When accuracy really counts, you should make four-wire resistance measurements. Sometimes referred to as the Kelvin method, the four-wire resistance method is often used in automated test applications where long cable lengths, numerous connections, or switches exist between the digital multimeter (DMM) and the device under test (DUT).
Testing that requires the use of strain gages often consume large amounts of resources and effort to prepare for. One way to reduce the amount of time and energy spent configuring a test is to use sensors that support the Transducer Electronic Data Sheet (TEDS) interface. Many VTI measurement instruments support TEDS sensors including the EX1629 48-channel high-performance strain gage measurement instrument, EX1403 16-channel bridge/strain gage instrument, and the RX1024 24-channel bridge/strain gage instrument.
Although thermocouples are the most commonly used temperature sensor in test applications, a close second is the resistance-temperature detector, or RTD. RTDs operate on the principle that the resistivity of a metal is proportional to its temperature. The higher the temperature, the higher the resistivity.
For many test applications, measuring the temperature is a necessity. For example, when testing an aircraft engine, you may need to measure manifold temperature or the exhaust gas temperature. To help you take those measurements, VTI Instruments offers a number of options, including the EX1000A series of precision voltage measurement instruments and the RX1032 rugged thermocouple measurement system.
Thermocouples are arguably the most common type of temperature sensor, although you can also use resistance temperature detectors (RTDs), or thermistors. The EX1000A series supports all three types of sensors, while the RX1032 supports only thermocouples.
When performing functional tests, keeping test times as short as possible is often a critical requirement. Time is money, after all. One way to reduce test times is to reduce the latency in setting up signal switch paths, stimulus devices, and measurements. These can all have a significant impact on the overall time it takes to complete a full functional test of a particular DUT.
VTI Instruments' new RX0424 IEPE/Voltage Instrument is a cost-effective new device that is ideal for measuring acceleration forces and sensing static and dynamic movement or vibrations. Fully-integrated IEPE current excitation and tachometer input channels further enhance the instrument’s utility and functionality.
The automotive market is a highly competitive and complex business. In order to be competitive, vehicles must not only offer comfort and top-notch features at a cost-effective price but also ensure passenger safety. Long before any new model goes into mass production, a long series of sophisticated tests and validations are required at various stages to ensure that the vehicle meets all governmental standards and company performance standards.
Vehicles are often operated under test conditions for weeks or months, which requires logging and archiving massive amounts of data. In addition, in-vehicle tests often require the use of portable test systems, which are ideally compact, rugged, light in weight and free standing. Given the limited space within the vehicle, they typically must operate wirelessly with no connection to a computer. These in-vehicle datalogging systems must be compatible with a wide array of sensors.
A jet engine is the very definition of “mission-critical.” A critical failure could cause a serious accident that endangers hundreds of lives. To prevent this from happening, manufacturers perform extensive testing on jet engine components, systems, and manufacturing processes.
Jet engine tests involve subjecting the unit under test to extreme temperatures, jets of water, simulated hail, severe vibration, and other harsh conditions. Sometimes test engineers even slam chicken carcasses against engines to simulate bird strikes. These tests can be very costly and take years to develop. Engineers must measure many different parameters during these tests, including temperature, flow, pressure, rotation, strain, and vibration.
Data acquisition systems are at the core of many automatic test systems and industrial control systems. They make various types of physical measurements, such as temperature, pressure, flow, strain, position, and speed, using electronic equipment. The data collected is usually sent to a computer for analysis and display.
Interchangeable Virtual Instruments (IVI) is a standard for instrumentation drivers that is designed to reduce the time and effort needed to integrate measurement devices into new or existing systems. It does this by providing a standard application programming interface (API) that defines common measurement functions. This is, in turn, provided by a standard set of shared components that must be used by all compliant drivers and ancillary software. These components provide services to drivers and driver clients that need to be common to all drivers.
