Ethernet Data Acquisition System

Transcription

1 Ethernet Data Acquisition System NI CompactDAQ Measure up to 256 channels of sensor, analog I/O, and digital I/O signals Choose from more than 50 hotswappable I/O modules with integrated signal conditioning Run up to seven hardware-timed measurement I/O tasks simultaneously Stream continuous waveform I/O with patented NI Signal Streaming technology Standard IEEE 802.3ab Gigabit Ethernet communication interface Access four 32-bit advanced generalpurpose counters built into the chassis Simplify setup with zero configuration networking and Web-based configuration BNC digital I/O connections for up to 1 MHz clock import/export and triggers Overview Simple, Complete Ethernet Data Acquisition The NI cdaq-9188 is an 8-slot NI CompactDAQ Gigabit Ethernet chassis designed for remote or distributed sensor and electrical measurements. A single NI CompactDAQ chassis can measure up to 256 channels of sensor signals, analog I/O, digital I/O, and counter/ timers with an Ethernet interface back to a host PC or laptop. By combining more than 50 sensor-specific NI C Series I/O modules with patented NI Signal Streaming technology, the NI CompactDAQ platform delivers high-speed data and ease of use in a flexible, mixed-measurement system. Modules are available for a variety of sensor measurements including thermocouples, RTDs, strain gages, load and pressure transducers, torque cells, accelerometers, flow meters, and microphones. In addition, with NI-DAQmx driver software, you can log data for simple experiments on the benchtop or deploy a distributed test system across the factory floor using NI LabVIEW, ANSI C/C++, Visual Basic.NET, and other programming environments. Application and Technology Mix Analog, Digital, and Sensor Measurements in the Same System Many devices can measure temperature, voltage, or bridge-based sensors, but NI CompactDAQ can integrate all of these measurements and more into a single device that outputs all of the data via the same bus interface. With an NI CompactDAQ system, you can mix multiplexed voltage input signals, simultaneously sampled accelerometers, low-speed thermocouples, and TTL digital I/O all in the same chassis using the same driver, NI-DAQmx. NI CompactDAQ makes programming easier because you use the same driver for all measurements. This solution saves space and simplifies service and support. Figure 1. The NI cdaq-9188 Ethernet chassis can hold up to eight analog I/O, digital I/O, or sensor measurement modules More Than 50 C Series Modules You can choose from more than 50 NI C Series modules for different measurements including thermocouple, voltage, resistance temperature detector (RTD), current, resistance, strain, digital (TTL and other), accelerometers, and microphones. Each C Series module combines sensor connectivity, signal conditioning, and A/D converters into a small 2.8 by 3.5 in. package. Channel counts on the individual modules range from three to 32 channels to accommodate a wide variety of system requirements. With eight slots to fill per chassis, you can tailor each NI CompactDAQ system to your unique application needs. 10

2 Ethernet Data Acquisition System features of NI CompactDAQ help you quickly begin testing because less time is needed to prepare the instrumentation for the rigors of field testing. Figure 2. You can choose from more than 50 NI C Series measurement modules. Long-Distance Ethernet Data Acquisition The convenience and reliability of Ethernet technology are as familiar to most as those of USB. For data acquisition, however, Ethernet offers two advantages when compared to other common PC peripheral buses: long cabling lengths and distributed infrastructure. Ethernet is ideal for taking measurements at distances beyond the 5 m limit of a USB cable. A single CAT 5E cable can reach 100 m before needing a switch or router to carry the signal farther. Furthermore, many IT departments have standardized on Gigabit Ethernet (IEEE 802.3ab) as the backbone for their corporate networks. With NI CompactDAQ, you can take advantage of that existing infrastructure and additional network bandwidth for your remote or distributed measurement applications. One host computer can manage multiple test stations within the same facility or across multiple sites. Four 32-Bit General-Purpose Counters The cdaq-9188 chassis has four 32-bit counters built in. These counters are accessed through an installed hardware-timed digital I/O module (sold separately) such as the NI 9401 or NI Once you have installed the digital module, you can create a counter task in software for operations such as quadrature encoder, period and frequency measurement, or finite pulse train and PWM generation. For some operations, you can access the counters in the cdaq-9188 chassis through the built-in BNC connectors on the chassis. Multiple Timing Engines to Acquire from Different Modules at Different Rates With the cdaq-9188 chassis, you can install a thermocouple module next to an accelerometer measurement module and acquire from both simultaneously at different rates. The cdaq-9188 chassis have multiple analog input timing engines, which means you can group all of your analog input modules in up to three sets of modules. These sets, known as tasks, can all run at different rates because each one has its own timing engine in the chassis back plane. This alleviates the need to decimate or parse lower-speed data from the higherspeed data as you need to do for devices with only one timing engine or ADC. Figure 3. The cdaq-9188 chassis uses a standard 10/100 Ethernet or Gigabit Ethernet connection to communicate with a host PC or laptop. Rugged Design NI CompactDAQ and all C Series modules are constructed from A380 cast aluminum for a rugged system that can withstand operating temperatures from -20 to 55 C, and up to 30 g of shock. NI CompactDAQ was built to be used in the lab but not to necessarily stay there. With a rugged, flexible system such as NI CompactDAQ, you can reconfigure and move a single test system from place to place without having to purchase different equipment for every lab or test stand. C Series modules are equally rugged and designed with spring-loaded latches to lock into place when installed in the chassis. The shock and vibration specifications are all tested on an NI CompactDAQ system with modules installed, so modules do not fall out or come undocked under the specified conditions. The rugged Figure 4. This image shows different AI tasks running at different rates in the same chassis. NI Signal Streaming Technology To take advantage of the 1,000 Mbit/s of bandwidth on a Gigabit Ethernet network, NI CompactDAQ chassis implement a TCP/IP version of the same patented NI Signal Streaming technology on high-performance NI USB data acquisition (DAQ) products. With this technology, high-speed C Series modules, such as the NI 9223, can continuously acquire up to 1 MS/s of simultaneous 16-bit data on each of four channels. Furthermore, multiple NI CompactDAQ chassis can share the same Gigabit Ethernet network for distributed, 11

3 Ethernet Data Acquisition System high-channel-count systems. Using a sophisticated software architecture, NI-DAQmx driver software maintains a double-buffered transfer mechanism between the chassis and host computer capable of sustaining several bidirectional continuous waveforms. At the same time, the driver monitors the state of the network to adjust for unexpected delays or temporary interruptions. All of this is abstracted from the user, so you can focus on the measurement application and not the network. consistent across multiple programming platforms, so you can develop an application for NI CompactDAQ in NI LabVIEW, ANSI C/ C++, C#, or Microsoft Visual Basic.NET. Zero Configuration Networking To make networking technology more accessible to the non-it professional, NI CompactDAQ uses the Zero Configuration Networking (Zeroconf) collection of standards. With Zeroconf technology, you can plug an NI CompactDAQ system directly into your computer or local subnet, and it appears automatically in NI Measurement & Automation Explorer (MAX) without any network setup or configuration. In addition, a new Web configuration interface built into the cdaq-9188 provides the ability to manage your system through a Web browser without installing any software on your host machine. Figure 6. NI-DAQmx driver software abstracts data acquisition bus technology and provides a consistent API across multiple programming languages. National Instruments recommends using the latest version of NI-DAQmx driver software for application development in NI LabVIEW, LabVIEW SignalExpress, LabWindows /CVI, and Measurement Studio software. To obtain the latest version of NI-DAQmx, visit ni.com/support/daq/versions. NI measurement services software speeds up your development with features including the following: A configuration-based interface to create fast and accurate measurements with no programming using the DAQ Assistant Automatic code generation to create your application in LabVIEW; LabWindows/CVI; LabVIEW SignalExpress; and C#, Visual Studio.NET, ANSI C/C++, or Visual Basic using Measurement Studio Multithreaded streaming technology for 1,000 times performance improvements More than 3,000 free software downloads that are available at ni.com/zone to jump-start your project A single programming interface for hundreds of PCI, PXI, USB, Ethernet, and Wi-Fi data acquisition hardware devices Figure 5. With the embedded Web server on the cdaq-9188 chassis, you can remotely configure your NI CompactDAQ system from a Web browser. NI-DAQmx Software Flexibility Recognizing the diversity of measurement applications, NI approaches programmatic data acquisition independent of specific PC bus technologies. You can use the same NI-DAQmx driver software to communicate with NI data acquisition hardware across PCI, PCI Express, PXI, PXI Express, USB, Ethernet, and Wi-Fi. You can use an application developed for an NI CompactDAQ USB system with an NI CompactDAQ Ethernet system without making any changes to your software. Furthermore, the NI-DAQmx API is NI CompactDAQ Ethernet chassis are compatible with the following versions (or later) of NI application software: LabVIEW 8.6, LabWindows/CVI 8.x, and Measurement Studio 8.x. They are also compatible with ANSI C/C++, C#, and Visual Basic.NET. Shipping Kit Contents Every cdaq-9188 shipping kit includes the following: cdaq-9188 eight-slot NI CompactDAQ Gigabit Ethernet chassis 12 VDC power supply (region-specific power cord not included) NI-DAQmx 9.2 (or later) software DVD for Windows 7/Vista/XP LabVIEW SignalExpress LE data-logging software NI cdaq-9188 Quick Start flyer NI screwdriver (flat and Phillips head) 12

4 4-Channel, 1 MS/s/ch C Series Analog Input Modules NI 9222, NI bit, 1 MS/s per channel (NI 9223) 16-bit, 500 ks/s per channel (NI 9222) 60 VDC, channel-to-channel isolation ±10 V range Backshells available for added strain relief Screw-terminal connectivity included in kit Overview The NI 9222 and NI 9223 C Series modules are high-speed, simultaneous modules for use in any NI CompactDAQ or CompactRIO chassis. With a sample rate of up to 1 MS/s and simultaneous analog-to-digital converters (ADCs), these modules are well-suited for applications such as ballistics, impact, and blast wave testing. Comparison Tables Module Range Resolution Simultaneous Sample Rate Isolation NI 9223 ±10 V 16-Bit Yes 1 MS/s/ch 60 VDC, Ch-Ch NI 9222 ±10 V 16-Bit Yes 500 ks/s/ch 60 VDC, Ch-Ch NI 9215 ±10 V 16-Bit Yes 100 ks/s/ch 250 Vrms Ch-Earth (60 V for BNC) NI 9239 ±10 V 24-Bit Yes 50 ks/s/ch 250 Vrms, Ch-Ch NI 9229 ±60 V 24-Bit Yes 50 ks/s/ch 250 Vrms, Ch-Ch NI Vrms 24-Bit Yes 50 ks/s/ch 600 Vrms, Ch-Ch NI A 24-Bit Yes 50 ks/s/ch 250 Vrms, Ch-Ch NI 9219 ±60 V, ±15 V, ±4 V, ±1 V, ±125 mv 24-Bit Yes 100 S/s/ch 250 VAC, Ch-Ch Application and Technology Safety and Accuracy with Channel-to-Channel Isolation Isolation is needed for safe operation around high voltages. With channel-to-channel isolation, your entire system, including the device under test, is protected from harmful voltage spikes up to the isolation rating. In addition to safety, isolation eliminates measurement errors caused by ground loops because the front end of the module is floating. Synchronous Measurements with Multiple ADCs The NI 9222 and NI 9223 use four 16-bit analog-to-digital converters (ADCs) for true simultaneous sampling at up to 1 MS/s per channel. You can synchronize all analog input modules installed in the same chassis to share the same start clock and/or sample clocks. This technology enables higher-channel-count, simultaneous test systems. 13

5 Data Acquisition with Integrated Signal Conditioning for High-Voltage Measurements NI PXIe simultaneously sampled analog input channels 300 Vrms CAT II channel-to-channel isolation 300 V signal inputs with TB-4300B 3,300 Vrms channel-to-earth transient withstand ADC per channel; 250 ks/s/ch sampling rate Programmable gain and lowpass filtering options per channel Multidevice triggering and synchronization via PXI Express Supported by NI-DAQmx driver software Overview The NI PXIe-4300 isolated analog input module provides data acquisition with integrated signal conditioning for high-voltage measurements. It features eight channels with 300 Vrms channel-tochannel isolation and simultaneous sampling up to 250 ks/s per channel. For accurate measurements, the NI PXIe-4300 offers programmable lowpass filters (10 khz, 100 khz, bypass) per channel. You can choose the NI TB-4300 terminal block for 1, 2, 5, and 10 V signal inputs or the TB-4300B for 30, 60, 150, and 300 V signal inputs. The TB-4300 and TB-4300B are front-mounting terminal blocks with screw terminal connectivity. Application and Technology Integrated Signal Conditioning By combining signal conditioning and analog-to-digital converters (ADCs) on the same device, the NI PXIe-4300 isolated analog input module delivers a smaller footprint and higher measurement performance. Integrated signal conditioning also provides simplified cable management and calibration due to fewer components, which drastically reduces the installation and maintenance cost of a high-channel-count measurement system. Safety and Accuracy with Channel-to-Channel Isolation Isolation is needed for safe operation around high voltages. The NI PXIe-4300 has 300 Vrms of continuous channel-to-channel isolation for measurements with differing potentials as well as 3,300 Vrms transient withstand for protection from sudden voltage spikes. In addition to offering increased safety, channel-to-channel isolated systems are more accurate and easier to set up due to the elimination of ground loops. PXI Express Dedicated Data Throughput The SC Express modules are built on the x1 PXI Express bus with dedicated bandwidth per device up to 250 MB/s. Because of the added bandwidth provided by PXI Express, SC Express modules offer simultaneous sampling options using the same channel counts and connectivity as multiplexed devices. Unlike multiplexed devices that reduce sampling rates, you can use simultaneous sampling devices to maintain sampling rates as you expand the number of channels. PXI Platform Advanced Timing and Synchronization PXI Express provides advanced timing and synchronization features, including a 100 MHz differential system clock, differential signaling, and differential star triggers. By using differential clocking and synchronization, PXI Express systems benefit from increased noise immunity for instrumentation clocks and the ability to transmit at higher-frequency rates. The SC Express family leverages PXI Express to deliver tight synchronization between modules in one chassis or multiple chassis. Wide Variety of I/O on the PXI Platform When combined with more than 1500 I/O types in the PXI platform, this module offers the flexibility needed to develop a measurement system that meets your application needs. PXI modules are compatible with the CompactPCI and CompactPCI Express industrial computer standards and offer additional features such as environmental specifications, standardized software, and built-in timing and synchronization. Connectivity The NI PXIe-4300 is designed to be used with the NI TB-4300 and TB-4300B front-mounting terminal blocks. You can choose the TB-4300 for 1, 2, 5, and 10 V signal inputs or the TB-4300B for 30, 14

6 Data Acquisition with Integrated Signal Conditioning for High-Voltage Measurements 60, 150, and 300 V signal inputs. The terminal blocks are hotswappable and automatically recognized in software. This makes troubleshooting easier because you can connect and remove terminal blocks without powering down the PXI measurement system. Each terminal block also includes alignment fins that guide the connector onto the PXI Express module without bent pins. 15

7 Data Acquisition with Integrated Signal Conditioning for Bridge-Based Measurements NI PXIe simultaneously sampled analog input channels 25 ks/s/ch sampling rate; 24-bit ADC per channel; antialias filtering 0.02% of reading typical accuracy Software-selectable excitation voltage per channel (0.625 V to 10 V) Bult-in programmable quarter-, half-, and full-bridge completion per channel Software-selectable shunt calibration options per channel Multidevice triggering and synchronization via PXI Express Supported by NI-DAQmx driver software Overview The NI PXIe-4330 simultaneous bridge input module provides data acquisition with integrated signal conditioning for measuring bridge-based sensors, such as strain gages, load cells, and pressure transducers. It features eight channels with 24-bit analog-to-digital converters (ADCs) per channel and 25 ks/s sampling rate for simultaneous high-speed measurements. To remove noise, each module offers antialiasing and digital filters per channel. Each channel also features an independent programmable to 10 V excitation voltage. Additionally, the NI PXIe-4330 provides remote sensing, internal bridge completion, and shunt calibration options per channel. The NI PXIe-4330 is intended to be used with the NI TB-4330 front-mounting terminal block for screw terminal connectivity. Comparison Tables Module Channels Max Sample Resolution Rate (ks/s/ch) (bits) Bridge Type NI PXIe /4, 1/2, Full NI PXIe /4, 1/2, Full Application and Technology Integrated Signal Conditioning By combining signal conditioning and analog-to-digital converters (ADCs) on the same device, the NI PXIe-4330 bridge input module delivers a smaller footprint and higher measurement performance. Integrated signal conditioning also provides simplified cable management and calibration due to fewer components, which drastically reduces the installation and maintenance cost of a high-channel-count measurement system. Ratiometric Bridge-Based Measurements Many sensors including strain-gages, load cells, pressure sensors, and torque sensors are based on the concept of a Wheatstone bridge. The output of a Wheatstone bridge is measured between the middle nodes of the two voltage dividers. The output voltage of the bridge scales with the excitation voltage. However, the ratio of the bridge output (VCH) and the excitation voltage (VEX) remains fixed over variations in excitation voltage, and it is this unitless ratio (VCH/VEX) that is of interest. To accurately measure the ratiometric output of a bridge based sensor both the bridge output voltage (VCH) and the excitation voltage must be known. The NI PXIe-4330 bridge input module uses circuitry that continuously measures the excitation voltage and applies it as a reference to its analog-to-digital converter (ADC). In this way, variations in the excitation voltage are compensated for, and the module returns data as a ratio of the bridge output voltage and the excitation voltage. This approach removes the measurement s dependence on the stability and accuracy of the excitation voltage. Due to the ratiometric design, measurements with the PXIe-4330 bridge input module will be less susceptible to temperature drift and other variations in the excitation voltage. 16

8 Data Acquisition with Integrated Signal Conditioning for High-Speed Bridge-Based Measurements NI PXIe simultaneously sampled analog input channels ks/s/ch sampling rate; 24-bit ADC per channel; antialias filtering 0.02 percent of reading typical accuracy Software-selectable excitation voltage per channel (0.625 to 10 V) Built-in programmable quarter-, half-, and full-bridge completion per channel Software-selectable shunt calibration options per channel Multidevice triggering and synchronization via PXI Express Supported by NI-DAQmx driver software Overview The NI PXIe-4331 dynamic bridge input module provides data acquisition with integrated signal conditioning for measuring bridge-based sensors, such as strain gages, load cells, and pressure transducers. It features eight channels with 24-bit analog-to-digital converters (ADCs) per channel and ks/s sampling rate for simultaneous high-speed measurements. To remove noise, each module offers antialiasing and digital filters per channel. Each channel also features an independent programmable to 10 V excitation voltage. Additionally, the NI PXIe-4331 provides remote sensing, internal bridge completion, and shunt calibration options per channel. The NI PXIe-4331 is intended to be used with the NI TB-4330 front-mounting terminal block for screw-terminal connectivity. Ratiometric Bridge-Based Measurements Many sensors including strain gages, load cells, pressure sensors, and torque sensors are based on the concept of a Wheatstone bridge. The output of a Wheatstone bridge is measured between the middle nodes of the two voltage dividers. The output voltage of the bridge scales with the excitation voltage. However, the ratio of the bridge output (VCH) and the excitation voltage (VEX) remains fixed over variations in excitation voltage, and it is this unitless ratio (VCH/VEX) that is of interest. To accurately measure the ratiometric output of a bridge-based sensor, both the bridge output voltage (VCH) and the excitation voltage must be known. Comparison Tables Module Channels Max Sample Resolution Bridge Type Simultaneous Rate (ks/s/ch) (bits) NI PXIe /4, 1/2, Full Yes NI PXIe /4, 1/2, Full Yes Application and Technology Integrated Signal Conditioning By combining signal conditioning and analog-to-digital converters (ADCs) on the same device, the NI PXIe-4331 bridge input module delivers a smaller footprint and higher measurement performance. Integrated signal conditioning also provides simplified cable management and calibration due to fewer components, which drastically reduces the installation and maintenance cost of a high-channel-count measurement system. 17

9 Data Acquisition with Integrated Signal Conditioning for Thermocouple Measurements NI PXIe thermocouple input channels; 8 built-in CJC channels 0.30 C typical accuracy for T-type thermocouple 90 S/s/ch sample rate in high-speed mode 24-bit resolution 300 Vrms CAT II channel-to-earth ground safety isolation Autozero channels for offset error compensation; open-thermocouple detection Multidevice triggering and synchronization via PXI Express Supported by NI-DAQmx driver software Overview The NI PXIe-4353 SC Express thermocouple input module provides data acquisition with integrated signal conditioning for temperature measurements. It features 32 channels with three 24-bit analog-todigital converters and operates with high-speed (90 S/s per channel) and high-accuracy (1 S/s per channel) modes. It is designed to be highly accurate with 0.30 C typical accuracy for the module and terminal block. The module has two autozero channels for offset compensation as well as open thermocouple detection to identify disconnected thermocouples. The NI PXIe-4353 is intended to be used with the NI TB-4353 front-mounting isothermal terminal block for screw terminal connectivity. Application and Technology High-Accuracy Thermocouple Measurements With the NI PXIe-4353 SC Express thermocouple module, you can measure temperatures with 0.30 C typical accuracy and 24-bit resolution on 32 channels. The NI TB-4353 isothermal terminal block, which provides powerful cold-junction compensation (CJC), achieves high-accuracy levels. CJC improves your measurement accuracy by offering the temperature at the cold junctions and applying the appropriate correction. The isothermal terminal block minimizes error with a unique design that optimizes thermal conductivity, making it possible for the nearby CJC thermistors to accurately measure the temperature at the thermocouple junctions. The TB-4353 front-mounting terminal block includes eight CJC thermistors that are distributed on the terminal block to closely measure the cold junctions across the terminal block. Integrated Signal Conditioning By combining signal conditioning and analog-to-digital converters (ADCs) on the same device, the NI PXIe-4353 thermocouple input module delivers a smaller footprint and higher measurement performance. Integrated signal conditioning also provides simplified cable management and calibration due to fewer components, which drastically reduces the installation and maintenance cost of a high-channel-count measurement system. PXI Express Dedicated Data Throughput NI SC Express modules are built on the x1 PXI Express bus with dedicated bandwidth per device up to 250 MB/s. Because of the added bandwidth provided by PXI Express, SC Express modules offer simultaneous sampling options using the same channel counts and connectivity as multiplexed devices. Unlike multiplexed devices that reduce sampling rates, you can use simultaneous sampling devices to maintain sampling rates as you expand the number of channels. PXI Platform Advanced Timing and Synchronization PXI Express provides advanced timing and synchronization features, including a 100 MHz differential system clock, differential signaling, and differential star triggers. By using differential clocking and synchronization, PXI Express systems benefit from increased noise immunity for instrumentation clocks and the ability to transmit at higher-frequency rates. SC Express modules take advantage of PXI Express to deliver tight synchronization between modules in one chassis or multiple chassis. Wide Variety of I/O on the PXI Platform When combined with the more than 1,500 I/O types in the PXI platform, this module offers the flexibility needed to develop a measurement system that meets your application needs. PXI modules are compatible with the CompactPCI and CompactPCI Express industrial computer standards and offer additional features such as environmental specifications, standardized software, and built-in timing and synchronization. 18

10 Data Acquisition with Integrated Signal Conditioning for Thermocouple Measurements Connectivity The NI PXIe-4353 is designed to be used with the TB-4353 front-mounting isothermal terminal block. SC Express terminal blocks are hot-swappable and automatically recognized in software. This makes troubleshooting easier because you can connect and remove terminal blocks without powering down the PXI measurement system. Each terminal block also includes alignment fins that guide the connector onto the PXI Express module without bent pins. NI TB-4353 Front-Mounting Isothermal Terminal Block 19

11 Optical Sensor Interrogator NI PXIe optical channels 10 Hz full spectrum scan frequency 1510 to 1590 nm wavelength range Automatic sensor detection and configuration utility for fiber Bragg gratings Compatibility with extrinsic Fabry-Perot, long period grating (LPG), and other optical sensors Rugged carrying case with shoulder strap 1-year warranty Measurement Services Software (included) NI-OSI driver software for LabVIEW (32-bit) NI-OSI Explorer configuration utility Benefits of Optical Sensing Nonconductive, electrically passive, immune to electromagnetic interference Measure over long distances (up to 10 km) without loss of signal accuracy Daisy chain dozens of sensors, including temperature, strain, and pressure, along a single optical fiber Simplified cable management and lightweight fiber No required calibration of the sensor or interrogator (onboard NIST-traceable wavelength reference) Potential for longer fatigue life and faster response than electrical sensors Operating Systems Windows 7/Vista/XP Overview The NI PXIe-4844 optical sensor interrogator is a dual-slot 3U PXI Express data acquisition module for fi ber Bragg grating (FBG) optical sensors. It has four optical channels that are simultaneously sampled at 10 Hz for measurement of FBG strain and temperature sensors. The NI PXIe-4844 features an optical core, which combines a high-power, low- noise swept wavelength laser with fi ber Fabry-Perot tunable fi lter technology from Micron Optics. Each optical channel has an 80 nm wavelength range (1510 to 1590 nm), which can typically scan up to 20 FBG sensors per channel (more than 80 FBG sensors per module, depending on sensor range and sensitivity). You can further extend the maximum number of FBG sensors per module by connecting one or more optical channels to an external optical multiplexer or by adding more NI PXIe-4844 modules in the same PXI chassis. The NI PXIe-4844 can also be integrated into the same chassis as other PXI modules for electrical data acquisition and control. You confi gure the NI PXIe-4844 and FBG sensors in the NI-OSI Explorer, a confi guration manager that scans the optical wavelength range to identify all connected FBG sensors. After you specify the range and scaling equations for each detected FBG, all scans automatically parse the channel data into individual sensor measurements and scale the data into appropriate engineering units. You can export this scaling confi guration for use in the NI-OSI LabVIEW API. Figure 1. Interrogation of an FBG with a broadband light source results in the reflection of a specific wavelength. 20

12 Optical Sensor Interrogator The NI-OSI LabVIEW API has a similar look and feel to NI-DAQmx driver software. Data is returned as an array that you can directly wire to a LabVIEW chart to display scaled data in a value-versustime format. Theory of Operation A fiber Bragg grating (FBG) is an in-fiber structure that reflects specific wavelengths of light while allowing all others to transmit (Figure 1). The reflected wavelength (Bragg wavelength) is a function of both temperature and strain, enabling FBGs to be used as sensors. Each FBG has a unique Bragg wavelength set by the vendor during manufacturing. You can daisy chain FBGs with different nominal Bragg wavelengths within a single optical fiber as long as each FBG occupies a unique wavelength range within the 80 nm optical spectrum of the NI PXIe Benefits of FBG Technology Electrical sensor measurements have several limitations associated with the environment in which they operate: they are prone to noise induced by electromagnetic interference (EMI), they require frequent calibration, they may require external power/excitation, and they are subject to failure when used within harsh environments. Other challenges in distributed civil and geotechnical applications involve the difficulty of installation, the permanent nature of the system, and the large amount of wiring required. Benefits of FBG Optical Sensing Nonconductive, electrically passive and immune to EMI Measurements over long distances (up to 10 km) without loss of signal accuracy Ability to daisy chain dozens of sensors, including temperature, strain, and pressure, along a single optical fiber No required calibration of the sensor or interrogator with NIST-traceable wavelength reference Measure Anywhere Ability to mix and match different measurement types on the same sensor array Simplified cable management and lightweight fiber Potential for faster response than thermocouples and longer fatigue life than foil strain gages Potential for immunity to lightning, high voltages, and corrosion depending on sensor packaging Ability to embed sensors in composite materials Advantages of the NI Optical Sensor Interrogator Traditional optical measurement devices provide fixed software functionality and a fixed user interface. This lack of flexibility limits the system s ability to meet many structural test and monitoring application needs. In addition, traditional optical sensing instruments are not designed for easy integration with electrical measurements or control systems, which is often required in real-world structural and environmental measurements. The NI optical sensor interrogator (OSI) offers seamless integration with NI LabVIEW, a graphical development environment for customizable software and easy UI development. The NI PXIe-4844 is also based on the PXI platform, providing modular I/O for easy integration with a wide variety of PXI and PXI Express devices, including conventional thermocouple, strain, and vibration devices as well as analog and digital outputs for control requirements. PXI Express High-performance PCI Express bus Advanced differential timing and triggering backplane Integration with electrical I/O with more than 1,500 PXI modules Modular I/O for easy expansion Easy to Use NI-OSI Explorer utility for automatic sensor detection and simplified sensor configuration for easy scaling to physical units NI-OSI driver software with easy-to-use LabVIEW API including common optical measurement functions Tight integration with LabVIEW for data analysis, viewing, and logging Application Examples Civionics distributed measurements over long distances, including bridges, buildings, and other civil structures Energy monitoring wind turbine blades, pipelines, nuclear reactors, offshore platforms, power generators Marine Vessel and Platforms cargo containers, deck, mast, or any other corrosion-prone structure Aerospace airframe, composite structure, fuel tank, wind tunnels Research big physics, material testing, vehicle prototyping 21

13 Optical Sensor Interrogator Specifications Specifications listed below are typical at 25 ºC unless otherwise noted. Optical Properties Number of optical channels... 4, simultaneous Scan frequency Hz ± 0.1 Hz Wavelength range to 1590 nm Wavelength accuracy... 1 pm Wavelength stability (10 to 55 C)... 1 pm Wavelength repeatability... 1 pm Optical dynamic range db Optical connectors... LC/APC Environmental Operating Temperature... 0 to 55 C Humidity to 90%, noncondensing Storage Temperature to 70 C Humidity... 5 to 95% noncondensing Altitude Meters at 25 C... 2,000 m Bus Interface Form factor... x4 PXI Express, 2-slot module Calibration Not required... Internal NIST-traceable reference artifact 22

14 High Performance USB Multifunction X Series DAQ Device USB X Series NI X Series devices are the most advanced multifunction data acquisition (DAQ) devices ever designed by National Instruments. Designed for performance, they feature enhancements to address the needs of the most demanding test and measurement applications. X Series devices for USB include up to 32 analog inputs, four analog outputs, 48 digital I/O lines, and four counters, with sampling rates from 500 ks/s to 2 MS/s Advanced Technologies on USB To extend what is possible with a single multifunction data acquisition device, USB X Series devices include two key technologies: NI-STC3 timing and synchronization technology and NI Signal Streaming technology. NI-STC3 Technology Coordination of the timing and triggering of the analog, digital, and counter subsystems. Four 32-bit counters for event counting, pulse generation (PWM), frequency and encoder measurements, and more. 100 MHz timebase for generating sample clocks and five times better resolution than previous devices. NI Signal Streaming Patented technology that ensures high-speed bi-directional data transfer over USB Message-based instructions and device-side intelligence Concurrent analog, digital, and counter operations Product Family Specifications To extend what is possible with a single multifunction data acquisition device, USB X Series devices include two key technologies: NI-STC3 timing and synchronization technology and NI Signal Streaming technology. NI Product 16-Bit Analog Inputs Max AI Sampling Rate (One Ch.) Aggregate AI Throughput (All Ch.) 16-Bit Analog Outputs Digital I/O NI USB ks/s 500 KS/s 2 24 NI USB ks/s 500 KS/s 4 48 NI USB MS/s 1 MS/s 2 24 NI USB MS/s 1 MS/s 4 48 NI USB MS/s 1 MS/s 2 24 NI USB MS/s 1 MS/s 4 48 NI USB Simultaneous 1.25 MS/s/ch 10 MS/s 2 24 NI USB Simultaneous 2 MS/s/ch 16 MS/s 2 24 Table 1. Compare key specifications of USB X Series products. USB X Series Features Improved Mechanical Enclosure USB X Series devices introduce a redesigned, extruded aluminum enclosure with an easy-access magnetic lid. This lid keeps signal wiring secured and shielded and can be opened easily when needed. The underside of the lid has a device-specific pinout label so you can quickly determine the corresponding screw terminals for a given channel. Figure 1. USB X Series devices feature a completely redesigned mechanical enclosure, and include an easy-access lid with device-specific pinouts. The enclosure also includes a lockable USB port to prevent accidental removal during operation. You can separately purchase DIN-rail and wall-mount accessories for USB X Series. Simultaneous Sampling USB DAQ By taking advantage of NI Signal Streaming technology, NI is able to make simultaneous sampling available in multifunction USB devices for the first time ever, with the USB-6356 and USB These two devices can sample at 1.25 MS/s and 2 MS/s on each of eight analog inputs and include 32 or 64 MS of onboard memory. The high sampling rates on all channels make these devices ideal for portable ultrasonic test and transient recording applications. Long-term, continuous operation of these devices will be dependent on the host PC, sampling rate, and channel count. 23

15 High Performance USB Multifunction X Series DAQ Device Simultaneous sampling devices also preserve the phase relationship of your input signals, because the multiple-adc architecture eliminates the need to multiplex among input signals. Flexible Software One of the biggest benefits of using a PC-based data acquisition device is that you can use software to fully customize the functionality of your measurement system to meet your exact application needs. You interact with a USB X Series device with the flexible, comprehensive NI-DAQmx driver software. All National Instruments DAQ devices use this driver, which means that you can easily reuse existing code in a new USB X Series application. You can call into the NI-DAQmx driver software from a variety of programming environments, including NI LabVIEW, C/C++, Microsoft Visual Basic.NET, and C#.NET. To help you quickly get started, NI-DAQmx includes a dialogue-based wizard, the NI DAQ Assistant, which you can use to acquire and generate analog data with no programming. For additional user control and flexibility, NI-DAQmx also provides a comprehensive API with functions and property nodes. 24