Customer Solutions

Wireless Data Acquisition Improves Paper Mill

Author(s):

Phil Taber, AstenJohnson; Bob Myers, n/a

Industry:

Pulp/Paper

Product:

Data Acquisition, LabVIEW, Signal Conditioning

The Challenge:

Setting up instrumentation to measure process instabilities in a paper mill, a difficult environment for routing cables.

The Solution:

Combining SCXI, LabVIEW, and ViaSat MiniDAT for wireless data acquisition.

AstenJohnson designs, manufactures, and markets paper machine clothing for all sections of the paper machine. Paper machine clothing is a highly engineered textile fabric installed on paper machines to carry the paper stock through each stage of the paper making process.

To meet customer needs, AstenJohnson provides the Diagnostic Service Group, comprised of papermakers and diagnostic engineers, to help the customer troubleshoot, identify, and solve machine productivity issues. When a problem cannot be identified using conventional papermaking methods, they use electronic diagnostic equipment to measure process instabilities.

Typical Machine Setup
We condition all signals using the National Instruments SCXI-1001, 12-slot chassis. This chassis is equipped with SCXI modules that provide 34 channels of signal conditioning for pressure, vibration, triggers, and several specialty sensors. We setup the chassis in multiplexed mode using the NI-DAQsoftware driver and a DAQCard-AI-16XE-50 PCMCIA card. We record and analyze all signals using a custom analysis package written specifically for AstenJohnson in LabVIEW.

Most of the required test points are located on the wet end of the machine in the stock approach system. Therefore, we set up the SCXI chassis and laptop computer on the wet end of the machine and dispatched 100 ft cables to the individual test points in the approach system, including the basement. To measure the impact the variations in the stock approach system have on the sheet quality, we access the online basis weight signal on the dry end of the machine. The distance between the wet and dry end of many of the machines measured is typically 400 to 500 ft and requires stringing 100 ft cables together from one end of the machine to the other. The cables pose an extreme safety risk because they must be laid on the floor and routed around section drives, line shafts, and stock chests.

Wireless Data Acquisition
ViaSat MiniDAT provides a high-speed, multichannel, networked, wireless link between the dry end process signals and laptop computer simultaneously accessing data from the SCXI chassis, eliminating the need to run long cables from one end of the machine to the other. By connecting the MiniDAT directly to the SCXI-1001 chassis, we have direct access to all signals from a remote location. This is especially useful when making changes to machine operating parameters. We can locate the analyst and laptop computer in the machine control room providing direct feedback of the changes on the papermaking process. Each MiniDAT has its own IP address making it possible to access several devices at various locations on the machine. Because of this, we have considered installing the diagnostic instrumentation at a mill site and troubleshooting over the Internet.

We also use the MiniDAT to access signals from an SCXI-1000, 4-slot chassis. This chassis provides 15 channels of pressure, trigger, and specialty sensor signal conditioning. We use this at mill sites that provide no immediate access for the 100 ft cables to be run to pressure tap locations in the basement of the machine. By using the MiniDAT, we access the signals from the SCXI-1000 chassis through the concrete machine room floor.

For more information, contact:

Phil Taber

Tel: (843) 549-3033

E-mail: phil.taber@astenjohnson.com

astenjohnson.pdf

View the entire user solution in Adobe Acrobat PDF format.