November 2008

Focus on data acquisition

Data acquisition systems are products and/or processes used to collect information to document or analyze an event. A technician logging the temperature of an oven in a notebook is a simple example of performing data acquisition. Equipment ranges from simple recorders to sophisticated computer systems. Data acquisition products serve as a focal point in a system; they tie together a variety of products, such as sensors that indicate temperature, flow, level, or pressure. The sample rate is the speed at which a data acquisition system collects data. The speed is normally expressed in samples per second.

PCI bus A/D boards

The OME-PCI-1002 series is a family of PCI bus A/D boards. They feature a 110 KHz data acquisition under DOS and Windows. The boards provide 32 single-ended or 16 differential inputs, 16 digital input, and 16 digital output channels. The -H means high gain model, and the -L means low gain model.

The OME-PCI-1002 series provides three flexible external trigger modes: post-trigger, pre-trigger, and middle trigger. All boards are supplied with a standard software development kit for Windows 98/NT/2000/XP. The software development kit includes DLL files for programming in C, C++, or other high level languages and OCX files for Visual Basic or Active X programming. LabView drivers are also included.

An OME-DB-8025 screw terminal panel can be used to connect to the digital I/O lines. The OME-DB-16P isolated digital input board and OME-DB-16R relay board can be used to connect the digital I/O on the OME-PCI-1002 to real world signals. In order to connect to analog and digital signals a variety of terminal panels, digital input and relay boards are available for the OME-PCI-1002.


OMEGA Engineering

Data acquisition system

The isoLynx SLX200 data acquisition system implements industry standard Modbus RTU and TCP protocols and enables communication with a wide variety of existing third-party software drivers and HMI/SCADA packages. Fully certified by the Modbus-IDA organization and also compatible with OPC, the SLX200 provides reliability, accuracy, and isolation for a wide range of rugged high performance industrial applications. With its ability to interface with more than 650 SCM5B analog I/O modules, the SLX200 offers maximum flexibility for factory automation, process control, test and measurement, machine control, and data acquisition applications.

The communication protocol is Modbus RTU for RS-232/RS-485 or Modbus TCP for Ethernet. The SLX200's full certification ensures the device can be easily integrated onto existing Modbus networks, and most common Modbus function codes (1, 2, 3, 4, 5, 6, 15, 16, 23) are supported. The flexible, modular design of the SLX200 combines a 12-channel I/O controller base system and optional 8- or 16-channel expansion backplanes, which can be either panel or DIN rail mounted. The system accepts single-channel digital or analog I/O modules. All I/O is channel-to-channel and channel-to-bus isolated. 


Dataforth Corporation

Wi-Fi, Ethernet DAQ

Ten new Wi-Fi and Ethernet data acquisition (DAQ) devices include built-in signal conditioning and direct sensor connectivity for electrical, physical, mechanical and acoustic signals. Engineers and scientists can combine the company's Wi-Fi DAQ with the NI LabVIEW software platform to meet their wireless structural diagnostic, environmental, and machine condition monitoring application needs by reducing cabling costs and increasing flexibility without compromising performance.

Using the IEEE 802.11 standard for wireless networks, the Wi-Fi DAQ devices stream data on each channel at more than 50 kS/s with 24 bits of resolution. Wi-Fi DAQ devices deliver measurement data to a host PC instantaneously for real-time viewing and in-line analysis of dynamic sensor signals. In addition, built-in advanced network authentication methods and 128-bit AES encryption offer the highest commercially available network security and meet the standards defined for use of wireless networks in U.S. government facilities by the National Institute of Standards and Technology (NIST).

The Wi-Fi and Ethernet DAQ devices are shipped with NI-DAQmx driver software and NI LabVIEW SignalExpress LE, an interactive data-logging software for quickly acquiring, analyzing, and presenting data with no programming required. The NI-DAQmx driver delivers time-saving features such as the configuration-based NI DAQ Assistant with code generation for both LabVIEW and text-based languages; more than 3,000 measurement examples; device simulation; connection diagrams; and compatibility with LabVIEW, ANSI C/C++, C#, Visual Basic .NET, and Visual Basic 6.0.


National Instruments