CA1158310A - Test system for a dynamic machine - Google Patents
Test system for a dynamic machineInfo
- Publication number
- CA1158310A CA1158310A CA000341813A CA341813A CA1158310A CA 1158310 A CA1158310 A CA 1158310A CA 000341813 A CA000341813 A CA 000341813A CA 341813 A CA341813 A CA 341813A CA 1158310 A CA1158310 A CA 1158310A
- Authority
- CA
- Canada
- Prior art keywords
- machine
- block
- test system
- shutdown
- control
- 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
Links
- 238000012360 testing method Methods 0.000 title claims abstract description 57
- 230000009993 protective function Effects 0.000 claims abstract description 11
- 238000012544 monitoring process Methods 0.000 claims abstract 4
- 230000006870 function Effects 0.000 claims description 14
- 230000004936 stimulating effect Effects 0.000 claims description 8
- 230000000007 visual effect Effects 0.000 claims description 4
- 239000000446 fuel Substances 0.000 description 23
- 238000000034 method Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 239000003921 oil Substances 0.000 description 8
- 239000010725 compressor oil Substances 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- 208000024891 symptom Diseases 0.000 description 2
- 241001125929 Trisopterus luscus Species 0.000 description 1
- 230000009118 appropriate response Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000007619 statistical method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M15/00—Testing of engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Testing Or Calibration Of Command Recording Devices (AREA)
- Control Of Eletrric Generators (AREA)
- Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
- Testing Of Engines (AREA)
Abstract
TEST SYSTEM FOR A DYNAMIC MACHINE
Abstract of the Disclosure A control and test system for a dynamic machine utilizing condition sensors to gather information concerning machine operation. A programmed processor analyzes the information and provides control signals to actuate elements which operate the machine. The programmed processor monitors the machine operation with protective functions and shuts the machine down in the event of a serious fault. The cause of a shutdown is recorded in a nonvolatile memory.
The test system has a passive mode during operation of the machine monitoring inputs from sensors and the machine operation. Intermittent and continuous faults which do not cause machine shutdown are recorded in the memory. An active test mode is performed when the machine is shut down, checking sensor circuits, machine control elements and the control and protection processor programs. Faults are recorded in the memory. The cause of a machine shutdown and other faults stored in the memory are retrieved and displayed for a serviceman.
Abstract of the Disclosure A control and test system for a dynamic machine utilizing condition sensors to gather information concerning machine operation. A programmed processor analyzes the information and provides control signals to actuate elements which operate the machine. The programmed processor monitors the machine operation with protective functions and shuts the machine down in the event of a serious fault. The cause of a shutdown is recorded in a nonvolatile memory.
The test system has a passive mode during operation of the machine monitoring inputs from sensors and the machine operation. Intermittent and continuous faults which do not cause machine shutdown are recorded in the memory. An active test mode is performed when the machine is shut down, checking sensor circuits, machine control elements and the control and protection processor programs. Faults are recorded in the memory. The cause of a machine shutdown and other faults stored in the memory are retrieved and displayed for a serviceman.
Description
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TEST SYSTEM FOR A DYNAMIC MACHINE
Specification This invention is concerned with a test system or a dynamic machine or the like in which fault conditions are recognized and recorded to aid in servicing.
The invention is illustrated with an auxiliary power unit tAPU~ for an aircraEt, and some of the features o the system disclosed are particularly suited therefor. Other features of the invention are of more general application and can be used in the protection and testing of other dynamic machines.
A general discussion of the construction and operation of an APU will aid in appreciation of the problems of the prior art and an understanding of the significance of the invention. A typical APU includes an engine which drives a generator and a compressor to provide electrical power for selected loads and compressed air for environmental and other purposes, when the aircraft is on the ground. The APU
is also operated in an emergency when the aircraft is airborne to supplement or replace faulty equipment. The APU
en~ine uses jet fuel which is burned to form a gas that operates a turbine to drive the generator and the compressor. Various conditions of the APU are sensed to provide inputs to a controller which controls the fuel to the APU, other Eunctions related to the APU and which shuts the APU down in the event of a malfunction.
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Prior APU test systems have monitored sensed APU
conditions. Upon the occurrence of a condition which is out of tolerance, an indication of a unit failure is given, based on a statistical analysis of probable cause. This is unsatisfactory in practice as the inclicated probable cause is at best an educated guess. Furthermore, the statistical failure analysis made during development of a dynamic machine is not accurate for a mature system. Service personnel have learned that the test system fault indications are unreliable and often ignore them.
A principal feature of the invention is the provision of a test system which monitors individual components of a dynamic machine and identifies faults. When a fault occurs that causes a shutdown, the test system determines the shutdown cause. The test system includes a memory in which the identity of the faulty element is stored. A visual display is connected with the memory and displays the stored fault information.
One feature of the invention is the prov:ision of a ~0 passive test system which monitors outputs of the machine condition sensors and various controller parameters.
Another feature is the provision of an active test system which checks sensors and actuating elements that cannot be checked when the machine is operating, stimulates control outputs and checks the actuating elements and which supplies inputs to the machine control and checks Eor appropriate responses.
A further feature of the invention is that fault information including information regarding the cause of plural successive shutdowns is stored in a me~ory and available through a visual display.
Further features and advantages of the invention will readily be apparent from the following specification and Erom the drawings, in which:
~ ~5~310 Figure 1 is a diagrammatic perspective illustration ~f an aircraft auxiliary power unit Figure 2 is a general block diagram of the APU control and protection circuits;
Figure 3 is a detailed block diagram of the APU with condition sensors and actuator elements relevant to an understanding of the invention;
Figures 4 and 5 are flow charts for the passive an~
active test systems, respectively;
Figure 6 is a flow chart for the protective functions;
Figure 7 is a flow chart for the operation of the protective functions;
Figure 8 is a flow chart for the initialization procedure, Figure 9 is a flow chart for the status procedure;
Figures 10, 11 and 12 are flow charts Eor the processor on occurrence of a fault;
Figure 13 is a flow chart for the shutdown procedure;
Figure 14 is a flow chart illustrating storage of fault information in the memory, Figure 15 is a flow chart of the passive test system;
Figure 16 is a flow chart of the active test system display routine;
Figure 17 is a flow chart for the check of protective functions which is a part of the active test system;
Figure 18 is a flow diagram for the check of control functions which is a part of the active test system;
Figure 19 is a flow chart for the isolation of a deLective unit which is a part of the active test system;
Figure 20 is a flow chart for the procedure of clearing of the memory;
Figure 21 is a block diagram of a circuit for stimulating an output of the machine control;
Figure 22 is a block diayram illustrating the application of an AC stimulating signal to an input of the machine control; and ~ ~583~) Fi~ure 23 is a ~lock dia~ram illustrating the appli~
cation of a DC stimulating signal to an input of the machine control.
The auxiliary power unit - APU - of Figure 1 and 2 is an illustration of a controlled dynamic machine with which the test system of the invention is particularly use~ul. Glennon U.S. Patent No. ~,118,688, October 3, 1978, shows a prior test system used with an aircra-Et electrical generator driven by a constant speed drive, an illustration of another controlled dynamic machine with which the inven*ion is useful. There are other dynamic machines or apparatus of greater or lesser com-plexity for which the passive and active tes-t systems and ~ault recording is useful.
The term "dynamic machine", or "controlled dynamic machine", is used herein to designate an appara-tus which has active func*ions, as star~ing, operating and stopping, as direct-ed by actuator elements. Sensors or operator controls, or a combination thereof, provide in~ormation to a machine control which in turn generates control signals that are direc-ted to the actuator elements. The nature of the opera-tion of the machine is often estahlished in accordance with a predetermined function or program based on the input in~ormation from the sensors or from an operator.
The auxiliary power unit 30 illustrated diagram~atically in Figure 1 is powered by a -turbine engine 31 which uses air-craft jet fuel. The fuel is delivered from an aircraft fuel system through line 32 and fuel pump 35 to fuel metering valve 33 which controls *he fuel flow to the APU. A solenoid operat-ed valve 34 affords an on-off control of the APU. Fuel is delivered from pump 35 to a ~as chamber 37 in which the fuel is .~
1 mixed with air from engine compressor 38 and burned to generate gas which drives the turbine 31. The AP~ is started ~y a battery powered motor (not shown) which drives the engine compressor 38. At the appropriate speed, fuel valve 34 and metering valve 33 are opened delivering fuel to the gas producer where it is ignited.
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The turbine shaft 40 is connected throu~h gearing indicated generally at 41 to drive an air compressor 42 and a three-phase electrical generator 43. ~ir inlet duc~s 45, 46 and 47 direct air to the gas generator compressor, compressor 38, compressor 42 and to a cooling fan 48 which circulates air through the APU compartment of the aircraft.
Air from compressor 42 is utilized in the a.ircraEt environmental system, e.g., to circulate fresh air through the cabin, for main engine starting and for powering an emergency hydraulic pump. Other apparatus capable of being operated by compressed air may also be connected with the compressor.
Generator 43 provides electrical power to loads, as lights, controls, communication equipment and the :Like when the aircraft is on the ground. The APU may be ope:rated when the aircraft is airborne and the generator 43 may be connected to supplement the e:Lectrical supply, as when one of the main generators is inoperative.
The APU controller 50 illustrated in bloelc form in Figures 2 and 3 is preferably a programmed microprocessor which responds to inputs from sensors in the APU and from the aircraft, providing outputs to APU actuator elements and to operation displays in the aireraftO The control.ler 50 is divided into two portions, a control processor 52 and a protection processor 53. The control processor is in charge of the start-up and operation of the APU. The protection processor detects faults, orders ~PU shutdown and tests the system.
The protection processor 53 is eonnected through a multiplexer 54 with the APU sensors and actuator elements and the control processor inputs to conduct tests, as will appear. When a fault is detected, the identlty of that fault is communicated from the protection processor 53 to a fault indicating memory 55. The serviceman can call up the recorded fault information on a v.isual fault display 56.
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The APU and aircraft interconnection with the controller is shown in more detail in Figure 3. APU sensor inputs to the controller 50 include:
61 - incoming fuel temperature T~
62 - gas producer compressor, dis-charge pressure CDP
63, 63'- gas producer speed sensors NG
#1, ~2 (two speed sensors are used for added reliability) 64 - measured gas temperature - MGT -in the gas producer 65, 65l_ power turbine speed sensors Npt #1 and #2 67 - differential pressure QP in lS the load compressor 42 68 - inlet pressure PIN for the load compressor 69 - output pressure PoUT for the load compressor 70 - low oil pressure - LOP - in the load compressor 71 - high oil temperature - HOT -in the load compressor 72 - low oil quantity - LO~ - in the load compressor.
Outputs Erom the electronic controller 50 are connected with the following APU actuator elements:
~5 - rotary actuator for fuel meter-ing valve 33 sets the fuel flow to the APU. A valve position feedback 75 provides an input to electronic controller 50 com-pleting a servo loop for the fuel valve 1~5~3~
76 start contactor provides elec-trical power to the start motor (not shown) 77 - igniter ignites the fuel in the gas producer 78 - surge valve actuator opens a by-pass valve~on the load compres~
-~ sor 42 to minimize a surge con-dition. Valve position feedback 8~ c c~7~ ~c7~c s ;~ lcti~ a servo loop with actuator 78 for the surge valve 81 - inlet guide vane actuator for the inlet guide vanes of the load compressor. Inlet guide vane position feedback 82 com-pletes a servo loop for the in-let guide vane actuator.
Additional inputs to electronic controller 50 include:
85 - ambient temperature~ ~amb 86 - Start/On command from the air-craft 87 - AIR/GROUND signal from the air-craft 88 - a signal indicating the status of the main aircraft electrical generating system 89 - main engine start signal.
Other outputs of electronic controller 50 include the following display signals to the aircraft:
92 - load compressor unload 93 - APU fault 94 - APU shutdown 831~
95 - APU ready to load 9G - gas temperature for a meter display.
The invention is concerned wi~h the test system and its relation to the protection processor 53. Accordingly, the programming of control processor 52 will not be considered in detail. It is sufficient to understand that upon initiation of the APU operation the start motor is energized to drive engine compressor 38, the igniter is turned on and fuel valve 34 opened. These operations are controlled sequentially primarily on the basis o gas producer speed NG and time delays. For shutdown, the fuel valves are closed.
The opera-tion of the passive and active test systems will be described, primarily with reference to the program flow diagrams, Figures 4-20, which represent the protection and test programs performed by protection processor 53.
A principal feature of the invention is the provision of passive and active test systems with a memory which records faulty components and the causes of shutdown before subsequent display. The operation of these test systems is illustrated diagrammatically in Figures 4 and 5.
The passive test, Figure 4, functions con-tinually during operation of the auxiliary power unit. At block 100 passive identification of nonshutdown faults is conducted.
Any faults that are noted are stored at block 101 in the nonvolatile memory 55. In the event o~ a shutdown, the passive system identifies the cause at block 102. IE a shutdown is indicated at block 103, the pertinent symptoms are identified at block 104 and recorded in the memory 55 at block 105. If shutdown is not indicated, the program returns ~rom block 103 to block 100 and continues.
The active test is manually initiated following an APU
shutdown as indicated at block 107, Figure 5. At block 108 controller 50, its various inputs, the APU sensors and the 3 ~ ~
~9 APU actuating element, all shown in ~igure 3, are checked.
At block lOg a determination is made whether the controller is functioning properly. If it is, a check is made at block 110 of the aircraft inputs and APU sensor signals. The results of this check and of previous shutdown causes is displayed at 111. If a unit of the APU which is replaceable on the flight line (LRU) can be isolated, this inEormation is displayed at block 112. If the controller is determined to be inoperative, block 109, this information and the causes oE previous shu~downs are displayed at bloclc 113/
followed by a display that the controller has failed, bloclc 114.
The overall protective function flow chart is shown in Figure 6. Following power up and initialization of the APU
at block 118, fault checks are made at block 119 and operation of the passive test system commences at block 120. The active test sytem is checked and the memory cleared at block 121.
Figure 7 shows in more detail the steps included in the protective functions. Following power up block 124 and initialization of the system block 125 (see Figure 8 below~, a determination is made at block 126 whether the gas producer speed NG is below or above 8% oE operating speed. If the speed is less than 8~, the system status i5 checked at block 127 (see Figure 9 below). IE the gas producer speed is greater than 8%, the passive test system, block 128, is made operative.
The initialization procedure, Figure ~ precedes the startup of operation of the APU~ All system outputs are disabled at bloclc 130. Then all data and program flags are reset at block 131. The watchdog timer WDT Eor the controller is tested at 132 and a determination is made whether it is operating properly at bloek 133. WDT cycles periodically. If a system failure prevents its operation~
3S the APU is shut down, block 134. If the watchdog timer operates properly, the controller counters are reset or ~1~83~
initialized at 135. The Erequency to digital F/D signal converters which operate with the speed sensors 63, 63' and 65, 65l are started at block 136. The system clock is started at block 137 and the system interrupts are enabled at block 138. This completes the initialization procedures.
~ he system status program, block 127, Figure 7, is illustrated in Figure 9. After determining the status of manual switches at block 142, the BITE button is checked at block 143, and if it has been actuated the active ~est system is initiated at block 144, see Figure 16. If the ~ITE button is not actuated, the clear button is checked and if it is actuated the memory is cleared at block 146, see Figure 20. If there has been a momentary loss of DC power r the check at block 147 will shut the ~PU down, block 148.
The system can be restarted only after manual actuation of the ON/OFF switch.
Figures 10, 11 and 12 illustrate the tests perEormed to detect the occurrence of a fault. In Figure 10, at block ~so the analog/~ controller inputs are checked. These include, for exampleJ temperature and pressure sensors in the APU. At block 151 the status of input is checked. At block 152, control functons of the control processor 52 are obtained through the handshake connection, Figure 2c At block 153 checks are made of the speed Erom the various APU
speed sensors. At block 154 a fire condition is checked;
and at block 155 the position of the inlet door ls examined. At block 156 the engine compressor discharge pressure is checked. Block 157 examines the load compressor oil pressure while block 158 checks the load compressor oil temperature. In each oE blocks 154-158, if a Eault condition is detected, the APU is shut down at block 160.
The ambient temperature is checked at 161. IE the reading is not reasonable, a fault identiEication is stored at block 162, see Figure 14. Similarly, fuel temperature Tf is checked at block 163. Blocks 164, 165, the outputs of two temperature sensors for the measured gas temperature, .: ' : .
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M&T, are checked. If one is out of the reasonable ranye, the fault information is stored in the memory at block 166.
If both temperature sensor outputs are faulty, the APU is shut down at block 160.
The fault program continues in Figure 11. At block 5 the load compressor oil pressure is checked. If it is excessive~ the load compressor inhibit flag is set at 171 and the fault information recorded in the memory at block 172. If the load compressor oil pressure is low at bloclc 173, the APU is shut down at block 174. If the oil pressure is not low, a time delay is provided by blocks 175~ 176 and 177. At block 178 the APU is enabled, with the load compressor unloaded. Generator 43 is driven to supply electrical loads.
The check of faults continues in Figure 12. IE the start flag is set at block 180, the ready to load ~load compressor) is removed and a shutdown command given at block 181. The unload flag is set at block 182 and load compressor protective steps taken at block 183. The sytem proceeds to shut down at block 184 and also checks the engine compressor surge valve at block 185.
If the start flag was not set at block 180, and the ready to load flag is set at block 186, the ready to load indication is given to the aicraft at block 187. At block 188 the APU is enabled and the program proceeds to load compressor protection block l83. Again, if the compressor is ready to operate, shutdown 184 is bypassed and the program continues as will be described below. If the RTL
flag is not set at block 18~, power turbine speed is checlced at 190. If the speed is below 95% the program proceeds to blocks 181, 182 and 183 as described above. If the flag is set, the RTL count is checked at 191. If the count is complete~ the program continues through block 192 to block 187. If the count is incomplete, the program continues to block 181.
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Assuming that the load compressor protection checks are favorable, a series of checks are conducted to determine whether the APU will be shut down or w:ill continue to operate. These include loss of DC at block 194 and excessive ~3 measured ~as temperature at block 195, low oil pressure at block 196, sequencying failure at bloclc 197, normal shutdown procedure, block 198~xshutdown circuit /
failure a-t block 199. Failure of any of these tests ~s the program proceeds to shut down at block 184.
Figure 13 illustrates the shutdown sequence. The condition of the fuel metering valve inhibit flag indicates whether the shutdown is normal or fault caused. It is checked at block 202. If it is set, all outputs of the APU
except that to the fuel metering valve are disabled. I the inhibit flag is not set~ a fault indication is provided to the aircraft and all APU outputs are disabled in block 205.
At block 206 various APU sensor circuits are disabled, including low oil pressure, sequency failure, underspeed and ~lameout. At block 207 if the shutdown enable flag is set, the gas producer speed is checked at block 208. If it is less than 8~ of rated speed, a signal that the APU is shut down is given to ~he aircraft, block 209. The program continues to block 210 which checks the absence of a start command and gas producer speed less than 8%. If both conditions are not presen~, the program continues to block 211 for another cycle of the watchdog timer. If both conditions are present, block 212 stores shut down system information in the memory. Power to the controller is removed at block 213. At block 2l4 if the power has been properly removed, the program proceeds to bloclc 215 to wait for the next startup command. If power is not properly removed, block 216 indicates a fault in the aircraEt systems which is entered in the memory at block 217.
The fault store sequence for the memory is illustrated in Figure 14. Fault information is temporarily stored in a register, block 220. At block 221 it is determined whether 3 ~ ~
the fault is serious enough to cause a shutdown o. the APU.
If it is not, block 222 selects a memory pointer number 2 which is incremented in block 223 and the fault information stored at block 224. If the fault caused a shutdown, pointer No. 1 is selected at blcck 225, incremented at 226 and the fault identification stored at the appropriate location, block 224.
An outline of the passive test is provided by the diagram of Figure 15. Internal voltage checks are made at block 227. If any voltage check is bad, the APU is shut down, block 228, Figure 13. If the internal voltage checks are good, a series of other passive checks are made. At block 229, the oil quan~ity in the load compressor is checked. If it is low, the procedure proceeds to a time delay 230 and when i-t is complete as determined at block 231, a low oil quantity output signal is given to the aircraft, block 232.
Correlation of the control and position Eeedback signals for the fuel metering valve 33 is checked at block 234. If they do not agree, the program proceeds to shut down at block 228. Ir they do agree, the next check is of the correlation of the surge valve actuator and position feedback. Here if they do not agree, the fault information is stored at 236. The compressor inlet guide vane actuator and feedback position are checked a~ 237 and if not in agreement, the fault information is stored at 238. Control functions of the control processor 52 which clo not cause a shutdown/ are checked at 239. Faults found are stored at 240. The passive test repeats so long as the APU is operative.
The active BITE system is enabled with APU shutdown, and is activated by operator control of a test switch, Figure 16. System interrupts are disabled at clock ~ so that the tes-t program can be carried out. At block 246 the light emitting diodes of the visual display are all turned on so that the display may be checked by the operator. The ~1~83~
~14-message "test in progress" is then displayed, block 247, while the active test continues. Control functions, the operation of the control processor 52, are checked at block 248 (Figure 18). Any failure is communicated to and presented by display 56, followed by the legend "Controller Failure", blocks 249, 250. Following a check oE the control functions, the protective functions of protection processor 53 are checked, block 251 (Figure 17). A failure is similarly indicated by the displays of blocks 249, 250.
Following check of the control and protective functons/ block 252 (Figure 19) isolates the line replaceable unit (LRU) or other component of the APU which has failed. At block 253, 254, the present and previous shutdown causes are displayed. A "Test Complete" display completes the process, block 255.
A check of protective functions in protection processor 53 is illustration in Figure 17. At block 260 the inputs to the protection processor 53 are stimulated successively and the resulting input signals are read at 20 block 261. If there is disagreement, the conclusion is that the controller has fai:Led, block 262 and this information is displayed at block 263. If the inputs and the input signals are in agreement, block 264 detects unit or aircraft harness failures which are stored at block 265. Output commands from the protection processor are injected at block 266 and read with an analog/digital converter at 2~7. Again, a failure in the outputs indicates that the controller has failed and this information is transmitted to block 262 and displayed at 263. If the outputs are appropriate, block 268 detects aircraft harness problems in the output circuits.
Information regarding a failed replaceable unit is stored at 269. Finally the software of the protection processor is checked at block 27û by stimulating program modules separately. The outputs actuated thereby are also checked.
A failure is detected as a failed controller, block 262. In the absence of failure, block 271 determines that the protective functions are operating.
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In Figure 18 the control functions oE control processor 52 are checked by stimulating the lnputs at block 275. At block 276 the inputs are checked using the handshake connection with the control processor to interrogate the related control functions. A failure of any of these checks indica~es that the controller has failed, biock 277, and this information is displayed at 278. If the checks indicate the control functions and inputs are satisfactory, block 279 checks for a failed APU replaceable unit or an aircraft harness problem~ Failure information is stored at 280.
Control function outputs are provided from the protection processor 53 to control processor 52 through the handshake connection, at block 281. If the signals from the analog to digital converter are not correctr a control processor failure is indicated at 282 and communicated though block 277 to display 278. A failed APU unit associated with the output of the controller processors, or an aircraft harness failure is detected at block 283 and recorded at block 284. The control processor functions are checked through the handshake connection at block 285. A
failure is displayed at block 278~ If -the controller functions properly, this is verified at block 286.
Figures 21, 22 and 23 illustrate the typical circuits ~or checking the APU actuator elements and the processor input circuits. In E'igure 21 protection processor 53 actuates a driver 290 in the output of the control processor 52. The driver is connected through circuit 291 with an APU
actuator element 293 and a power supply. A voltage sensing circuit 294 is connected acros5 the driver and a current sensing circuit 295 is connected in series therewith.
Outputs of the sensing circuits are connected through a multiplexer 296 with a protection processor input and an analog to digital converter. The voltage and current conditions in the circuit are analyzed to determine whether the actuator element and the interconnecting circuit 291 and 3 ~ ~
driver 290 are operating properly. With the voltage and current information, the nature of a fault in the driver, actuator element or interconnecting circuit can be determined.
In Figure 22, the circuit for stimulating a speed sensor inpu-t is illustrated~ The signal from an oscillator 300 is connected through a switch 301 controlled by the protection processor to a frequency/digital converter 302 in the control processor 303. Other processor input circuits are provided with a suitable signal, as an analog signal~
from the protection processor 53,/t~ ough a demultiplexer 305 having outputs connected with the various input circuits 306 of control processor 52. Similar circuits may be used to test the inputs of the protection procesor 53.
In Figure 19, the program Eor isolating the Eailed replaceable unit of the APU is illustrated, block 252, Figure 16. At hlock 310, information regarding APU
shutdowns is derived from memory 55, Figure 2. If this information identifies the unit which has failed, this situation is determined at block 311 and the appropriate information displayed at block 312. If the failed unit is not indicated directly by the shutdown information in the memory, block ~ analyzes the various information available to determine the failed unit. At block 313, if the information available identifies ~he failed unit, this is displayed at block 312. If the unit cannot be isolated, then the symptoms of the system which occurred at shutdown are selected by block 314 and displayed along with aircra~t harness problems at block 315.
Figure 20 is the flow diagram for clearing the memory, block 121, Figure 6. At block 318, zeros are written in all memory location. Block 319 then initiates a display l'NVM
Cleared'l~ The display is maintained so long as the clear button is depressed, block 320.
Nonvolatile memory 55 is operated to retain data when the power is removed. l~he memory action depends on a ~83~0 trapped injected charge and each bit of storage is a duel transistor pair. Ones and zeros are entered by forcing one of each pair to a high impedance state and the other to a low impedance state. Inputs to the memory are isolated during power up and power down of the APU so that the stored data is not affected by transients.
TEST SYSTEM FOR A DYNAMIC MACHINE
Specification This invention is concerned with a test system or a dynamic machine or the like in which fault conditions are recognized and recorded to aid in servicing.
The invention is illustrated with an auxiliary power unit tAPU~ for an aircraEt, and some of the features o the system disclosed are particularly suited therefor. Other features of the invention are of more general application and can be used in the protection and testing of other dynamic machines.
A general discussion of the construction and operation of an APU will aid in appreciation of the problems of the prior art and an understanding of the significance of the invention. A typical APU includes an engine which drives a generator and a compressor to provide electrical power for selected loads and compressed air for environmental and other purposes, when the aircraft is on the ground. The APU
is also operated in an emergency when the aircraft is airborne to supplement or replace faulty equipment. The APU
en~ine uses jet fuel which is burned to form a gas that operates a turbine to drive the generator and the compressor. Various conditions of the APU are sensed to provide inputs to a controller which controls the fuel to the APU, other Eunctions related to the APU and which shuts the APU down in the event of a malfunction.
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~5~31~
Prior APU test systems have monitored sensed APU
conditions. Upon the occurrence of a condition which is out of tolerance, an indication of a unit failure is given, based on a statistical analysis of probable cause. This is unsatisfactory in practice as the inclicated probable cause is at best an educated guess. Furthermore, the statistical failure analysis made during development of a dynamic machine is not accurate for a mature system. Service personnel have learned that the test system fault indications are unreliable and often ignore them.
A principal feature of the invention is the provision of a test system which monitors individual components of a dynamic machine and identifies faults. When a fault occurs that causes a shutdown, the test system determines the shutdown cause. The test system includes a memory in which the identity of the faulty element is stored. A visual display is connected with the memory and displays the stored fault information.
One feature of the invention is the prov:ision of a ~0 passive test system which monitors outputs of the machine condition sensors and various controller parameters.
Another feature is the provision of an active test system which checks sensors and actuating elements that cannot be checked when the machine is operating, stimulates control outputs and checks the actuating elements and which supplies inputs to the machine control and checks Eor appropriate responses.
A further feature of the invention is that fault information including information regarding the cause of plural successive shutdowns is stored in a me~ory and available through a visual display.
Further features and advantages of the invention will readily be apparent from the following specification and Erom the drawings, in which:
~ ~5~310 Figure 1 is a diagrammatic perspective illustration ~f an aircraft auxiliary power unit Figure 2 is a general block diagram of the APU control and protection circuits;
Figure 3 is a detailed block diagram of the APU with condition sensors and actuator elements relevant to an understanding of the invention;
Figures 4 and 5 are flow charts for the passive an~
active test systems, respectively;
Figure 6 is a flow chart for the protective functions;
Figure 7 is a flow chart for the operation of the protective functions;
Figure 8 is a flow chart for the initialization procedure, Figure 9 is a flow chart for the status procedure;
Figures 10, 11 and 12 are flow charts Eor the processor on occurrence of a fault;
Figure 13 is a flow chart for the shutdown procedure;
Figure 14 is a flow chart illustrating storage of fault information in the memory, Figure 15 is a flow chart of the passive test system;
Figure 16 is a flow chart of the active test system display routine;
Figure 17 is a flow chart for the check of protective functions which is a part of the active test system;
Figure 18 is a flow diagram for the check of control functions which is a part of the active test system;
Figure 19 is a flow chart for the isolation of a deLective unit which is a part of the active test system;
Figure 20 is a flow chart for the procedure of clearing of the memory;
Figure 21 is a block diagram of a circuit for stimulating an output of the machine control;
Figure 22 is a block diayram illustrating the application of an AC stimulating signal to an input of the machine control; and ~ ~583~) Fi~ure 23 is a ~lock dia~ram illustrating the appli~
cation of a DC stimulating signal to an input of the machine control.
The auxiliary power unit - APU - of Figure 1 and 2 is an illustration of a controlled dynamic machine with which the test system of the invention is particularly use~ul. Glennon U.S. Patent No. ~,118,688, October 3, 1978, shows a prior test system used with an aircra-Et electrical generator driven by a constant speed drive, an illustration of another controlled dynamic machine with which the inven*ion is useful. There are other dynamic machines or apparatus of greater or lesser com-plexity for which the passive and active tes-t systems and ~ault recording is useful.
The term "dynamic machine", or "controlled dynamic machine", is used herein to designate an appara-tus which has active func*ions, as star~ing, operating and stopping, as direct-ed by actuator elements. Sensors or operator controls, or a combination thereof, provide in~ormation to a machine control which in turn generates control signals that are direc-ted to the actuator elements. The nature of the opera-tion of the machine is often estahlished in accordance with a predetermined function or program based on the input in~ormation from the sensors or from an operator.
The auxiliary power unit 30 illustrated diagram~atically in Figure 1 is powered by a -turbine engine 31 which uses air-craft jet fuel. The fuel is delivered from an aircraft fuel system through line 32 and fuel pump 35 to fuel metering valve 33 which controls *he fuel flow to the APU. A solenoid operat-ed valve 34 affords an on-off control of the APU. Fuel is delivered from pump 35 to a ~as chamber 37 in which the fuel is .~
1 mixed with air from engine compressor 38 and burned to generate gas which drives the turbine 31. The AP~ is started ~y a battery powered motor (not shown) which drives the engine compressor 38. At the appropriate speed, fuel valve 34 and metering valve 33 are opened delivering fuel to the gas producer where it is ignited.
~: ' ,,:
~ .
; ' ~ ' `
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, ~83~
The turbine shaft 40 is connected throu~h gearing indicated generally at 41 to drive an air compressor 42 and a three-phase electrical generator 43. ~ir inlet duc~s 45, 46 and 47 direct air to the gas generator compressor, compressor 38, compressor 42 and to a cooling fan 48 which circulates air through the APU compartment of the aircraft.
Air from compressor 42 is utilized in the a.ircraEt environmental system, e.g., to circulate fresh air through the cabin, for main engine starting and for powering an emergency hydraulic pump. Other apparatus capable of being operated by compressed air may also be connected with the compressor.
Generator 43 provides electrical power to loads, as lights, controls, communication equipment and the :Like when the aircraft is on the ground. The APU may be ope:rated when the aircraft is airborne and the generator 43 may be connected to supplement the e:Lectrical supply, as when one of the main generators is inoperative.
The APU controller 50 illustrated in bloelc form in Figures 2 and 3 is preferably a programmed microprocessor which responds to inputs from sensors in the APU and from the aircraft, providing outputs to APU actuator elements and to operation displays in the aireraftO The control.ler 50 is divided into two portions, a control processor 52 and a protection processor 53. The control processor is in charge of the start-up and operation of the APU. The protection processor detects faults, orders ~PU shutdown and tests the system.
The protection processor 53 is eonnected through a multiplexer 54 with the APU sensors and actuator elements and the control processor inputs to conduct tests, as will appear. When a fault is detected, the identlty of that fault is communicated from the protection processor 53 to a fault indicating memory 55. The serviceman can call up the recorded fault information on a v.isual fault display 56.
3 ~ Q
The APU and aircraft interconnection with the controller is shown in more detail in Figure 3. APU sensor inputs to the controller 50 include:
61 - incoming fuel temperature T~
62 - gas producer compressor, dis-charge pressure CDP
63, 63'- gas producer speed sensors NG
#1, ~2 (two speed sensors are used for added reliability) 64 - measured gas temperature - MGT -in the gas producer 65, 65l_ power turbine speed sensors Npt #1 and #2 67 - differential pressure QP in lS the load compressor 42 68 - inlet pressure PIN for the load compressor 69 - output pressure PoUT for the load compressor 70 - low oil pressure - LOP - in the load compressor 71 - high oil temperature - HOT -in the load compressor 72 - low oil quantity - LO~ - in the load compressor.
Outputs Erom the electronic controller 50 are connected with the following APU actuator elements:
~5 - rotary actuator for fuel meter-ing valve 33 sets the fuel flow to the APU. A valve position feedback 75 provides an input to electronic controller 50 com-pleting a servo loop for the fuel valve 1~5~3~
76 start contactor provides elec-trical power to the start motor (not shown) 77 - igniter ignites the fuel in the gas producer 78 - surge valve actuator opens a by-pass valve~on the load compres~
-~ sor 42 to minimize a surge con-dition. Valve position feedback 8~ c c~7~ ~c7~c s ;~ lcti~ a servo loop with actuator 78 for the surge valve 81 - inlet guide vane actuator for the inlet guide vanes of the load compressor. Inlet guide vane position feedback 82 com-pletes a servo loop for the in-let guide vane actuator.
Additional inputs to electronic controller 50 include:
85 - ambient temperature~ ~amb 86 - Start/On command from the air-craft 87 - AIR/GROUND signal from the air-craft 88 - a signal indicating the status of the main aircraft electrical generating system 89 - main engine start signal.
Other outputs of electronic controller 50 include the following display signals to the aircraft:
92 - load compressor unload 93 - APU fault 94 - APU shutdown 831~
95 - APU ready to load 9G - gas temperature for a meter display.
The invention is concerned wi~h the test system and its relation to the protection processor 53. Accordingly, the programming of control processor 52 will not be considered in detail. It is sufficient to understand that upon initiation of the APU operation the start motor is energized to drive engine compressor 38, the igniter is turned on and fuel valve 34 opened. These operations are controlled sequentially primarily on the basis o gas producer speed NG and time delays. For shutdown, the fuel valves are closed.
The opera-tion of the passive and active test systems will be described, primarily with reference to the program flow diagrams, Figures 4-20, which represent the protection and test programs performed by protection processor 53.
A principal feature of the invention is the provision of passive and active test systems with a memory which records faulty components and the causes of shutdown before subsequent display. The operation of these test systems is illustrated diagrammatically in Figures 4 and 5.
The passive test, Figure 4, functions con-tinually during operation of the auxiliary power unit. At block 100 passive identification of nonshutdown faults is conducted.
Any faults that are noted are stored at block 101 in the nonvolatile memory 55. In the event o~ a shutdown, the passive system identifies the cause at block 102. IE a shutdown is indicated at block 103, the pertinent symptoms are identified at block 104 and recorded in the memory 55 at block 105. If shutdown is not indicated, the program returns ~rom block 103 to block 100 and continues.
The active test is manually initiated following an APU
shutdown as indicated at block 107, Figure 5. At block 108 controller 50, its various inputs, the APU sensors and the 3 ~ ~
~9 APU actuating element, all shown in ~igure 3, are checked.
At block lOg a determination is made whether the controller is functioning properly. If it is, a check is made at block 110 of the aircraft inputs and APU sensor signals. The results of this check and of previous shutdown causes is displayed at 111. If a unit of the APU which is replaceable on the flight line (LRU) can be isolated, this inEormation is displayed at block 112. If the controller is determined to be inoperative, block 109, this information and the causes oE previous shu~downs are displayed at bloclc 113/
followed by a display that the controller has failed, bloclc 114.
The overall protective function flow chart is shown in Figure 6. Following power up and initialization of the APU
at block 118, fault checks are made at block 119 and operation of the passive test system commences at block 120. The active test sytem is checked and the memory cleared at block 121.
Figure 7 shows in more detail the steps included in the protective functions. Following power up block 124 and initialization of the system block 125 (see Figure 8 below~, a determination is made at block 126 whether the gas producer speed NG is below or above 8% oE operating speed. If the speed is less than 8~, the system status i5 checked at block 127 (see Figure 9 below). IE the gas producer speed is greater than 8%, the passive test system, block 128, is made operative.
The initialization procedure, Figure ~ precedes the startup of operation of the APU~ All system outputs are disabled at bloclc 130. Then all data and program flags are reset at block 131. The watchdog timer WDT Eor the controller is tested at 132 and a determination is made whether it is operating properly at bloek 133. WDT cycles periodically. If a system failure prevents its operation~
3S the APU is shut down, block 134. If the watchdog timer operates properly, the controller counters are reset or ~1~83~
initialized at 135. The Erequency to digital F/D signal converters which operate with the speed sensors 63, 63' and 65, 65l are started at block 136. The system clock is started at block 137 and the system interrupts are enabled at block 138. This completes the initialization procedures.
~ he system status program, block 127, Figure 7, is illustrated in Figure 9. After determining the status of manual switches at block 142, the BITE button is checked at block 143, and if it has been actuated the active ~est system is initiated at block 144, see Figure 16. If the ~ITE button is not actuated, the clear button is checked and if it is actuated the memory is cleared at block 146, see Figure 20. If there has been a momentary loss of DC power r the check at block 147 will shut the ~PU down, block 148.
The system can be restarted only after manual actuation of the ON/OFF switch.
Figures 10, 11 and 12 illustrate the tests perEormed to detect the occurrence of a fault. In Figure 10, at block ~so the analog/~ controller inputs are checked. These include, for exampleJ temperature and pressure sensors in the APU. At block 151 the status of input is checked. At block 152, control functons of the control processor 52 are obtained through the handshake connection, Figure 2c At block 153 checks are made of the speed Erom the various APU
speed sensors. At block 154 a fire condition is checked;
and at block 155 the position of the inlet door ls examined. At block 156 the engine compressor discharge pressure is checked. Block 157 examines the load compressor oil pressure while block 158 checks the load compressor oil temperature. In each oE blocks 154-158, if a Eault condition is detected, the APU is shut down at block 160.
The ambient temperature is checked at 161. IE the reading is not reasonable, a fault identiEication is stored at block 162, see Figure 14. Similarly, fuel temperature Tf is checked at block 163. Blocks 164, 165, the outputs of two temperature sensors for the measured gas temperature, .: ' : .
.
3 ~ ~
M&T, are checked. If one is out of the reasonable ranye, the fault information is stored in the memory at block 166.
If both temperature sensor outputs are faulty, the APU is shut down at block 160.
The fault program continues in Figure 11. At block 5 the load compressor oil pressure is checked. If it is excessive~ the load compressor inhibit flag is set at 171 and the fault information recorded in the memory at block 172. If the load compressor oil pressure is low at bloclc 173, the APU is shut down at block 174. If the oil pressure is not low, a time delay is provided by blocks 175~ 176 and 177. At block 178 the APU is enabled, with the load compressor unloaded. Generator 43 is driven to supply electrical loads.
The check of faults continues in Figure 12. IE the start flag is set at block 180, the ready to load ~load compressor) is removed and a shutdown command given at block 181. The unload flag is set at block 182 and load compressor protective steps taken at block 183. The sytem proceeds to shut down at block 184 and also checks the engine compressor surge valve at block 185.
If the start flag was not set at block 180, and the ready to load flag is set at block 186, the ready to load indication is given to the aicraft at block 187. At block 188 the APU is enabled and the program proceeds to load compressor protection block l83. Again, if the compressor is ready to operate, shutdown 184 is bypassed and the program continues as will be described below. If the RTL
flag is not set at block 18~, power turbine speed is checlced at 190. If the speed is below 95% the program proceeds to blocks 181, 182 and 183 as described above. If the flag is set, the RTL count is checked at 191. If the count is complete~ the program continues through block 192 to block 187. If the count is incomplete, the program continues to block 181.
3 ~ ~
Assuming that the load compressor protection checks are favorable, a series of checks are conducted to determine whether the APU will be shut down or w:ill continue to operate. These include loss of DC at block 194 and excessive ~3 measured ~as temperature at block 195, low oil pressure at block 196, sequencying failure at bloclc 197, normal shutdown procedure, block 198~xshutdown circuit /
failure a-t block 199. Failure of any of these tests ~s the program proceeds to shut down at block 184.
Figure 13 illustrates the shutdown sequence. The condition of the fuel metering valve inhibit flag indicates whether the shutdown is normal or fault caused. It is checked at block 202. If it is set, all outputs of the APU
except that to the fuel metering valve are disabled. I the inhibit flag is not set~ a fault indication is provided to the aircraft and all APU outputs are disabled in block 205.
At block 206 various APU sensor circuits are disabled, including low oil pressure, sequency failure, underspeed and ~lameout. At block 207 if the shutdown enable flag is set, the gas producer speed is checked at block 208. If it is less than 8~ of rated speed, a signal that the APU is shut down is given to ~he aircraft, block 209. The program continues to block 210 which checks the absence of a start command and gas producer speed less than 8%. If both conditions are not presen~, the program continues to block 211 for another cycle of the watchdog timer. If both conditions are present, block 212 stores shut down system information in the memory. Power to the controller is removed at block 213. At block 2l4 if the power has been properly removed, the program proceeds to bloclc 215 to wait for the next startup command. If power is not properly removed, block 216 indicates a fault in the aircraEt systems which is entered in the memory at block 217.
The fault store sequence for the memory is illustrated in Figure 14. Fault information is temporarily stored in a register, block 220. At block 221 it is determined whether 3 ~ ~
the fault is serious enough to cause a shutdown o. the APU.
If it is not, block 222 selects a memory pointer number 2 which is incremented in block 223 and the fault information stored at block 224. If the fault caused a shutdown, pointer No. 1 is selected at blcck 225, incremented at 226 and the fault identification stored at the appropriate location, block 224.
An outline of the passive test is provided by the diagram of Figure 15. Internal voltage checks are made at block 227. If any voltage check is bad, the APU is shut down, block 228, Figure 13. If the internal voltage checks are good, a series of other passive checks are made. At block 229, the oil quan~ity in the load compressor is checked. If it is low, the procedure proceeds to a time delay 230 and when i-t is complete as determined at block 231, a low oil quantity output signal is given to the aircraft, block 232.
Correlation of the control and position Eeedback signals for the fuel metering valve 33 is checked at block 234. If they do not agree, the program proceeds to shut down at block 228. Ir they do agree, the next check is of the correlation of the surge valve actuator and position feedback. Here if they do not agree, the fault information is stored at 236. The compressor inlet guide vane actuator and feedback position are checked a~ 237 and if not in agreement, the fault information is stored at 238. Control functions of the control processor 52 which clo not cause a shutdown/ are checked at 239. Faults found are stored at 240. The passive test repeats so long as the APU is operative.
The active BITE system is enabled with APU shutdown, and is activated by operator control of a test switch, Figure 16. System interrupts are disabled at clock ~ so that the tes-t program can be carried out. At block 246 the light emitting diodes of the visual display are all turned on so that the display may be checked by the operator. The ~1~83~
~14-message "test in progress" is then displayed, block 247, while the active test continues. Control functions, the operation of the control processor 52, are checked at block 248 (Figure 18). Any failure is communicated to and presented by display 56, followed by the legend "Controller Failure", blocks 249, 250. Following a check oE the control functions, the protective functions of protection processor 53 are checked, block 251 (Figure 17). A failure is similarly indicated by the displays of blocks 249, 250.
Following check of the control and protective functons/ block 252 (Figure 19) isolates the line replaceable unit (LRU) or other component of the APU which has failed. At block 253, 254, the present and previous shutdown causes are displayed. A "Test Complete" display completes the process, block 255.
A check of protective functions in protection processor 53 is illustration in Figure 17. At block 260 the inputs to the protection processor 53 are stimulated successively and the resulting input signals are read at 20 block 261. If there is disagreement, the conclusion is that the controller has fai:Led, block 262 and this information is displayed at block 263. If the inputs and the input signals are in agreement, block 264 detects unit or aircraft harness failures which are stored at block 265. Output commands from the protection processor are injected at block 266 and read with an analog/digital converter at 2~7. Again, a failure in the outputs indicates that the controller has failed and this information is transmitted to block 262 and displayed at 263. If the outputs are appropriate, block 268 detects aircraft harness problems in the output circuits.
Information regarding a failed replaceable unit is stored at 269. Finally the software of the protection processor is checked at block 27û by stimulating program modules separately. The outputs actuated thereby are also checked.
A failure is detected as a failed controller, block 262. In the absence of failure, block 271 determines that the protective functions are operating.
3 `~ ~
In Figure 18 the control functions oE control processor 52 are checked by stimulating the lnputs at block 275. At block 276 the inputs are checked using the handshake connection with the control processor to interrogate the related control functions. A failure of any of these checks indica~es that the controller has failed, biock 277, and this information is displayed at 278. If the checks indicate the control functions and inputs are satisfactory, block 279 checks for a failed APU replaceable unit or an aircraft harness problem~ Failure information is stored at 280.
Control function outputs are provided from the protection processor 53 to control processor 52 through the handshake connection, at block 281. If the signals from the analog to digital converter are not correctr a control processor failure is indicated at 282 and communicated though block 277 to display 278. A failed APU unit associated with the output of the controller processors, or an aircraft harness failure is detected at block 283 and recorded at block 284. The control processor functions are checked through the handshake connection at block 285. A
failure is displayed at block 278~ If -the controller functions properly, this is verified at block 286.
Figures 21, 22 and 23 illustrate the typical circuits ~or checking the APU actuator elements and the processor input circuits. In E'igure 21 protection processor 53 actuates a driver 290 in the output of the control processor 52. The driver is connected through circuit 291 with an APU
actuator element 293 and a power supply. A voltage sensing circuit 294 is connected acros5 the driver and a current sensing circuit 295 is connected in series therewith.
Outputs of the sensing circuits are connected through a multiplexer 296 with a protection processor input and an analog to digital converter. The voltage and current conditions in the circuit are analyzed to determine whether the actuator element and the interconnecting circuit 291 and 3 ~ ~
driver 290 are operating properly. With the voltage and current information, the nature of a fault in the driver, actuator element or interconnecting circuit can be determined.
In Figure 22, the circuit for stimulating a speed sensor inpu-t is illustrated~ The signal from an oscillator 300 is connected through a switch 301 controlled by the protection processor to a frequency/digital converter 302 in the control processor 303. Other processor input circuits are provided with a suitable signal, as an analog signal~
from the protection processor 53,/t~ ough a demultiplexer 305 having outputs connected with the various input circuits 306 of control processor 52. Similar circuits may be used to test the inputs of the protection procesor 53.
In Figure 19, the program Eor isolating the Eailed replaceable unit of the APU is illustrated, block 252, Figure 16. At hlock 310, information regarding APU
shutdowns is derived from memory 55, Figure 2. If this information identifies the unit which has failed, this situation is determined at block 311 and the appropriate information displayed at block 312. If the failed unit is not indicated directly by the shutdown information in the memory, block ~ analyzes the various information available to determine the failed unit. At block 313, if the information available identifies ~he failed unit, this is displayed at block 312. If the unit cannot be isolated, then the symptoms of the system which occurred at shutdown are selected by block 314 and displayed along with aircra~t harness problems at block 315.
Figure 20 is the flow diagram for clearing the memory, block 121, Figure 6. At block 318, zeros are written in all memory location. Block 319 then initiates a display l'NVM
Cleared'l~ The display is maintained so long as the clear button is depressed, block 320.
Nonvolatile memory 55 is operated to retain data when the power is removed. l~he memory action depends on a ~83~0 trapped injected charge and each bit of storage is a duel transistor pair. Ones and zeros are entered by forcing one of each pair to a high impedance state and the other to a low impedance state. Inputs to the memory are isolated during power up and power down of the APU so that the stored data is not affected by transients.
Claims (6)
1. In a dynamic machine having a plurality of sensors providing signals representative of operating conditions of the machine, a machine control responsive to said condition signals for generating control signals for the operation and shutdown of said machine on command or on occurrence of a fault condition, and actuator elements responsive to said control signals to operate and shut down the machine, an improved test system com-prising:
a processor programed to provide an active test system operative when the machine is shut down, with means for checking said sensors and said actuator elements for detecting the cause of a fault; and means for recording the detected cause of the fault.
a processor programed to provide an active test system operative when the machine is shut down, with means for checking said sensors and said actuator elements for detecting the cause of a fault; and means for recording the detected cause of the fault.
2. The test system of claim 1 in which said active test system includes:
means for applying stimulating signals representing said condition responsive signals to said machine control;
means for monitoring the outputs of the machine control to determine whether they are correct for the stimulating signals applied thereto.
means for applying stimulating signals representing said condition responsive signals to said machine control;
means for monitoring the outputs of the machine control to determine whether they are correct for the stimulating signals applied thereto.
3. The test system of claim 1 for a dynamic machine in which the machine control includes a programed data processor and said test system includes means for checking the operation of said program.
4. In combination with a dynamic machine that includes sensors providing signals representative of operating condi-tions of the machine, a programed operating controller respon-sive to the condition signals for generating control signals
4. In combination with a dynamic machine that includes sensors providing signals representative of operating condi-tions of the machine, a programed operating controller respon-sive to the condition signals for generating control signals
Claim 4 continued....
for the operating and shutdown of said machine on command or on occurrence of a fault condition, and actuator elements respon-sive to said control signals to operate and shut down the machine, an improved test system comprising:
a processor programed to provide a passive test system operative during operation of the machine for monitoring said sensors to detect a failure thereof and for monitoring selected controller parameters to detect occurrence of a fault condition, and an active test system operative when the machine is shut down to detect the cause of a shutdown;
a memory connected with said passive and active test systems to record the identity of failed sensors and the cause of a machine shutdown; and a visual display connected with said memory for dis-playing the identity of failed sensors and the cause of ma-chine shutdown.
for the operating and shutdown of said machine on command or on occurrence of a fault condition, and actuator elements respon-sive to said control signals to operate and shut down the machine, an improved test system comprising:
a processor programed to provide a passive test system operative during operation of the machine for monitoring said sensors to detect a failure thereof and for monitoring selected controller parameters to detect occurrence of a fault condition, and an active test system operative when the machine is shut down to detect the cause of a shutdown;
a memory connected with said passive and active test systems to record the identity of failed sensors and the cause of a machine shutdown; and a visual display connected with said memory for dis-playing the identity of failed sensors and the cause of ma-chine shutdown.
5. The test system of claim 3 in which programed data processor has a control function and a protective function and said test system includes means for checking the operation of both said control function and said protective function.
6. The test system of claim 1 including:
means for determining whether the cause of a fault condition is in said machine control or in an operating condi-tion sensor or an actuator element; and means for recording and indicating the results of such determination.
means for determining whether the cause of a fault condition is in said machine control or in an operating condi-tion sensor or an actuator element; and means for recording and indicating the results of such determination.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US1873979A | 1979-03-08 | 1979-03-08 | |
| US018,739 | 1979-03-08 |
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|---|---|
| CA1158310A true CA1158310A (en) | 1983-12-06 |
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ID=21789547
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000341813A Expired CA1158310A (en) | 1979-03-08 | 1979-12-13 | Test system for a dynamic machine |
Country Status (7)
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| JP (1) | JPS55119038A (en) |
| CA (1) | CA1158310A (en) |
| DE (1) | DE2948784A1 (en) |
| FR (1) | FR2451027A1 (en) |
| GB (1) | GB2044485B (en) |
| IL (1) | IL59320A (en) |
| SG (1) | SG19784G (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BG32121A1 (en) * | 1980-07-04 | 1982-06-15 | Gradinarov | Apparatus for checking of periodic processes |
| JPS5810246A (en) * | 1981-07-13 | 1983-01-20 | Nissan Motor Co Ltd | Digital controller for vehicle |
| DE3229411A1 (en) * | 1981-08-06 | 1983-03-03 | Nissan Motor Co., Ltd., Yokohama, Kanagawa | Electronic device with self-monitoring for a motor vehicle |
| GB2124794A (en) * | 1982-08-06 | 1984-02-22 | Technology Transfer Services L | Monitoring system |
| GB2125578A (en) * | 1982-08-16 | 1984-03-07 | Nissan Motor | Self monitoring system |
| GB2125577B (en) * | 1982-08-16 | 1986-09-24 | Nissan Motor | Self monitoring system |
| US4897184A (en) * | 1986-10-31 | 1990-01-30 | Cobe Laboratories, Inc. | Fluid flow apparatus control and monitoring |
| AU6157599A (en) * | 1998-09-21 | 2000-04-10 | Master Tech Engineering, Inc. | Event recorder |
| CN102343983A (en) * | 2011-07-07 | 2012-02-08 | 中国国际航空股份有限公司 | Airplane APU (Auxiliary Power Unit) performance detecting method |
| CN103543029B (en) * | 2013-11-05 | 2016-06-01 | 中国航空工业集团公司西安飞机设计研究所 | A kind of monitoring analysis method for main control system of whole plane fatigue test |
| CN103616183A (en) * | 2013-12-05 | 2014-03-05 | 哈尔滨工程大学 | Marine-diesel-engine general-parameter monitoring device and method based on virtual instrument |
| CN107402133B (en) * | 2017-07-21 | 2019-08-23 | 芜湖赛宝机器人产业技术研究院有限公司 | A kind of Novel industrial robot servo-driver Performance Test System and test method |
| CN117623207B (en) * | 2023-11-28 | 2026-01-30 | 浙江中烟工业有限责任公司 | A paste dispensing system and its fault feedback design method |
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|---|---|---|---|---|
| US3704363A (en) * | 1971-06-09 | 1972-11-28 | Ibm | Statistical and environmental data logging system for data processing storage subsystem |
| US4118688A (en) * | 1977-07-08 | 1978-10-03 | Sundstrand Corporation | Confidence check circuit for built-in test systems |
| US4116052A (en) * | 1977-09-19 | 1978-09-26 | Semco Instrument, Inc. | Jet engine test set |
-
1979
- 1979-12-04 DE DE19792948784 patent/DE2948784A1/en not_active Withdrawn
- 1979-12-13 CA CA000341813A patent/CA1158310A/en not_active Expired
-
1980
- 1980-01-31 FR FR8002084A patent/FR2451027A1/en active Granted
- 1980-02-05 IL IL5932080A patent/IL59320A/en unknown
- 1980-03-04 GB GB8007230A patent/GB2044485B/en not_active Expired
- 1980-03-04 JP JP2621180A patent/JPS55119038A/en active Pending
-
1984
- 1984-03-01 SG SG19784A patent/SG19784G/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55119038A (en) | 1980-09-12 |
| DE2948784A1 (en) | 1980-09-18 |
| FR2451027A1 (en) | 1980-10-03 |
| IL59320A (en) | 1984-08-31 |
| GB2044485B (en) | 1983-11-16 |
| SG19784G (en) | 1985-01-04 |
| GB2044485A (en) | 1980-10-15 |
| FR2451027B1 (en) | 1983-11-10 |
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