March 2008

Focus on signal conditioning

To process the form or mode of a signal so as to make it intelligible to, or compatible with, a given device, including such manipulation as pulse shaping, pulse clipping, compensating, digitizing, and linearizing. In electronics, signal conditioning means manipulating an analogue signal in such a way that it meets the requirements of the next stage for further processing. In control engineering applications, it is common to have a sensing stage, a signal conditioning stage, and a processing stage. It is often utilized for data acquisition, in which sensor signals must be normalized and filtered to levels suitable for analog-to-digital conversion so they can be read by computerized devices.

USB single module carrier

The C Series USB single module carrier is a low-channel-count, low-cost, and highly portable solution for NI C Series modules. In addition to stand-alone application use, you can deploy the single module carrier as a debugging device for larger systems or use it to prototype sensor connections before you integrate modules into an NI CompactRIO system. You can use the modules that work with the NI USB single module carrier in any C Series chassis such as NI CompactDAQ, CompactRIO, or R Series expansion chassis. Operating temperature range is 0 to 60°C. LabVIEW SignalExpress LE data-logging software is available.

National Instruments
www.ni.com

mar2

Analog system adapter

A new analog system adapter is for use with the company's MINI MCR line of isolators and converters.  With the adapter, the user can plug the system cables directly from the analog isolators or converters, and into the controllers, drastically reducing wiring time.  This approach is significantly faster than single-core PLC wiring and also reduces the potential for human error.  The system adapters have received a wide range of certifications and can be used in Ex Zone 2 environments. 
 
Phoenix Contact
www.phoenixcontact.com

mar3

Differential ADC driver

The LTC6400-20 is a high-speed differential amplifier targeted at processing signals from DC to 300MHz. The part has been specifically designed to drive 12-, 14-, and 16-bit ADCs with low noise and low distortion, but can also be used as a general-purpose broadband gain block.

The LTC6400-20 is easy to use, with minimal support circuitry required. The output common mode voltage is set using an external pin, independent of the inputs, which eliminates the need for transformers or AC-coupling capacitors in many applications. The gain is internally fixed at 20dB (10V/V).

The LTC6400-20 saves space and power compared to alternative solutions using IF gain blocks and transformers. The LTC6400-20 is packaged in a compact 16-lead 3mm x 3mm QFN package and operates over the -40°C to 85°C temperature range.

Linear Technology
www.linear.com

Control, monitoring software system 

The SLX920 input-output network, combined with one or more isoLynx SLX200 systems, provides a total solution for factory automation, process control, test and measurement, machine control, and data acquisition applications.

The core software runs as a service under Windows. This sets up the central server, which can connect to many isoLynx SLX200 units via one or more networks. The networks can be EIA-485 or dedicated Ethernets, or a combination of the two. Users then access the system via an Intranet or the Internet. No application software is required because the HMI is delivered via web browsers. Dynamic real-time graphical displays are generated on the web pages by the SLX920-Graphic Java applet.

The administrator easily creates an I/O website using the SLX920-Designer. The SLX920-Designer allows dynamic real-time graphical objects such as pie charts, histograms, graphs, and mimics to be created using a graphical user interface. When viewed in the users' browsers, these graphical displays respond in real-time to external signals. The input data to the graphics comes from the SCM5B isolated analog signal conditioning modules that are inserted in the isoLynx SLX200 units.

A lossless data historian is built into the SLX920. The historian runs automatically and continuously captures data at regular intervals. This historized data then may be used to generate history tables or graphs. The SLX920 also provides for the exchange of current and historical data with other applications via XML; in addition, users can create Excel spreadsheets using current and historical data.

Dataforth Corporation 
www.dataforth.com