GB2138979A

GB2138979A - Testing vehicle instrumentation system

Info

Publication number: GB2138979A
Application number: GB08407637A
Authority: GB
Inventors: Alan Patrick Goss
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1983-03-29
Filing date: 1984-03-23
Publication date: 1984-10-31
Also published as: FR2543711A1; GB8308654D0; GB8407637D0

Abstract

A vehicle instrumentation system 1 has an input 11 that is connected to a processor 13 which supplies output signals to a display 10 and to an output 30. A testing unit 100 supplies signals to the input 11 of the system and receives signals from the output 30 generated by the processor 13 in response to the input signals. The testing unit 100 computes an indication of the output signals that should be produced in response to the input signals supplied to the system, and compares these with the actual output signals of the system. A display 105 and/or printer 106 in the testing unit indicate whether or not the system is functioning correctly. <IMAGE>

Description

SPECIFICATION Vehicle instrumentation systems, testing systems and methods This invention relates to vehicle instrumentation systems, testing systems and methods.

The invention is more particularly, but not exclusively concerned with systems for motor vehicles.

Electronic instrumentation generally have a microprocessor or similar unit that receives input signals from various sensors (such as fluid pressure and level sensors, speed/distance sensors, temperature sensors, warning switches, and so on) and provides output signals to a display. The microprocessor may perform a comparison on some of the input signals and, when the signal indicates an abnormal condition, provide an output causing a warning legend to be revealed on the display. The microprocessor may perform other tasks, such as scaling, conversion to digital form, multiplexing and so on.

Testing of the microprocessor may be carried out prior to installation in the instrumentation system but this does not reveal faults caused by interconnection to the microprocessor or subsequent damage to the microprocessor, such as caused during assembly. It is desirable therefore additionally to test the operation of the completed system and this is usually done by observation of the display, with knowledge of the nature and value of the input signals. Faults in the instrumentation system and in the wiring to the system, or the sensors supplying the input signals, will be revealed by this testing.

The disadvantage of testing the instrumentation system in this way is that it is time consuming and liable to operator error, especially in view of the repetitive nature of the testing.

It is an object of the present invention to provide a vehicle instrumentation system and a testing system that may be used to alleviate the above-mentioned disadvantage.

According to one aspect of the present invention there is provided a vehicle instrumentation system including input means whereby input signals representative of vehicle operation or condition are supplied to said system, display means arranged to display information about vehicle operation or condition, and processor means that is arranged to receive said input signals and supply output signals to said display means to control display of said information, said system including an output that is connected with the processor means, the processor means being arranged to supply the output signals to the output, and the output being adapted for connection to external testing means.

According to another aspect of the present invention there is provided a testing system including a vehicle instrumentation system and input signal generating means, the instrumentation system including display means that is arranged to display information about vehicle operation or condition, and processor means that is arranged to receive the input signals and to supply output signals to the display means to control display of the information, the system including testing means, that is connected with the processor means to receive the output signals, and the testing means being arranged to provide an indication of operation of the processor means.

The testing means may be arranged to supply input signals to the processor means. The testing means may be arranged to provide an indication of the signals that should be produced by the processor means from the input signals, and the testing means being arranged to compare the output signals produced by the processor means with the signals that should be produced by the processor means.

The testing means may include display means and, or alternatively, printing means.

According to a further aspect of the present invention there is provided a method of testing a vehicle instrumentation system of the kind including display means that is arranged to display information about vehicle operation or condition, and processor means that is arranged to receive input signals and to supplying output signals to the display means to control display of the information, including the steps of supplying input signals to the processor means representative of vehicle operation or condition, supplying output signals from the processor means to external testing means, and monitoring operation of the processor means with the testing means.

The external testing means may supply the said input signals to the processor means, and the testing means monitoring operation of the processor means by comparing the output signals from the processor means with a representation generated by the testing means of the output signals that should be produced by the input signals supplied to the processor means.

A vehicle instrumentation system and a testing system for a motor car or other vehicle, in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawing which illustrates schematically a testing system including a vehicle instrumentation system.

The instrumentation system is indicated generally by the numeral 1, and is contained within an outer housing (not shown) adapted for mounting on the dashboard of a motor car or other vehicle. The system 1 has a display panel 10 on which information about the operation and condition of the vehicle is presented to the driver. In this respect, information about speed, distance, time, fuel level, fuel consumption, temperature and so on may be displayed continuously, together with warning legends, when appropriate, to indicate, for example, worn brake linings, low oil level and pressure. The display panel 10 may be formed from solid-state devices such as liquid-crystals or light-emitting diodes. Alternatively, the panel 10 may have conventional discrete moving-pointer instruments.

Input signals to the system 1 are supplied via a connector 11 to an input unit 12. The input unit 12 includes filtering and signal conditioning circuits and supplies output signals to a microprocessor 13. The microprocessor 13 is programmed to process the input signals into a suitable form for driving the display panel 10. It is also programmed to identify when any input signal indicates an abnormal condition of the vehicle (such as worn brake linings or low oil level and pressure) and to provide a suitable output signal to warn of this condition. The output of the microprocessor 13 is supplied in serial data form along line 20 to a display driver unit 21. Other output signals from the microprocessor 13, on lines 22 and 23, provide respectively common clock signals and display driver chip selection.

The display driver unit 21 includes several integrated circuits, or chips, that are each associated with a respective region of the display panel. Signals on line 23 select at any time the appropriate chip for the display region associated with the signals occurring on line 20. The driver unit 21 is connected with the display panel 10 via lines 25 and supplies drive signals to the appropriate region of the display panel (as indicated by the signals on line 23) so that a display is provided representative of the signals on line 20.

The serial data signals and the clock signal on lines 20 and 22 are also supplied to an output connector 30 via an optional buffer unit 31.

Externally of the instrumentation system 1, there is a test unit 100 that is connected to the output connector 30 buy a leads 101 and 102. The test unit includes a computer 103 that receives the output signals from the instrumentation system 1 via a line driver unit 104. A Visual display unit 105 including a terminal is connected with the computer 103, together with a printer 106. In the present embodiment, the test unit 100 is also connected to the input connector 11 via lines 110. The computer 103 is programmed to generate artificially signals representative of the input signals which the system 1 is adopted to receive.

In operation, the input signals supplied to the instrumentation system, from the computer 103 or elsewhere, cause the microprocessor 13 to generate signals on lines 20 and 22 which are supplied to the display driver unit 21 and the computer 103. The computer 103 computes the output signal that should be produced as a result of each of the internally-generated signals supplied to the input of the system 1 and compares these computed output signals with the actual output signals received on lines 101 and 102. An indication of agreement or disagreement of the two sets of signals is given on the visual display unit 105 or onthe printer 106, thereby indicating the nature of any faults.

The input signals to the instrumentation system 1 need not be supplied directly from the computer 103 but could be provided manually by an operator following a predetermined sequence.

Claims

1. Avehicle instrumentation system including input means whereby input signals representative of vehicle operation or condition are supplied to said system, display means arranged to display information about vehicle operation or condition, and processor means that is arranged to receive said input signals and supply output signals to said display means to control display of said information, wherein said system includes an output that is connected with the processor means, wherein the processor means is arranged to supply the output signals to the output, and wherein the output is adapted for connection to external testing means.

2. Atesting system including a vehicle in strumentation -system and input signal generating means, the instrumentation system including display means that is arranged to display information about vehicle operation or condition, and processor means that is arranged to receive the input signals and to supply output signals to the display means to control display of the information, wherein the system includes testing means that is connected with the processor means to receive the output signals, and wherein the testing means is arranged to provide an indication of operation of the processor means.

3. A system according to Claim 2, wherein said testing means is arranged to supply input signals to the processor means.

4. A system according to Claim 2 or 3, wherein the testing means is arranged to provide an indication of the signals that should be produced by the processor means from the input signals, and wherein the testing means is arranged to compare the output signals produced by the processor means with the signals that should be produced by the processor means.

5. A system according to any one of Claims 2 to 4, wherein said testing means includes display means.

6. A system according to any one of Claims 2 to 5, wherein said testing means includes printing means.

7. A vehicle instrumentation substantially as hereinbefore described with reference to the accompanying drawing.

8. Atesting system substantially as herein before described with reference to the accompanying drawing.

9. A method of testing a vehicle instrumentation system of the kind including display means that is arranged to display information about vehicle operation or condition, and processor means that is arranged to receive input signals and to supply output signals to the display means to control display of the information, including the steps of supplying input signals to the processor means representative of vehicle operation or condition, supplying output signals from the processor means to external testing means, and monitoring operation of the processor means-with the testing means.

10. A method according to Claim 9, wherein the external testing means supplies the said input signals to the processor means, and wherein the testing means monitors operation of the processor means by comparing the output signals from the processor means with a representation generated by the testing means of the output signals that should be produced by the input signals supplied to the processor means.

11. A method substantially as hereinbefore described with reference to the accompanying drawing.

12. Any novel feature or combination of features as hereinbefore described.