Lookout and FieldPoint Inspect Gasket Material

Author(s):
Mark Sherwin - MAS Associates

Industry:
Industrial Controls/ Devices/ Systems

Products:
Compact FieldPoint, Lookout, FieldPoint, Instrument Drivers/IVI,

The Challenge:
Measuring the thickness (caliper) and density of gasket material in an industrial environment on a mobile test stand.

The Solution:
Using National Instruments Lookout software and FieldPoint distributed I/O with an Octagon embedded computer to sense, control, display, analyze, and log the data.

Introduction
Lydall Composites of Hoosick Falls, New York, required an inspection machine with an operator interface, machine control, data acquisition, I/O communications, network communications, alarming, and data logging. From past experience, we knew it was important to incorporate the calendaring data under a more complete process database for future use. Because Lookout is PLC-compatible and FieldPoint can expand to include more I/O very easily, the combination of these two National Instruments products was exactly what we needed. It solved our immediate requirements and also provides for future process needs.

Configuration and Operation
The operator panel layout features a systemstart pushbutton, an emergency-stop pushbutton, and a hardened mouse pad. To ensure that the computer is in control of the machine, the built-in watchdog timer on FieldPoint keeps the emergency-stop circuit active. If the computer or program is interrupted for more than a few seconds, the conveyor and all active mechanical components will shut down.

As the gasket material proceeds on the conveyor into the measuring probes, it activates an electric eye. Lookout calculates speed, determines when to make measurements, and captures and logs data points. Once the sheet is clear of the electric eye, it is sent to the weighing table to capture the total sheet weight.
At this point, Lookout calculates the density of the sheet. As the "decide counter" sequences through each attribute, the operator observes which readings are irregular. The sheet, for instance, may exhibit an average value that falls within average tolerance parameters but that has a high spot in the sheet that would make it unacceptable. The operator then sorts the sheets for quality analysis later, while making the go/no-go decision.

With the inclusion of a trend chart and an operating screen, operations can be successfully troubleshooted. The electric eye, for example, is critical to the timing of the system. If it gets dirty or scratched, its signal level changes. The electrician can observe the sequence and use the history as a troubleshooting guide.

Testing the System
To test the system, we placed a 460 VAC inverter, which controls conveyor speed, in the same cabinet with the FieldPoint I/O. We temporarily wired the system to ensure its stability. FieldPoint controlled the motor with a 4 to 20 mA signal and read 20 mV on the module adjacent to the motor controller. Signal isolation was stable and remained stable throughout the running of the inspection table. While it is difficult to use space on a mobile machine efficiently, FieldPoint really passed the test. The person who built the machine had never seen I/O communications start up and run so easily. Other I/O arrangements that Lydall Composites tried have been balky and awkward to set up; however, "this one [FieldPoint] is a winner."

The Future of This System
For the future, we forsee the use of this system for PLC communications and speeds, with hydraulic pressure data added to the data collection output. The cost to implement this system is comparable to the cost of a wellknown PLC system that accomplishes logic functions and very limited data handling with no operator interface. If a PLC-based system had all of the features of this system, it would cost at least twice as much as this system and not be as effective.

For more information, contact:

Mark A. Sherwin President

MAS Associates, Inc.

1 Knolls Rd S.

Queensbury, NY

Tel: (518) 798-8270

Fax: (518) 743-1434

E-mail: masassoc@netheaven.com

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