical component based upon the second voltage and the magnitude of the current; and means for providing an output representative of the condition of the selected electrical component. - 7. The apparatus of claim 6 wherein the means for retrieving a test sequence includes:
user input means for providing input to the microcontroller; and data storage means for storing the test sequence. - 8. The apparatus of claim 6 wherein the means for selectively isolating the ECM comprises a breakout cable, the breakout cable comprising:
first multipin connector means connectable to the ECM, second multipin connector means connectable to the plurality of electrical components, wherein a plurality of conductors couple the first and second multipin connector means; and third multipin connector means for coupling the plurality of conductors to the first and second multiplexes means. - 9. The apparatus of claim 6 wherein the resistance means is comprised of:
first and second resistors connected in series; and shunting means connected in parallel with the first resistor and responsive to the microcontroller, for providing the resistance means with a resistance equal to a resistance of the second resistor, or alternatively, a sum of the resistance of the first resistor and a resistance of the second resistor. - 10. The apparatus of claim 6 wherein the first multiplexes means comprises first and second solid state multiplexers, and wherein the second multiplexer means comprises third and fourth solid state multiplexers.
- 11. The apparatus of claim 6 wherein the means for providing an output comprises a video display.
- 12. An automotive vehicle test apparatus for testing an electrical system of an automotive vehicle, the electrical system including an electronic control module connected to a plurality of electrical components by a plurality of conductors which form an electronic control module bus for carrying electronic signals between the electronic control module and the plurality of electrical component, the test apparatus comprising:
a multipin connector adapted for connecting to the electranic control module bus whereby access to the plurality of conductors is provided to the test apparatus;
a first multiplexer coupled to the multipin connector for selectively providing a current path between a pair of conductors of the electronic control bus;
a second multiplexer coupled to the multipin connector and having a pair of outputs selectively connected across a pair of conductors of the electronic control bus;
means for sensing voltage across the outputs of the second multiplexer and providing a representative digital output; and controller means for instructing the first multiplexer to provide a current path between a pair of conductors of the electronic control bus, instructing the second multiplexer to connect the pair of outputs to a pair of conductors of the electronic control bus, receiving the digital output from the means for sensing voltage, performing a test based upon the digital output and providing an output based upon results of the test. - 13. A method for performing a test sequence on a plurality of electrical components in a vehicle of a type having an electronic control module, the method comprising;
retrieving the test sequence;
isolating the electronic control module from the plurality of electrical components;
routing a current through a known resistance and a selected component of the plurality of components;
sensing a first voltage across the known resistance and a second voltage across the selected component;
determining a magnitude of the current based upon the first voltage and the known resistance;
determining a condition of the selected component based upon the second voltage and the magnitude of the current; and providing an output representative of the condition of the selected electrical component. - 14. A method for performing a test sequence on a plurality of electrical components in a vehicle of a type having an electronic control module, the method comprising;
retrieving the test sequence;
isolating the electronic control module from the plurality of electrical components;
providing access to a plurality of electrical connections which lead to the electrical components;
routing a current through a known resistance and a first set of electrical connections of the plurality of electrical connections;
sensing a voltage across a second set of electrical connections of the plurality of electrical connections;
deriving a quantity representative of cross-talk based upon the first and second sets and the sensed voltage; and providing an output representative of cross-talk. - 15. The method of claim 14 wherein the first set comprises first and second conductors, and wherein the second set comprises third and fourth conductors.
- 16. The method of claim 14 wherein the first set comprises first and second conductors, and wherein the second set comprises the second conductor and a third conductor.
- 17. An apparatus for performing a test sequence on a plurality of electrical components of a vehicle of a type having an electronic control module (ECM), the apparatus comprising:
means for retrieving the test sequence;
a microcontroller for executing the test sequence;
means for selectively isolating the ECM from the plurality of electrical connections leading to the plurality of electrical components;
a current supply comprising:
a power supply;
resistance means having a known resistance; and first multiplexer means responsive to the microcontroller, for selectively routing a current from the power supply through the resistance means and a pair of electrical connections which lead to a selected electrical component of the plurality of electrical components;
a voltage measuring circuit comprising:
means for sensing a voltage and providing an output representative of the voltage to the microcontroller; and second multiplexer means responsive to the microcontroller, for selectively connecting the means for sensing a voltage to sense a first voltage across the resistance means and a second voltage across the pair of electrical connections;
means for determining a magnitude of the current based upon the first voltage and the known resistance of the resistance means;
means for determining a condition of the selected electrical component based upon the second voltage and the magnitude of the current; and means for providing an output representative of the condition of the selected electrical component. - 18. The apparatus of claim 17 wherein the means for retrieving a test sequence includes:
user input means for providing input to the microcontroller; and data storage means for storing the test sequence. - 19. The apparatus of claim 17 wherein the means for selectively isolating the ECM comprises a breakout cable, the breakout cable comprising:
first multipin connector means connectable to the ECM, second multipin connector means connectable to the plurality of electrical components, wherein a plurality of conductors couple the first and second multipin connector means; and third multipin connector means for coupling the plurality of conductors to the first and second multiplexer means. - 20. The apparatus of claim 17 wherein the resistance means is comprised of:
first and second resistors connected in series;
and shunting means connected in parallel with the first resistor and responsive to the microcontroller, for providing the resistance means with a resistance equal to a resistance of the second resistor, or alternatively, a sum of the resistance of the first resistor and a resistance of the second resistor. - 21. The apparatus of claim 17 wherein the first multiplexer means comprises first and second solid state multiplexers, and wherein the second multiplexer means comprises third and fourth solid state multiplexers.
- 22. The apparatus of claim 17 wherein the means for providing an output comprises a video display.
- 23. A method for performing a test sequence on a plurality of electrical components in a vehicle of a type having an electronic control module, the method comprising;
retrieving the test sequence;
isolating the electronic control module from the plurality of electrical components;
providing a first select signal to a first multiplexer to route a current through a known resistance and a selected component of the plurality of components;
providing a second select signal to a second multiplexer to sense a first voltage across the known resistance;
providing a third select signal to the second multiplexer to sense a second voltage across the selected component;
determining a magnitude of the current based upon the first voltage and the known resistance;
determining a condition of the selected component based upon the second voltage and the magnitude of the current; and providing an output representative of the condition of the selected electrical component. - 24. A method for performing a test sequence on a plurality of electrical components in a vehicle of a type having an electronic control module, the method comprising;
retrieving the test sequence;
isolating the electronic control module from the plurality of electrical components;
providing access to a plurality of electrical connections which lead to the electrical components;
controlling a first multiplexer to route a current through a known resistance and a first set of electrical connections of the plurality of electrical connections;
controlling a second multiplexer to sense a voltage across a second set of electrical connections of the plurality of electrical connections;
deriving a quantity representative of cross-talk based upon the first and second sets and the sensed voltage; and providing an output representative of cross-talk. - 25, The method of claim 24 wherein the first set comprises first and second conductors, and wherein the second set comprises third and fourth conductors.
- 26. The method of claim 24 wherein the first set comprises first and second conductors, and wherein the second set comprises the second conductor and a third conductor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/610,213 US5177447A (en) | 1990-11-06 | 1990-11-06 | Automated breakout box for automotive testing |
| US610,213 | 1990-11-06 | ||
| PCT/US1991/008317 WO1992008141A1 (en) | 1990-11-06 | 1991-11-06 | Automated breakout box for automotive testing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2072980A1 CA2072980A1 (en) | 1992-05-07 |
| CA2072980C true CA2072980C (en) | 2001-07-03 |
Family
ID=24444138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002072980A Expired - Fee Related CA2072980C (en) | 1990-11-06 | 1991-11-06 | Automated breakout box for automotive testing |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5177447A (en) |
| EP (1) | EP0509091A4 (en) |
| JP (1) | JP3271144B2 (en) |
| AU (1) | AU9082991A (en) |
| CA (1) | CA2072980C (en) |
| WO (1) | WO1992008141A1 (en) |
Families Citing this family (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9016533D0 (en) * | 1990-07-27 | 1990-09-12 | Churchill V L Ltd | Automotive diagnostic tool |
| US5315252A (en) * | 1992-08-26 | 1994-05-24 | Spx Corporation | Automotive test system with input protection |
| US6240345B1 (en) * | 1993-04-15 | 2001-05-29 | Alliedsignal Inc. | Integrity monitor for TCAS mutual suppression |
| US5640093A (en) * | 1994-05-23 | 1997-06-17 | Cardone Industries, Inc. | Automobile electronic circuit analyzer for detecting shorted ECM loads, including a pulsating power supply and load sensing cell |
| DE4443350C1 (en) * | 1994-12-06 | 1996-04-04 | Hella Kg Hueck & Co | Control and monitoring circuit for automobile electrical loads |
| US5574645A (en) * | 1995-02-28 | 1996-11-12 | Snap-On Technologies, Inc. | Manifold absolute pressure sensor emulator |
| US5748008A (en) * | 1995-12-06 | 1998-05-05 | Landreth; Keith W. | Electrical integrity test system for boats |
| DE19546553C1 (en) * | 1995-12-13 | 1997-05-07 | Daimler Benz Ag | Method for testing electrical consumers in a vehicle electrical system |
| US5686840A (en) * | 1996-05-08 | 1997-11-11 | Automotive Controls Corporation | Method and apparatus for throttle position sensor testing |
| JP3052843B2 (en) * | 1996-07-03 | 2000-06-19 | 住友電装株式会社 | Electrical junction box |
| KR20010014055A (en) | 1997-06-25 | 2001-02-26 | 스넵-온 툴스 캄파니 | Electrical tester for small motor vehicles |
| US5937368A (en) * | 1997-06-30 | 1999-08-10 | Chrysler Corporation | User-definable electrical test query for vehicle quality assurance testing during manufacture |
| US6104988A (en) * | 1998-08-27 | 2000-08-15 | Automotive Electronics, Inc. | Electronic control assembly testing system |
| JP3426152B2 (en) * | 1999-02-16 | 2003-07-14 | 株式会社オートネットワーク技術研究所 | Inspection method for in-vehicle electronic unit |
| US7811606B2 (en) * | 2003-04-16 | 2010-10-12 | Dey, L.P. | Nasal pharmaceutical formulations and methods of using the same |
| DE102006008539A1 (en) * | 2006-02-22 | 2007-08-30 | Robert Bosch Gmbh | Error condition simulating method for use in control device, involves connecting circuit points of device to be tested with points of fault generation circuit across multiplexer, and multiplexer is implemented using relay technology |
| US7664579B2 (en) * | 2006-03-27 | 2010-02-16 | Eddie Sirhan | Test interface for diagnosing communication faults in automobiles |
| US20090118893A1 (en) * | 2007-11-05 | 2009-05-07 | Xiuyu Che | Method of integrated detection for automobile instruments |
| GB2466001A (en) * | 2008-12-05 | 2010-06-09 | Gm Global Tech Operations Inc | Breakout system and breakout box for measuring signals between an on-board system under test and an electronic control unit in a vehicle |
| KR101211886B1 (en) * | 2010-11-29 | 2012-12-13 | 주식회사 현대케피코 | Multi Break-out Box |
| DE102012220738A1 (en) * | 2012-11-14 | 2014-05-15 | Robert Bosch Gmbh | Measuring circuit for determining resistance value of sensor resistor element for motor vehicle control device, has power supply terminal, which is electrically connected with pole of supply voltage source |
| KR101385282B1 (en) | 2012-12-26 | 2014-04-17 | (주)뉴튼스포스코리아 | Breakout box for power analyzer |
| DE102014203483A1 (en) | 2014-02-26 | 2015-08-27 | Robert Bosch Gmbh | Isolation adapter, adapter cable and diagnostic system for a vehicle |
| US9753073B2 (en) | 2015-11-23 | 2017-09-05 | General Electric Company | Method and systems for testing an electrical circuit |
| US10126328B1 (en) | 2016-11-15 | 2018-11-13 | The United States Of America As Represented By The Secretary Of The Navy | Electrical measurement test fixture |
| KR101863601B1 (en) | 2016-11-17 | 2018-07-05 | 한국항공우주연구원 | Organization of Breakout Box for Verifying Signal of Artificial Satellite |
| DE102016225225A1 (en) * | 2016-12-16 | 2018-06-21 | Robert Bosch Gmbh | Apparatus and method for driving a solenoid valve |
| WO2018196986A1 (en) * | 2017-04-27 | 2018-11-01 | Advantest Corporation | Calibration arrangement and method for deriving a resistance of a resistor |
| EP3729576A4 (en) * | 2018-11-02 | 2020-12-02 | Meditech Mühendislik Medikal Sanayi Ve Ticaret Ltd Sti | Automatic multi-channel electronic test and measurement device |
| US11519945B2 (en) * | 2019-12-20 | 2022-12-06 | The United States of America as represented by the Federal Bureau of Investigation, Department of Justice | Circuit test device and method |
| US11460374B1 (en) | 2020-11-11 | 2022-10-04 | David M. Cope | Engine testing mechanism |
| GB2612357A (en) * | 2021-10-29 | 2023-05-03 | Aptiv Tech Ltd | Testing device, method, and software for testing an automotive controller |
| EP4290249A1 (en) * | 2022-06-08 | 2023-12-13 | Thorsten Schneider | Diagnostics for electrical car |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2710375A (en) * | 1950-05-20 | 1955-06-07 | Battelle Development Corp | Resistor testing device |
| US4757463A (en) * | 1986-06-02 | 1988-07-12 | International Business Machines Corp. | Fault isolation for vehicle using a multifunction test probe |
| FR2617597B1 (en) * | 1987-06-30 | 1989-10-13 | Peugeot | DEVICE AND ASSEMBLY FOR TESTING AND ASSISTING THE DIAGNOSIS OF A FUNCTION CARRIED OUT BY AN ON-BOARD ELECTRONIC SYSTEM ON A MOTOR VEHICLE AND ITS IMPLEMENTING METHOD |
| ATE85133T1 (en) * | 1989-02-16 | 1993-02-15 | Mania Gmbh | CIRCUIT FOR MEASURING RESISTANCES OF TEST PIECES. |
-
1990
- 1990-11-06 US US07/610,213 patent/US5177447A/en not_active Expired - Lifetime
-
1991
- 1991-11-06 CA CA002072980A patent/CA2072980C/en not_active Expired - Fee Related
- 1991-11-06 WO PCT/US1991/008317 patent/WO1992008141A1/en not_active Application Discontinuation
- 1991-11-06 JP JP50189692A patent/JP3271144B2/en not_active Expired - Fee Related
- 1991-11-06 EP EP19920900939 patent/EP0509091A4/en not_active Ceased
- 1991-11-06 AU AU90829/91A patent/AU9082991A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JP3271144B2 (en) | 2002-04-02 |
| EP0509091A1 (en) | 1992-10-21 |
| US5177447A (en) | 1993-01-05 |
| JPH05503583A (en) | 1993-06-10 |
| CA2072980A1 (en) | 1992-05-07 |
| EP0509091A4 (en) | 1993-02-24 |
| WO1992008141A1 (en) | 1992-05-14 |
| AU9082991A (en) | 1992-05-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2072980C (en) | Automated breakout box for automotive testing | |
| CA1143794A (en) | Apparatus and method for testing and controlling manufacture of a vehicle electrical system | |
| US4207611A (en) | Apparatus and method for calibrated testing of a vehicle electrical system | |
| US5532927A (en) | Automotive diagnostic tool | |
| US5172062A (en) | Device for testing electrical appliances used in a motor vehicle | |
| US6771073B2 (en) | Microprocessor-based hand-held electrical-testing system and method | |
| US6933727B2 (en) | Electronic battery tester cable | |
| US6707303B2 (en) | Electronic battery tester | |
| US5315252A (en) | Automotive test system with input protection | |
| EP0225904B1 (en) | Improvements in or relating to apparatuses for testing cables | |
| US5325068A (en) | Test system for measurements of insulation resistance | |
| GB2354335A (en) | Automotive testing | |
| US20050052186A1 (en) | Circuit testing device for testing electrical subsystems of vehicles | |
| CN111913136A (en) | Method for detecting whether test bit and tester interface are connected in error or not and chip test system | |
| CN116449277A (en) | Detection and calibration system for ATE test equipment and control method thereof | |
| JPH07159474A (en) | Device for diagnosing electrical wiring of vehicle | |
| JPH0115828B2 (en) | ||
| KR20210079092A (en) | Apparatus for steering wheel multi test with pin mapping | |
| KR20010018451A (en) | method for testing a wire harness and system for performming the same | |
| EP0873522A1 (en) | Apparatus and method for electrical system measurement | |
| CN114113748B (en) | Charging detection device | |
| KR100396846B1 (en) | Method for finding connection troubles by measuring relative voltage between two points using multichannel scanner in examining defect of vehicle | |
| JPH08320350A (en) | Relay characteristic automatic testing device | |
| CN117147988A (en) | Tester, test system and method for testing electrical components | |
| KR20000070061A (en) | Ic testing method and ic testing device using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |