The Plant Link S.L. Universal User Interface

Author(s):
Juan Guimera - Plant Link, S.L.
John Adams - Plant Link, S.L.

Industry:

Products:

The Challenge:
The problem was to design 8 totally different test systems for a range of widely varying and technically diverse automotive applications, yet make them all familiar and easy to use by a large spectrum of operators, technicians and engineers on three shifts running 24 hours per day. Training was to be kept to an absolute minimum.

The Solution:
The solution was to use facilities and structures already embedded in NI LabWindows to produce a Universal User Interface that is intuitive and ultra easy to use. Every function is accessible by clicking page tabs, self explanatory buttons and menus. The same user interface was employed on all test systems ensuring that they appear almost identical. Knowledge of one tester ensures familiarity with all others.

The test systems were developed for five new manufacturing lines and for field support. The end customer was a highly automated factory of some 600 employees. Eleven testers were built as some locations needed two machines. Each line was for the manufacture of a different automotive module family, including engine control modules (ECMs), vehicle instrument clusters, electronic remote control ignition keys and automobile anti-theft devices. Some applications required vision systems to verify component location and indicator operation. The field support equipment was for car digital radios and for speech recognition modules for driver voice control.

For good test coverage it was essential that each tester was tailor made to the specific module and task. The result was eight tester designs with greatly differing characteristics, ranging from two metre towers to portable briefcase units. Each included either an industrial PC or a lap top (briefcase versions). Different test software packages and drivers were developed for each of the applications and linked to the Plant Link S.L. Universal User Interface, making it common to all test systems. NI TestStand proved ideal for program flow control. Communications facilities and protocols used include: CAN, SCP, ISO9141, Kbus, LIN, TCP/IP, GPIB, USB and Bluetooth. All test data, parameters and test limits (min/max values) are stored externally in text files, Excel tables and data bases. This includes the serial number and a comprehensive set of test results and measurements for every module.

Briefcase Testers and Speech Recognition
The first briefcase tester was for two versions of voice control module. These modules give the driver the ability to operate multiple functions by speech inside higher end BMW cars. The second tester is for the field verification of DAB (Digital Audio Broadcasting) radios, also for BMWs. Due to size restraints all hardware was built out of discrete electronic components, integrated circuits and microprocessors. The testers carry out an extensive set of functional and parametric checks on the module in a similar manner to the large test systems. Special "Engineering Mode" screens in the Universal User Interface are dedicated to audio features such as a variable frequency signal generator and analogue signal level and frequency measurement. In addition there are facilities for working with and testing CAN, Kbus, Bluetooth and fibre optic communication systems. An important tool is the "Flash Memory Analyser." (See later in the article).

Production Test Mode
The fully automatic production test mode is for use during module manufacture. Program start up is triggered by scanning the module label with a bar code reader. The software fills in the "Serial Number" window (see Figure 2) and references the internal data base to load the appropriate test programs for that module type. A full set of functional and parametric tests proceed. Special operations such as calibrations and non volatile memory programming are also completed. If a vision system is included component locations and indicator operation are verified and calibrated. Test results can be downloaded to the factory central database. Clicking the "Report" tab displays all tests performed on one module. Selecting the "Statistics" tab will show the quantity of modules tested, passed and failed. Also displayed is a plot of results. A click of the appropriate box will launch the "Log File Analyser."

Log File Analyser
This is a powerful tool that can show how a single test is performing across a group of modules. It displays graphically the results or measurements of any test for as many modules as required. In Figure-2 pin-1 leakage current can be seen plotted for a sample of 36 modules. It is useful for assessing tester limits and revealing unusual behaviour.

Machine Vision
This important capability is fitted to those test systems where the physical location and orientation of components must be verified. High resolution cameras are used together with NI IMAQ vision software. In the case of the instrument cluster testers, the vision system verifies and calibrates the position, colour and operation of the indicators, display panels and LEDs. The Universal User Interface has a series of screens and facilities to set up and calibrate the equipment.

Engineering Mode
The engineering mode is for test changes and development work. It is password protected so that only those authorised can make alterations. There are multiple engineering screens and facilities. The right click of the mouse reveals a pop up menu of functions available. A test limit can be quickly modified by clicking it. There are excellent program creation, modification and debug tools, including single step, set break points, loop, force pass, skip, etc. Figure-3 shows a right click of the Injector-1 Current routine producing a pop up menu. Selected are: "Run Mode" and "Plot Measured Values."

Virtual Oscilloscope
This plots measured values on the PC screen. Figure-3 shows a diesel engine control module injector current passing through a test system inductor. The peak is approximately 18 amps. A section of the graph can be expanded for greater detail. An NI PCI-5122 100MHz Digitizer card was used for fast sampling. Having traced the current the test system calculates a calibration value for that injector, which is then stored permanently in the module non volatile memory.

Flash Memory Analyser
The Universal User Interface has a set of screens and tools to work on flash and non volatile memories. A fast programming facility can erase or restore all or part of the flash. There are various download and memory contents analysis capabilities. A 1K block can be displayed in Hex alongside addresses from any preset starting point. Data can be shown and worked on in several formats including: ASCII, Hex and FFS.

Author Information:
For more information on this Case Study, contact:
Juan Guimera
Plant Link, S.L.

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