PXI Express DAQ modules with integrated signal conditioning

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PXI Express DAQ modules with integrated signal conditioningNational Instruments is introducing the new NI SC Express data acquisition (DAQ) modules with integrated signal conditioning for scalable, high-performance measurements on PXI Express. The NI SC Express family delivers increased accuracy, high data throughput and best-in-class synchronisation for measuring strain gauges, bridge-based transducers, thermocouples and high-voltage analogue inputs. PXI Express provides 250MB/s of dedicated bandwidth for each SC Express module in the chassis, which helps engineers increase channel count without compromising sampling rates or data throughput. With a smaller footprint, simplified cable management and new software features for automatic synchronisation, the SC Express modules are said to make it easy for engineers to set up and program high-channel-count sensor measurement systems.

The NI PXIe-4330 24-bit simultaneous bridge input module offers 0.02 per cent accuracy and a sample rate of 25kS/s per channel for high-performance strain, load, force and torque measurements. The bridge input module achieves high accuracy with a ratiometric design in which the ADC references the excitation voltage. This approach removes the measurement's dependence on the stability and accuracy of the excitation voltage. In addition, NI's delta-sigma ADCs provide both excellent AC performance as well as DC accuracy, while traditional delta-sigma ADCs only offer AC performance.

Automatic synchronisation

According to NI, the new NI PXIe-4330 bridge input module can perform quarter, half and full bridge-based measurements with automatic synchronisation features. The included driver software ensures tight synchronisation across multiple modules and chassis with inter-channel skews as low as 5ppb. The eight-channel bridge input module can scale to a 136-channel system in a single chassis and thousands of channels when synchronising across multiple chassis. The high-accuracy, simultaneity and synchronisation features make the NI PXIe-4330 module particularly suitable for high-channel-count structural test applications, such as wind tunnels, bridge monitoring and crash tests.

With the NI PXIe-4353 thermocouple module, engineers can measure temperatures with 0.30degC accuracy on 32 channels. The isothermal terminal block minimises error with a special design that optimises thermal conductivity, making it possible for the nearby cold-junction compensation (CJC) thermistors to measure accurately at the thermocouple junctions. The 32-channel thermocouple module can scale to a 544-channel system in a single chassis and thousands of channels when synchronising across multiple chassis. The increased accuracy and scalable platform make the NI PXIe-4353 module is suitable for precision measurements from a single channel to large systems for applications such as fuel cell testing and monitoring thermal chambers.

Measure voltages up to 300V

Another new module, the NI PXIe-4300 high-voltage isolated analogue input module, is the first analogue input module from National Instruments that can measure up to 300V with simultaneous sampling. With a 16-bit ADC per channel and a 250kS/s per channel sampling rate, the NI PXIe-4300 module can stream 4MB/s per module and 68MB/s in a single chassis. This eight-channel analogue input module can scale to a 136-channel system in a single chassis and thousands of channels when synchronising across multiple chassis. The ability to measure 300V with CAT II channel-to-channel isolation makes the NI PXIe-4300 module useful for automotive testing, such as fuel cell and battery tests.

The new SC Express modules include NI-DAQmx driver software and support for multi-device tasks, which is a new feature of NI-DAQmx that helps engineers synchronise multiple modules more easily. The same code that acquires data from one module can synchronise up to 17 modules in a chassis. The modules work with a variety of NI hardware including NI X Series, dynamic signal acquisition (DSA) and NI SCXI products, and more than 1500 types of I/O available on the PXI platform. The new modules also integrate with NI software including NI LabVIEW and the LabVIEW Real-Time Module, NI-Sync and NI DIAdem.

Go to to learn more about achieving higher measurement performance with the SC Express family.

26 May 2010

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