Customer Solutions

LabVIEW Datalogging and Supervisory Control Module Saves Downtime on Aerospace Milling Machine

Author: Don Seidenspinner, Spincraft Engineering Inc.

The Challenge: Developing a maintenance system to predict failure of critical mill components.

The Solution: Using LabVIEW Datalogging and Supervisory Control Module and data acquisition (DAQ) boards to create a PC-based monitoring system with accelerometers from Endevco.
The Boeing Corp. plant at Huntington Beach, CA, uses a Cincinnati Milacron Skin Mill to perform the precision shaping of large aluminum extrusions. The aluminum material is fastened to a "bed" that is more than 20 by 40 ft long. After shaping, the final product acts as the "skin" of spacecraft and aircraft, hence the name "Skin Mill." The failure of critical machine components was causing unacceptable downtime, costly repairs, plus loss of material.
System Configuration
Spincraft Engineering Inc., a full-service systems integration company, was invited to study the problem faced by Boeing, and to suggest a practical, reliable solution. We chose to use National Instruments LabVIEW Datalogging and Supervisory Control Module and data acquisition (DAQ) boards to create a predictive maintenance system. This system continuously monitors signals from seven Endevco accelerometers mounted in close proximity to the motor-shaft bearings, drill bit, and other critical areas on the machine. These Endevco piezoelectric sensors generate analog signals that measure the component vibration. The pre-amplifier, also made by Endevco, powers the sensors. We found typical signal amplitudes in the order of 1 mV, corresponding to a force of approximately 1 g of component vibration, with a spectral content ranging from 1 Hz to 10 kHz fundamental frequencies.

The outputs from the sensors are fed to a National Instruments data acquisition board. The board generates 16-bit digitized data. The resultant signatures, or wave envelopes, are then displayed on our rugged, "shoebox" PC, which includes a Pentium CPU local hard drive, network board, and 32 MB RAM.

We chose the National Instruments LabVIEW Datalogging and Supervisory Control Module graphical, SCADA development environment to create a user-friendly graphical user interface (GUI). We designed the GUI so that personnel of diverse technical backgrounds can operate the system.

With the final GUI, users have continuous graphical monitoring of the milling operation and can select various levels of response when registering anomalies or impending failure. Users can set the program to ignore a selected number of abnormal readings or to respond instantly to predetermined excursions from the norm. A typical system response is to alert the maintenance supervisor immediately for diagnosis or repair.

The system operator - a technician, maintenance person, or other designated person - is alerted to abnormal operation by a highly visible flashing light, audible signal, and on-screen warnings. Using the Internet Toolkit, you can monitor the system operational status using a Web browser. Dynamic vibration data plots are also available via the Web.

With the innovative Peak Detection VIs in the LabVIEW Datalogging and Supervisory Control Module , users can instantly compare dominant frequency peaks with established characteristic patterns produced during the milling operation. In addition, with LabVIEW Datalogging and Supervisory Control Module , users can accumulate data for historical review, with the capability of storing measurements made over a period of hours, days, or even years. Trend graphs can be displayed on the server, a remote view node, printed, or read off the Internet using a browser. We used the LabVIEW Datalogging and Supervisory Control Module to broadcast the graphs.

In addition to presentation of the data in graphical form, the vibration signature is analyzed for harmonic content because the harmonics are known to change with the mechanical wear. This analysis generally leads to the mechanical component that is wearing out. The Spincraft Engineering staff has consistently chosen LabVIEW Datalogging and Supervisory Control Module because of its flexible programming. With LabVIEW Datalogging and Supervisory Control Module , users can develop monitoring and automation systems that perform high-speed acquisition and manipulation of data as well as engineering of advanced process-control systems.

Spincraft Engineering, located in San Diego, is a supplier of demanding industrial systems for process control and data acquisition. For more information, use Contact Info link

Customer Solutions

LabVIEW DSC Application Monitors VVCD Plant

Author: Don Seidenspinner, Spincraft Engineering, Inc.
The Challenge: To design and develop the SCADA system responsible for monitoring and controlling a vacuum vapor control distillation plant.

The Solution: LabVIEW DSC was selected to implement this demanding application.

Advanced Distillation Technology (ADT), located in Sacramento, CA, needed a mobile desalinization plant to produce quality drinking water. ADT chose us, Spincraft Engineering, Inc, located in San Diego, CA, to design and develop the SCADA system responsible for monitoring and controlling the vacuum vapor control distillation (VVCD) plant.

We selected LabVIEW DSC to implement this demanding application. The intuitive graphical user interface (GUI), combined with the powerful graphical programming language, G, gave us a SCADA system capable of supervising the total plant. The VVCD SCADA system we developed with LabVIEW DSC provides a rapidly reconfigurable control system capable of monitoring a wide range of plant operational parameters, such as flow, pressure, and water quality.

The VVCD desalinization plant design needed to be easy and efficient to operate and maintain. In addition, ADT wanted a mobile system so they could easily move the plant to new locations; this is because mobile desalinization plants are used around the world in countries that have difficulty obtaining a reliable fresh drinking water supply. The portable VVCD plant, which is built into a van, has the capacity to provide a reliable fresh water supply from saltwater. Also, users can easily move the system to different populations as water is needed. A typical VVCD plant is composed of up to 20 identical purification modules, each capable of distilling salt water into potable water at a rate of up to 50,000 gallons per day.

System Configuration
The LabVIEW DSC SCADA application monitors and controls plant parameters necessary to maximize operating efficiency. The plant incorporates distributed, real-time controllers built with embedded PC-104-based microcontrollers that are networked together using a multidrop standard communications protocol. We implemented the MMI/SCADA application on a PC-based system running LabVIEW DSC on Windows NT 4.0 for enhanced security and stability. The prototype VVCD system implements the MODBUS protocol and will be upgradable to a Fieldbus protocol in the future.

Our challenge was to provide a SCADA system that would monitor and control a single VVCD module, and yet be robust enough to control the entire set of 20 modules that comprise the plant. We developed this feature in LabVIEW DSC to provide the operator with a hierarchy of user interface screen displays through which the user can easily navigate the system. We chose LabVIEW DSC because of its unique graphic capabilities, built-in network configurations, and connectivity to existing LabVIEW device drivers. Because G, the LabVIEW DSC built-in programming language, is graphical, it offers a unique combination of flexibility and ease of use to handle the most demanding data acquisition or control applications. G is well suited to handle automation applications that fall outside the well defined boundaries of scripting languages provided with many traditional MMI/SCADA software packages to perform complex analysis during real time operations. Users can draw their own automation solution using the extensive G graphical library, which includes functions for data acquisition, math analysis, GUI presentation, as well as connectivity to networks and other applications, such as Excel, using standards such as TCP/IP, OPC, and DDE.

Security
System security was important for this VVCD system because the plant is unattended for long periods of time. We provided access to the VVCD system to three classes of users - Operator, Supervisor, and Engineer. Logon access for each class of user is restricted via password protection. We maintain an access log file itemizing each Logon attempt with the resolution of the attempt. With LabVIEW DSC as the development and applications environment, we easily achieve this type of layered security.

Results
We delivered a working prototype of the VVCD automation system. With the capabilities of LabVIEW DSC, we implemented the distributed control functions required by this application in a straightforward manner and forged new ground in distributed high-performance control systems.

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