Dipl.-Ing. Markus Solbach - NOFFZ ComputerTechnik GmbH
Marc Abels - NOFFZ ComputerTechnik GmbH
Dipl.-Ing. Sergej Dirks - NOFFZ ComputerTechnik GmbH
Enrique Gutierrez - Peiker Acustic GmbH & Co.KG
Starting in 2014, the European Union requires all new vehicles to be equipped with an “eCall” emergency call system, which can automatically call the European emergency number 112 in case of an accident. The system also simultaneously transmits the vehicle’s GPS location information to initiate and perform rescue operations more quickly and efficiently. Peiker acustic GmbH & Co. KG in Friedrichsdorf, Germany has successfully manufactured microphones, hands-free systems, multimedia systems, and telephone modules for the automobile industry for many years. The company’s extensive experience in the area of mobile communication technology made it the go-to manufacturer for mass production of these eCall modules. Thus, peiker needed a run-in screening tester capable of testing up to 28 eCall modules in one climatic chamber in parallel. The company also needed comprehensive module management for the various modules, which are equipped with different bonding and board layouts depending on the vehicle manufacture
We needed the system to be able to perform a complete performance check on the devices under test (DUTs). We also needed to design and implement it based on the NOFFZ UTP 9065 test system. We required all of the testing devices to switch on the DUTs for testing and evaluation purposes. We used National Instruments hardware components, such as data acquisition cards and power supply devices, for integration within the testing device. Furthermore, we wanted to use NI PXI hardware in an appropriate chassis as much as possible. We needed the UTP 9065 to provide ideal communication between the test item and the testing device and maintain complete accessibility to the customer’s data bank and the iTAC traceability system by peiker to manage serial numbers and communicate test results.
Definition of the Problem
We required a solid climatic chamber test system for the run-in and screening test of a large volume of in-vehicle eCall modules. We wanted the test system to perform a parallel screening test with 28 test items for a temperature range between −40° C and 85° C. Aside from the connection with the customer data bank and the iTAC system, the test item should also provide extensive management of variables for individual contact and test item measuring and be able to transfer a test-item specific temperature curve for the climatic chamber. We needed to keep the lead time as short as possible, so the testing device should perform as many measurements as possible on all 28 test items. The system must perform, among others, the following procedural steps and testing stages: quiescent current measurement, waking up via USB and over a diagnostic controller area network (CAN-DIAG), activation of the testing mode, inquiry of hardware and software status, and over-charge as well as low-voltage operation. As part of the project we needed to use NI LabVIEW software and NI TestStand software to design separate code modules for the CAN bus, the control of the digital I/O and the climatic chamber, the parallel current measurement, and to implement further testing requirements.
Peiker already standardized on the NOFFZ UTP Test Execution Frontend (TEF) for batch processing the DUTs, which was the basis for implementing the testing procedure in NI TestStand. We will individually adjust the corresponding processing model to the requirements of the eCall modules under test to ensure an optimal and parallel process with minimal lead time. The screening test in the climatic chamber depends on temperature, so warm-up and cool-down periods prolongue the resulting testing, and is not subject to further increases due to the testing of the test item.
The following timetable applies to the testing:
- The test starts at around 20 °C ambient temperature and begins with an ~25 minute cool-down phase to −40 °C.
- The test items remain at this temperature for 30 minutes and are measured before the 40 minute warm-up phase up to +85 °C starts.
- Once the temperature is reached, the test items need to be operated for 60 minutes and measured once more before they are cooled to 20 °C within 30 minutes so they can be removed from the climatic chamber without the build up of condensed water.
Therefore, we can determine a lead time of 185 minutes with the help of the temperature curve. During the testing process, the iTAC System pretdetermines and assigns the DUT with a serial number. After the conclusion of the test, the test results are immediately documented in the iTAC data bank.
Challenges and Solutions
During the development of this test system, we faced several challenges due to the high number of test items required and the resulting high level of parallelization. Directly connected to this, we still needed to meet the necessary lead time optimization despite the long cycle times due to the warm-up and cool-down phases. The flawless communication with the customer data bank and the manufacturing execution system, including the version and serial number management, posed another challenge. Peiker was supposed to achieve the connection with existing software structures, and HPVee was supposed to transfer the existing software modules into the LabVIEW and NI TestStand framework.
We finally managed the large number of test items using powerful NI PXI hardware that can provide up to 32 serial interfaces and up to 96 I/O channels. We can now process various test stages in parallel, such as the switiching on of the test items, the building up of the communication, and the measuring of the quiescent current. We only sequentially completed the review of the GSM Last Functionality for all test items. We optimized and expanded the NOFFZ TEF with NI TestStand for the display of status updates of all 28 simultaneously performed tests. We met the request for the lowest possible lead time by optimizing the implementation of the parallelization with the help of powerful hardware and consistent modularization on the software side (Figure 1).
Based on the customer’s iTAC libraries, we successfully implemented a connection with the traceability system databank, thus allowing for the management and assignment of serial numbers as well as the direct transfer of test reports to the data bank.
Software and Hardware Used
We implemented the parallel testing procedure of the batch process, including the version management, with NI TestStand. We implemented the individual test steps modularly with LabVIEW and subsequently integrated in NI TestStand. Other measuring devices, power supplies, and other hardware components used in the tester (Figure 2) include:
- NI PXI-1045 18-slot chassis
- MXI interface to record all measuring and card modules via interprocess communication
- PXI 100 × single-pole, single-throw electro-magnetic relais
- NI PXI-6225 data acuisition board for parallel activation of the USB supply voltage for the 28 DUTs
- NI PXI-4065 digital multimeter for the parallel differential recording of the quiescent currents
- NI PXI-8513/2 NI-XNET CAN interface to measure the CAN bus level and the USB shield resistance
- NI PXI-2576 multiplexer to control the CAN-EPT and CAN-DIAG
- NI PXI-2547 high-frequency multiplexer to control the debugging interface in parralel
- NI PCI-GPIB to connect a test item with a 100 k charge
- NI PXI-6509 digital I/O module to control the power supplies
- NI PXI-PCI8360 MXI-Express controller for system and adapater control
- N5747A DC system power supply from Agilent to control the NI PXI chassis through an IPC
- N5745A DC system power supply from Agilent for the parallel supply of the 28 test items
We performed the parallel USB supply of the 28 test items with the hubs and USB switch cards. We used the climate chamber with parameter settings from NI TestStand and direct access to performance in the range of −40° C to 85° C within the climate chamber to control temperature.
Conclusion and Future Outlook
After successfully designing a solid, flexible run-in and screening system for eCall modules based on the NOFFZ UTP 9065 concept that also offered extensive variant management, as well as the connection to the customer data bank and the iTAC system, we are planning more test systems for the near future (Figure 3). Aside from changes in the usability of those systems actual running projects, we used the NI vector signal transceiver hardware to power nonsignalling tests for call setups in a time-efficient manner and further reduce the lead time of the test items. A fully functional multidevice test of eCall phone module devices is now possible under several temperature conditions.
We could easily adjust the test processes for new variants because of the high level of modularization and optimization for the software development as well as the standardized variant management with the surface NOFFZ UTP TEF.
Dipl.-Ing. Markus Solbach
NOFFZ ComputerTechnik GmbH
Tel: +49 (0)2151 99878-80
Fax: +49 (0)2151 99878-88