By measuring the amounts of the specific gases in the exhaust emissions, the R&D group that designs the systems to make the steel and aluminum can focus on optimizing the process, which will ultimately result in lower emissions.

Author(s):
Patrick de Boevere - Serenity Systems Design

Industry:
Machines/Mechanics, Process Industries

Products:
FieldPoint, LabVIEW

The Challenge:
Replacing an outdated industrial data acquisition and control system used to automate the measurement of gas emissions by steel and aluminum processing plants.

The Solution:
Developing a PC-based monitoring system using NI FieldPoint programmable automation controllers (PACs) and NI LabVIEW software.

In the 1990s, a major European producer of steel and aluminum products developed a custom mobile measurement system to automate the measurement and reporting of gases emitted from its various steel processing plants. The system consisted of a long, heated hose connected to a truck containing the measurement system, sensors, and an exhaust outlet. To comply with European emissions regulations, gas analyzers, generating 0 to 20 mA outputs, examined the gas mixture, temperature, and humidity in the area. The environmental department at the facility quickly developed a gooLd reputation for quality analysis and was often asked to perform the measurements at other companies.

However, by the year 2000, adequate technical support for the measurement system could no longer be guaranteed. The engineering team needed to continue to provide high-quality measurements and analysis but wanted a system using off-the-shelf components for easier maintenance. The system designers chose to develop a new system using LabVIEW software and FieldPoint hardware to meet these requirements, and they selected us to develop the software architecture for this system.

Software Architecture

We are Serenity systems design, a Dutch company with extensive experience using National Instruments development tools in measurement applications. Although we developed the new system as a replacement for an existing application, the upgrade we made also enhanced the functionality of the measurement system using the data processing and presentation capabilities of LabVIEW.

Our new system consists of a standard Windows PC and serially connected FieldPoint remote digital and analog I/O modules with industrial wiring. The benefits of this system include:

•    Increased sampling rate from 0.2 to 10 Hz

•    Enhanced display of the measurement process, both numerical and graphical

•    Addition of a calculation window showing all measured and calculated values

•   A calibration window with trending of the calibration signals

•   Five signals with separate warning and alarm levels also logged to file for operator notification

•   Simplified report generation

•   Data logging of measured and calculated signals for additional analysis on the measurements

System Operation

The software polls the FieldPoint system for new data at user-selected rates. New data points and calculated analysis values are constantly updated in the three databases, at the sample rate and in 5- and 60-second intervals. Also, during a measurement run, a new timestamped data line is added to an ASCII-coded data file every 60 seconds. The operator display consists of several windows:

•   A calculation window with 16 measured and 32 calculated signals.

•   A calibration window with a strip chart displaying a trend from a selection of six signals, with the current, 5- or 60-second average values, which is an important aspect of the program because frequent recalibration using reference gas mixtures enhances the accuracy of the measurements.

•   A main window with seven separate signals that can be graphically and numerically viewed as current, 5- or 60-second average values. This window also contains the operator that controls the buttons to start and stop the measurements.

The new system has proven to be more successful and provide more information on the exhaust gas emissions than the previous solution by taking advantage of both the higher sampling rate and increased resolution of FieldPoint. More accurate reporting of the content of exhaust fumes has resulted in an increased interest and research by our process engineering R&D group. By measuring the amounts of the specific gases in the exhaust emissions, the R&D group that designs the systems to make the steel and aluminum can focus on optimizing the process, which will ultimately result in lower emissions.

Finally, the increased capability of the system resulted in many satisfied internal customers and continued requests from outside the company for conducting exhaust measurements and analysis.

http://sine.ni.com/cs/app/doc/p/id/cs-11307