National Instruments transforms the way engineers and scientists around the world design, prototype, and deploy systems for test, control, and embedded design applications. Using NI open graphical programming software LabView and modular hardware, customers at more than 25,000 companies simplify development, increase productivity, and dramatically reduce time to market. From testing next-generation gaming systems to creating breakthrough medical devices, see how NI technology is used to continuously develop innovative technologies that impact millions of people.
= PCI eXtensions for Instrumentation
Developed in 1997 and launched in 1998, PXI was introduced as an open industry standard to meet the increasing demands of complex instrumentation systems. Today, PXI is governed by the PXI Systems Alliance (PXISA), a group of more than 65 companies chartered to promote the PXI standard, ensure interoperability, and maintain the PXI specification. For more information on the PXISA, including the PXI specification, refer to the PXISA Web site atwww.pxisa.org.
Natioanal Instrumnents named PXI a rugged PC-based platform for measurement and automation systems.
PXI combines PCI electrical-bus features with the modular, Eurocard packaging of CompactPCI and then adds specialized synchronization buses and key software features. PXI is both a high-performance and low-cost deployment platform for applications such as manufacturing test, military and aerospace, machine monitoring, automotive, and industrial test.
Integral parts of PXI
As defined by the PXI Hardware Specification, all PXI chassis contain a system controller slot located in the leftmost slot of the chassis (slot 1).
Controller options include remote control from a standard desktop PC or a high-performance embedded control with either a Microsoft operating system (such as Windows 2000/XP/7) or a Real-Time operating system (such as LabVIEW Real-Time).
NI PXI System Controllers
On the PXI platform, NI offers 3 options for interfacing with CPU:embedded controller, remote controller or rack-mount controller.
Embedded controllers bring the processor physically into the PXI chassis, creating a complete system. These controllers run both standard (Windows, Linux) and real-time operating systems and feature integrated peripherals like ethernet, USB and serial ports.
With PXI remote controllers, you can control PXI systems with standard desktop and laptop PCs. The links are high-throughput and software-transparent. PC control of PXI enables use the latest desktops, servers, and workstations for applications that require the highest-performance processor, high-speed or long-duration streaming to disk, etc. Fiber-optic cabling options are available for long distances (up to 200 m) and electric isolation. PXI remote controllers can also be used to build multichassis PXI systems.
Rack-mount controllers are a high-performance computing option in a convenient 1U form factor. Additionally, these controllers support RAID configurations, for applications demanding high speed data streaming to disk.
Embedded PXI Chassis types
The chassis provides the rugged and modular packaging for the system. Chassis, ranging in size from 4-slots to 26-slots, are available for all different types of applications – portable, benchtop, and rack mount. Chassis are available with all 3U slots, all 6U slots, or a combination of 3U and 6U slots, and chassis are also available with special features such as DC power supplies and integrated signal conditioning.
The PXI Express Backplane
The chassis contains the high-performance PXI backplane, which includes the PCI bus and timing and triggering buses. These timing and triggering buses enable users to develop systems for applications requiring precise synchronization. PXI is built on the modular and scalable CompactPCI specification and the high-speed PCI bus architecture.
Modular PC-Based Architecture Provides Flexible Functionality. PXI provides a platform with a breadth of functionality available, including analog and digital I/O, high-speed instrumentation, vision, motion, and various interfaces. More than 1,500 PXI Products from More than 70 Vendors.
PXI Timing and Synchronization Features
NI provides timing and synchronization solutions for both PXI and PXI Express chassis. As the latest evolution of the PXI platform, PXI Express is designed to deliver a higher degree of synchronization to measurement I/O devices than PXI-1 while remaining backward compatible. PXI Express maintains the 10 MHz backplane clock as well as the single-ended PXI trigger bus and length-matched PXI star trigger signal provided by the original PXI specification. PXI Express also adds a 100 MHz differential clock and differential star triggers to the backplane to offer increased noise immunity and industry-leading synchronization accuracy (250 ps and 500 ps of module-to-module skew, respectively). NI timing and synchronization modules are designed to take advantage of the advanced timing and triggering technology featured in its PXI and PXI Express chassis.
PXIe-1085 System Architecture
The main advantages of PCI Express are the following:
Graphical Programming Platform LabVIEW
LabVIEW (short for Laboratory Virtual Instrument Engineering Workbench) is a system-design platform and development environment for a visual programming language from National Instruments.
The graphical language is named "G" (not to be confused with G-code).
VI stands for Virtual Instrument, the basic building block of programs written in LabVIEW. It is similar to a function or subroutine in other programming languages. It includes the Front Panel (containing Controls and Indicators), the Block Diagram (containing Control Terminals, Wires, and Structures and various other GObject nodes), the VI's Icon and its Connector Panel (as well as compiled executable code which is hidden behind the scenes).
The term Virtual Instrument is a play off of the fact that LabVIEW applications are designed for writing software that simulates the functionality of instruments -- rather than being a physical instrument on a laboratory bench, they are virtual and exist in software.
LabVIEW VIs are saved as *.vi files in a proprietary binary format defined by National Instruments, the makers of LabVIEW.
Originally released for the Apple Macintosh in 1986, LabVIEW is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, Mac OS X various versions of UNIX, Linux and Real-Time Operating System (RTOS).
The glue that ties everything together, is NI LabVIEW software that enables the user to define (or program) NI hardware to do acquire, analyze, and present the data they are measuring.
Addtionally to great hardware support LabVIEW has:
Every year in August appears the new version of LabVIEW . LabVIEW is constantly progressing.
1. NI CompactDAQ Hardware
NI CompactDAQ is a small, modular data acquisition system capable of analog I/O, digital I/O, counter/timer operations, industrial bus communication, and sensor and electrical measurements. An NI CompactDAQ system consists of a chassis and NI C Series I/O modules.
1. C Series Modules
Choose from more than 60 NI C Series modules for different measurements including thermocouple, voltage, resistance temperature detector, current, resistance, strain, digital (TTL and other), accelerometer, and microphone. Channel counts on the individual modules range from three to 32 channels to accommodate a wide range of system requirements. C Series modules combine signal conditioning, connectivity, and data acquisition into a small module for each specific measurement type, which reduces system complexity and increases measurement accuracy. Insert these modules into any C Series chassis to create a system that meets your specific application needs. Finally, you can create a mix of channel counts and measurement types within one system by selecting the desired modules and installing them into one of several C Series systems. With NI CompactDAQ, you can build the right system to meet the needs of your measurement application.
Figure 1. Choose from more than 60 NI C Series measurement modules.
NI C Series modules combine A/D converters, signal conditioning, and signal connectivity in one package for measuring or generating one or more specific types of signal. C Series I/O modules are hot-swappable and automatically detected by the NI CompactDAQ chassis. I/O channels are accessible using the NI-DAQmx driver software.
Because the modules contain built-in signal conditioning for extended voltage ranges or industrial signal types, you typically make your wiring connections directly from the C Series I/O modules to your sensors/actuators. In most cases, the C Series I/O modules provide isolation from channel-to-earth ground. Check each module's specifications for more details.
2. Integrated Processor and Storage
NI CompactDAQ controllers further the integration of your data acquisition system by combining the processor and data storage with the data acquisition and signal conditioning in a small, rugged form factor. NI has partnered with Intel to bring the latest industrial processors, such as the dual-core Atom, i7, and Celeron chips, to the data acquisition market.
Learn more about the advantages of using an NI CompactDAQ controller.
3. Mechanical Design
Instrumentation placement and installation are important parts of a test setup. You can minimize surrounding electrical noise by placing instrumentation close to the test subject because the digital signals used by USB, Ethernet, 802.11 WiFi, and several other protocols are less susceptible to electromagnetic interference. NI CompactDAQ can measure many channels in a small, rugged package so that you can place it close to the unit under test. NI CompactDAQ systems offer the following mechanical design features:
Rugged, Versatile Chassis With Flexible Mounting Options
Figure 2. NI CompactDAQ chassis offer 1-, 4-, or 8-slot options.
Cable and Signal Wire Strain Relief for Solid Connections
Built-In Trigger Lines for Import/Export of Digital Clocks
Figure 3. Close-up of power input, BNC trigger lines, and locking USB port on the NI cDAQ-9178
Automatic Synchronization of Modules and Channels
Visit the NI CompactDAQ chassis model page for prices and ordering information.
NI CompactDAQ USB Chassis
The NI cDAQ-9178 (eight slots), NI cDAQ-9174 (four slots), and NI cDAQ-9171 (one slot) USB chassis are designed for one to eight C Series I/O modules. The chassis are capable of measuring a broad range of analog and digital I/O signals and sensors over a Hi-Speed USB 2.0 interface.
Figure 1. cDAQ-9178 Chassis: (1) USB Connector, (2) TRIG 0 and 1 BNC Connector, (3) USB Cable Strain Relief, (4) 9-30 VDC Power Connector, (5) Module Slots, (6) Installed C Series modules, and (7) Chassis Grounding Screw
Figure 2. cDAQ-9174 Chassis: (1) USB Connector, (2) USB Cable Strain Relief, (3) 9-30 VDC Power Connector, (4) Module Slots, and (5) Chassis Grounding Screw
Figure 3. cDAQ-9171 Chassis: (1) ACTIVE and READY Status LEDs, (2) USB Connector with Strain Relief, (3) Chassis Grounding Screw, (4) Module Slot
The NI cDAQ-9188/9188XT (eight slots), NI cDAQ-9184 (four slots), and the NI cDAQ-9181 (one slot) Ethernet chassis are designed for one to eight C Series I/O modules. They are capable of measuring a broad range of analog and digital I/O signals and sensors over an IEEE 802.3ab Gigabit Ethernet interface.
Figure 4. cDAQ-9188/9188XT Chassis: (1) Chassis Grounding Screw, (2) Installed C Series Modules, (3) Module Slots, (4) 9-30 VDC Power Connector, (5) Reset Button, (6) PFI 0/1 BNC Connector, and (7) Ethernet Connector
Figure 5. cDAQ-9184 Chassis: (1) Chassis Grounding Screw, (2) Installed C Series Modules, (3) Module Slots, (4) Ethernet Connector, (5) 9-30 VDC Power Connector, (6) Reset Button, and (7) Status LEDs
Figure 6. cDAQ-9181 Chassis: (1) 9-30 VDC Power Connector, (2) Ethernet Connector, 10/100 and LINK/ACT LEDs, (3) Reset Button, (4) POWER, STATUS, and ACTIVE LEDs, (5) Chassis Grounding Screw, (6) Module Slot
The NI cDAQ-9191 (one slot) wireless chassis is designed for one C Series I/O module. It is capable of measuring a broad range of analog and digital I/O signals and sensors over IEEE 802.3ab Gigabit Ethernet interface for a wired connection or IEEE 802.11 Wi-Fi for wireless streaming.
Figure 7. cDAQ-9191 Chassis: (1) Antenna and Antenna Connector, (2) 9-30 VDC Power Connector, (3) Ethernet Connector, 10/100 and LINK/ACT LEDs, (4) Reset Button, (5) POWER, STATUS, and ACTIVE LEDs, (6) Wireless Signal Strength LEDs , (7) Chassis Grounding Screw, (8) Module Slot
4. Multiple Timing Engines for Multiple Acquisition Rates
A vital piece of a data acquisition system is the A/D converter. A/D converters need clock signals to designate when to acquire samples. Many systems have multiple A/D converters that share the same clock to synchronize all of the channels’ measurements. NI CompactDAQ systems have the advantage of flexibility when it comes to timing engines and go beyond standard synchronization.
Multiple Timing Engines for Multiple Rates
NI CompactDAQ chassis have three analog input timing engines. This makes it possible for programmers to divide all of their analog inputs in up to three different groups known as tasks.
Designated Timing Engines for Digital and Analog Output
NI CompactDAQ was designed to perform up to seven tasks simultaneously. You can choose from several task options:
By having a designated resource, digital and analog output tasks can run independently without having to share a clock signal from another task. This makes the programming easier and more intuitive. Designated resources can be shared with other subsystems of the chassis. For example, you can share the digital input clock with the analog output clock to generate a voltage with every rising/falling edge of the digital input.
The multiple timing engines and ability to route and share resources provide a level of flexibility to NI CompactDAQ unequaled by most off-the-shelf data acquisition systems.
Figure 4. This image depicts different analog input tasks running at different rates in the same chassis.
5. Advanced Counter Functionality From NI-STC 3 Technology
Some of the core technology in NI CompactDAQ chassis is shared with other NI data acquisition products. This technology is known as the third generation of the system timing controller (NI-STC3). Many devices use off-the-shelf clocks and oscillators for system timing. NI technology is designed for performance from the ground up, starting with the timing engines and 30 years of PC-based instrumentation experience. NI-STC3 technology is proprietary source code that is built into an ASIC and separates systems like NI CompactDAQ from all other devices on the market.
Four Advanced 32-Bit Counter/Timers
Figure 4. Diagram of Counter 0 and Frequency Generator is shown
Built-In Frequency Generator
Advanced Counter and Digital Features
6. NI Signal Streaming Technology
Communication buses, such as USB, Ethernet, and 802.11 WiFi, have a standardized data structure and a defined method of how a device communicates with the host, but not all devices are created equal. Patented NI Signal Streaming technology sets out to operate NI data acquisition devices most efficiently within the bounds of these bus standards. Many consumer products need only one or two streams of directional data. Music players and storage devices often move large quantities of data in one direction, updating to or from the host PC. Test systems often involve multiple inputs and outputs running simultaneously. NI Signal Streaming enables high-speed, bidirectional data streaming to and from the NI CompactDAQ system.
Figure 5. NI Signal Streaming technology enables parallel streaming of data from multiple tasks with minimal processor involvement.
Read more about NI Signal Streaming technology.
7. Software Options with NI CompactDAQ
With NI CompactDAQ systems, you can develop measurement and test applications in multiple programming environments, including ANSI C/C++, Visual C#, and Visual Basic .NET. However, tight hardware and software integration makes the NI LabVIEW graphical development environment the best choice for getting the most performance out of your NI CompactDAQ system with the least programming effort.
LabVIEW is a graphical programming environment for developing sophisticated measurement, test, and control systems using intuitive graphical icons and wires that resemble a flowchart. LabVIEW offers unrivaled integration with thousands of hardware devices, including the NI CompactDAQ platform, and provides hundreds of built-in libraries for advanced analysis and data visualization. You can automate measurements from several devices, analyze data in real time, and create custom reports in just minutes using this industry-standard tool.
Before you begin using your NI CompactDAQ hardware, you must install your application development environment (ADE) and NI-DAQmx driver software. Refer to the Installing NI LabVIEW and NI-DAQmx document for more information.
Figure 6. Graphical programming and dataflow representation make you more productive, enabling you to program just like you think.
8. Setting Up NI CompactDAQ Hardware
Complete the following steps to prepare your CompactDAQ chassis for use:
Figure 14. Ring Lug Attached to Chassis Ground
Figure 15. Installing C Series I/O Modules: (1) USB or Ethernet Connector and (2) C Series I/O Module
Figure 16. Network Configurations for NI CompactDAQ Ethernet Chassis
Complete the following steps to configure your NI-DAQmx software for use with NI CompactDAQ USB chassis:
Figure 17. NI Device Monitor
Figure 18. NI MAX
Figure 19. Self-Test
Complete the following steps to configure your NI-DAQmx software for use with NI CompactDAQ Ethernet chassis:
If your Network DAQ device is not listed, right-click Network Devices, and select Find Network NI-DAQmx Devices. In the Add Device Manually field, type the hostname or IP address of the Network DAQ device, click the + button, and click Add Selected Devices. Or if your chassis is automatically detected on the network, it will appear under the Available Devices section. Select this device and click Add Selected Devices. Your device will be added under Devices and Interfaces»Network Devices.
Figure 20. Find Network NI-DAQmx Devices
If you still cannot access your NI cDAQ-9181/9184/9188/9188XT chassis, select the “Click here for troubleshooting tips if your device does not appear” link in the Find Network NI-DAQmx Devices window or view additional troubleshooting resources.
Figure 21. IP Address Settings
Figure 22. System Settings in NI MAX
Figure 23. Self-Test
Complete the following steps to configure your NI-DAQmx software for use with NI CompactDAQ Wireless Chassis:
Figure 24. Find Network NI-DAQmx Devices
Figure 25. System Settings in NI MAX
If you still cannot access your NI cDAQ-9181/9184/9188/9188XT chassis, select the “Click here for troubleshooting tips if your device does not appear” link in the Find Network NI-DAQmx Devices window or view additional troubleshooting resources.
Figure 26. Selecting Country for Wireless
Figure 27. Configuring Wireless Mode
Figure 28. System Settings in NI MAX With Ethernet and Wireless Mode Enabled
Figure 29. System Settings in NI MAX with Wireless Mode Enabled
Figure 30. Self-Test
As an alternative to MAX, the cDAQ-9184/9188/9188XT/9191 chassis hosts a Web server from which you can configure network, security, firmware, and other system settings. Complete the following steps to configure your NI CompactDAQ Ethernet or wireless chassis through a Web browser:
Alternatively, you can use the NI Network Browser (located in the National Instruments start menu folder on your host computer) to find chassis on your local subnet.
Figure 31. Web-Based Configuration and Monitoring
Mounting NI CompactDAQ Hardware
You can mount an NI CompactDAQ Chassis using a desktop mounting kit, 35 mm DIN rail mounting kit, or panel mount accessory kit.
The NI 9901 desktop mounting kit includes two metal feet you can install on the sides of the NI CompactDAQ Chassis for desktop use. With this kit, you can tilt the NI CompactDAQ Chassis for convenient access to the I/O module connectors. When you install the two metal feet, the two existing screws on the back side and I/O end of the chassis must be removed, as shown in Figure 6. After removing the screws, replace them with the two longer screws included in the NI 9901 desktop mounting kit. The NI 9901 desktop mounting kit can be used with the following NI CompactDAQ Chassis:
Figure 9. NI 9901 Desktop Mounting Kit
Each DIN-rail kit contains one clip for mounting the chassis on a standard 35 mm DIN rail. To mount the chassis on a DIN rail, fasten the DIN-rail clip to the chassis using a No. 2 Phillips screwdriver and two M4 X 17 screws. The screws are included in the DIN-rail kit. Make sure the DIN-rail kit is installed as illustrated in Figure 7, with the larger lip of the DIN rail positioned up. When the DIN-rail kit is properly installed, the CompactDAQ chassis is centered on the DIN rail. Use the following kits for each chassis:
Figure 10. DIN-Rail Installation on cDAQ-9178 or cDAQ-9188/9188XT
Figure 11. DIN-Rail Installation on cDAQ-9181 or cDAQ-9191
To mount the chassis on a panel, align the chassis on the panel mount accessory. Attach the chassis to the panel mount kit using two M4 X 17 screws. National Instruments provides these screws with the panel mount kit. You must use these screws because they are the correct depth and thread for the panel. These slots in the panel mount kit can be used with M4, M5, No. 8, or No.10 panhead screws. Figure 8 illustrates the panel dimensions and installation on the CompactDAQ chassis. Refer to the documentation included with the panel mount kit for more detailed dimensions. Use the following kits for each chassis:
Figure 12. Panel Mount Installation on cDAQ-9178 or cDAQ-9188/9188XT
Figure 13. Panel Mount Installation on cDAQ-9181 or cDAQ-9191
For the cDAQ-9171 chassis, you do not need a kit for panel mounting. Two keyholes are located on the NI cDAQ-9171 for mounting it to a panel or wall. You can panel mount the NI cDAQ-9171 with either #6-32 panhead machine screws or M3.5 panhead machine screws. Installed screw height for both screw types is 7.37 mm (0.29 in.). Refer to the NI cDAQ-9171 Specifications for mounting dimensions.