LabVIEW: test bench for gas analysis

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The role of this test bench is the analysis and quality control of gas cylinders used in metallurgical industries, chemical, petrochemical, pharmaceutical and food industry.
The control system of gas is functionally decomposed as follows:
  1. Entering management and production information of gas
  2. Measuring the gases composition,
  3. Analysis of measures and results,
  4. Archiving data to a remote database.
The bench contains the following elements:
  1. Gas delivery system,
  2. Measurement instrumentation,
  3. Acquisition and control central,
  4. Management and supervision software.
Supervision software for analyzing gas written in LabVIEW
User interface of the supervision software for the gaz analysis bench

Harware technology

The supervision software is installed on a PC. The acquisition and control central is composed of Compact Fieldpoint modules of National Instruments. Gas analyzers are Emerson Process.

centrale d'aquisition et de commande compact fieldpoint

Compact Fieldpoint acquisition central and its cards

The supervisor, on the PC, is linked to central by a serial link (RS232). The central commands 0/24V switches to route gas to the analyzer. The central commands analyzers by 4-20mA.

Software technology

Operating system: MS Windows XP
Supervisor programing: Graphical programation with LabVIEW of National Instruments
Database: remote managed by WinDev
Supervisor-remote database comunication: Citrix network via FTP gateway

How does it work?

The analysis of a gas is performed by a measuring instrument called analyzer. This analyzer detects only certain chemical compounds. Therefore, to test several gas, it takes several analyzers.
The bench is composed nine analytical analyzers. To test the quality of a gas, it must send it to the analyzer which is sensitive to its characteristics.
The gas analyzers are routed through a network of pipes. By actuating the valves manually or by the supervision software, it is possible to direct gas.