Customer SolutionsSymtx Tests Military Combat Training Systems with NI TestStand, LabWindows/CVI, and PXI
Author(s):Corry Johnson, Symtx Functional Test Solutions
Industry:Government/Defense
Product:LabWindows/CVI, Modular Instruments, NI TestStand, PXI/CompactPCI
The Challenge:Developing a high-volume production test system for laser tag assemblies used in military training systems.
The Solution:Using PXI, LabWindows/CVI, and NI TestStand to develop a complex optical and wireless RF test solution.
High-volume test systems are notoriously difficult to design. A Symtx customer approached us to develop just such a system for high-volume production test assemblies used in military personnel training. A Revolutionary Optical and Wireless Test Process This project presented a significant challenge for us because the customer needed the same test station to measure and adjust optical sensitivity, test wireless RF link performance, and verify user display operation. The customer also required a similar station to simultaneously provide shock profiles to 200 g forces and align unit under test optics to within 0.01 degrees. Designing a mixed-technology product requiring precision measurements for each of these areas made this design particularly complicated. The training systems consist of a vest and associated headband with an array of optical detectors and a corresponding rifle-mounted laser transmitter. We integrated these using a wireless RF link. When the soldier fires the weapon (using blanks), the system accurately simulates a kill or near-miss using optical pulses calibrated for the actual weapon range. We had to test and align each assembly to ensure consistent performance in the field. Vest measurements include optical signal decoding and sensitivity, wireless RF link communication, battery current draw, user control and display functionality, speaker output, and shield/connector contact integrity. PXI-Based System for Transient Signal Measurement For our solution, we used a rugged, high-throughput, low-cost PXI-based system that includes a National Instruments PXI-4070 FlexDMM, which is a combination 6½-digit digital multimeter (DMM) and high-speed digitizer, to measure the static and transient signals from the various station sensors. The PXI system also acquires images from an IEEE 1394 (FireWire) and analog camera for display verification and character recognition. GPIB-controlled instruments augment the PXI system for optical signal generation, switching, and power measurement. RF Generation and Measurement For RF generation and measurement, the system includes a custom RF serial interface module (SIM) printed wire board mounted in each fixture. Data transmission occurs across an RS232 interface in the PXI chassis. Finally, the test station includes a GPIB-controlled reference laser to generate the optical signals that simulate the optical pulses the laser transmitter generates during normal operation. We modulated this laser using a custom FPGA (controlled via digital I/O lines from the PXI chassis) to generate the required optical codes. We used NI TestStand and LabWindows/CVI software to control the system. NI TestStand provided us with an open architecture sequencing framework so we could integrate and automate our LabWindows/CVI test modules. Our programmers could then quickly and easily develop a test program that is both powerful and flexible. A Single System Based on NI Software and PXI Hardware for High-Volume Production Test High-volume production testing of a laser tag system presents technical challenges across multiple disciplines. However, using commercial off-the-shelf technology such as PXI, NI TestStand, and LabWindows/CVI software, along with careful attention to effective design practices, we achieved this within a single, integrated system. With this solution, we were able to develop a complex optical and wireless RF test system. For more information, contact: Trevoris Morgan, Marketing Manager Symtx Functional Test Solutions Tel: (512) 328-7799, ext. 222 Fax: (512) 328-7778 E-mail: tmorgan@symTX.com Customers interested in this application may also be interested in these NI products: |
