Customer SolutionsNI LabVIEW and TEDS Streamline Automotive R&D
Author(s):Peter Blume, Bloomy Controls Inc.; Lesley Cannon, Bloomy Controls Inc.; Robert Greene, NSK Steering Systems America Inc.
Industry:Automotive
Product:Data Acquisition, LabVIEW
The Challenge:Improving the efficiency of an automotive R&D test laboratory.
The Solution:Using National Instruments LabVIEW and virtual transducer electronic data sheets (TEDS) for quick interchangeability, configuration, and calibration of transducers used in testing.
Steering Column Test NSK Steering Systems America Inc. (NSK) manufactures steering systems for vehicle and cockpit manufacturers. Its R&D laboratory in To accommodate the different transducers, we developed separate data acquisition software applications for each transducer/test combination. An engineer manually edited transducer range and calibration data hard coded within the software. This mass duplication, distribution, and editing of source code created reliability and repeatability issues. Additionally, user interfaces became inconsistent, increasing the time required to train operators. To simplify the configuration of transducers and tests, and streamline the maintenance and control of the data acquisition software, we contracted National Instruments Alliance Partner Bloomy Controls. Using LabVIEW and IEEE 1451.4 standard format and TEDS, we created applications that easily support transducer interchangeability and provide reliable storage of calibration data. Hardware System Design We began by replacing several legacy data acquisition boards in the existing NSK system with one NI M Series PCI-6221 data acquisition board, reducing the cost and complexity of the system. The PCI-6221 board performs both analog voltage and quadrature encoder measurements. Analog transducer conditioning is accomplished using the legacy 5B signal conditioning in an NI SC-2311 carrier. By simply treating each module channel as high level ±5 VDC analog input signals, the new application can support the previous signal conditioning modules. The system takes encoder measurements by wiring to the programmable function input (PFI) lines of the NI PCI-6211 via the NI SC-2311. The PFI lines and analog channels are configured for each application. The PC acquires all test data using LabVIEW, NI-DAQmx, and the PCI-6221 board. Virtual TEDS files support the NSK legacy transducers that are not IEEE 1451.4 standard compliant. We wired the transducers into 5B signal conditioning modules, and the high-level voltage output sensor template (IEEE Standard template 30) generates the Virtual TEDS files. Calibration data is stored within the TEDS files using the calibration curve template (IEEE Standard template 41). To save new Virtual TEDS files, we developed a simple application for the operator to enter basic transducer data used to populate the IEEE templates. The Virtual TEDS files greatly simplify configuring channels in NI-DAQmx. Only the file path to the Virtual TEDS file is required to configure all aspects of each channel. This includes transducer type, engineering units, and physical and electrical range. Once configured, the operator creates a TEDS AI Voltage task for that channel. NI-DAQmx transparently performs the appropriate engineering unit conversion. Calibration data is conveniently stored in the Virtual TEDS files and is automatically applied to the transducer measurements. Several tests required the use of an encoder. Because TEDS does not currently support encoders, we used Windows config files to store the encoder configuration data. TEDS simplified developing applications to test the UUT. NSK replaced multiple applications with one LabVIEW application that can conduct all load tests, regardless of UUT design, transducer range, or manufacturer. Several different torque test applications were likewise replaced with one streamlined LabVIEW application. NSK can add new transducers d to either application by simply configuring new TEDS files. System Operation The load and torque tests are separated into load and torque applications, each of which functions as a virtual chart recorder that plots load or torque against angular or linear deflection of the UUT. The operator chooses which transducers to use for any given test from a list that is generated by scanning the TEDS file folder for available TEDS files. Specifically, the Select Sensor.vi prompts the user to select the transducers and the PCI-6221 channels. The software reads the TEDS files from a directory and populates the device control with the corresponding transducer names. A subset of data is read from the TEDS files and displayed next to the selected transducer. The operator zeroes each sensor prior to each test by clicking the zero button from the main graphical user interface. This establishes a reference point for all subsequent measurements. The R&D laboratory environment contains a considerable amount of electromagnetic signal noise and interference. The operator may optionally configure a filter and averaging routine to minimize the effects of the interference on the measurements. Pressing the pen down button begins data recording. The operator applies a load to the UUT as data records to file and displays on a live graph indicator. The data generated during testing can be printed and saved to file, or cleared without saving, by clicking the print, save data, and clear buttons, respectively. Additionally, the operator can load and review previous test data. Saving Time, Increasing Efficiency We replaced dozens of applications in our R&D laboratory with two flexible, easy-to-use LabVIEW applications. Operators can configure new transducers for their ever changing test requirements without editing the source code. In addition, operators can interchange or replace transducers as test requirements demand or hardware failure necessitates. Each test station maintains a folder of Virtual TEDS files so that transducers can be interchanged between stations and accurately calibrated at the stations where they are applied. We saved time by not needing to develop new software for every new test requirement, and test stations are now easily replicated. Consistent user interfaces reduce operator error and training requirements. Overall efficiency in the R&D laboratory has increased with less time spent searching for the correct version of an application or trying to determine the proper calibration data. A National Instruments Alliance Partner is a business entity independent from NI and has no agency, partnership, or joint-venture relationship with NI. For more information, contact: Peter Blume President/Engineering Director Bloomy Controls Inc. Tel: (860) 298-9925 Fax: (860) 298-9535 E-mail: peter.blume@bloomy.com |
