Distributed Oven Process Controller Uses NI LabVIEW Real-Time to Process Medical Device Components

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LabVIEW DSC with LabVIEW Real-Time Controllers allow for unlimited Oven Process Controllers and users.

Author(s):
Brant Bergdoll - VI Engineering

Industry:
Medical/ Medical Instrumentation, Life Science

Products:
Compact FieldPoint, FieldPoint, LabVIEW Datalogging and Supervisory Control Module, LabVIEW

The Challenge:
Developing a scalable, distributed, and reliable oven controller system that a user can control through a Web interface while also maintainging a previous code investment validated by National Instruments LabVIEW validated code and move toward 21CFR part 11 compliance.

The Solution:
Creating reliable control code in NI LabVIEW Real-Time running on Compact FieldPoint real-time controller/interface targets to communicate to a central server program running LabVIEW 7.0 and the DSC Module.

Process Control System Requirements

Our customer is a world leader in the design and manufacture of medical devices used in treating cardiovascular diseases. The unit under process, a critical component to the final medical device, must undergo a series of heating and cooling cycles under various oven pressures for an extended period of time to adaptively dry the components.

The customer previously had an oven control system programmed in-house with BridgeVIEW 2.0. This solution could control up to four ovens via two duplicate FieldPoint configurations on a single PC. Because this single Windows-based PC was responsible for all user interfaces and process control, a system crash could result in the loss of entire batch of expensive components. This BridgeVIEW 2.0 and FieldPoint-based system served the customer well for R&D and low-volume production for some time. However, the customer’s product was ramping up in production volume. In addition, production was moving to a new facility in which ovens would not necessarily be in close proximity to each other. Therefore, the medical device manufacturer contacted V I Engineering to develop an oven control system that met the following requirements:

• A scalable system that can handle at least 10 ovens per server and allow for the addition of future ovens without additional programming.
• A reliable system in which a crash in one part of the system will not cause the loss of product or processing across the entire system. In addition, due to the critical nature of the part under process, data must be reliably stored on a central server.
• A distributed system as the new facility will not cluster all ovens within a close proximity to each other.
• A Web-enabled system so that an authorized user can view any oven’s status and allow the busy production manager to quickly view the entire system’s status at a glance from his Web browser.
• An economical system to retain the investment of the previously validated BridgeVIEW 2.0 code. As the unit under process is a component for an implantable medical device, the process system must undergo a rigorous validation. Validation takes a great deal of time to complete and investment from the customer.

Programming Made Easy with LabVIEW

To meet the customer’s requirements, we designed the system to run the actual processing and oven control process on new Compact FieldPoint controllers (cFP-2020 real-time controller/interface). We used a cFP-AI-100 analog input to measure oven pressures and temperatures. A cFP-RLY-421 relay controls the oven heater and pressure control. To retain the existing investment in the BridgeVIEW 2.0 code, we extracted the core process code from the previous code that was written to run on a PC and with minor modifications, programmed it to run on the cFP-2020 real-time controller/interface in a real-time environment. Due to the modular nature of LabVIEW, we brought some server functions such as the process configuration file creation to the new system relatively unchanged. We could still save other configuration utilities that had to now work with an unlimited number of ovens from the original system with modifications.

The one part of the new system that we had to write from scratch was the new Web-based user interfaces. With the LabVIEW built-in Web server and dynamically called VIs using VI templates, an unlimited number of clients could connect to the server and independently view the status of any oven. When a user wants control of an oven, they authenticate against their corporate network account via active directory (for 21CFR part 11 compliance) and DSC authentication information. After a successful login, the user can then start or stop a process, enter component batch information with an integrated RFID reader or 2D barcode reader, select and download a new process configuration, or even query the Citadel database for process data from any previous process run. With event structures that can sleep under idle conditions, the server, which is a standard PC, can handle the load of many concurrent users.

With LabVIEW DSC tag configuration and FieldPoint LabVIEW tags, communication between the server and oven controllers was easy to setup and implement. Adding oven controllers to the system requires no additional programming. Only the new controller tag information needs to be added to the DSC tag configuration. In addition, because the DSC engine automatically handles database logging, critical process data saving was also easily implemented. However, for redundancy in case of a network outage, process results are saved to the cFP-2020 real-time controller/interface’s built-in compact flash drive so that when the network is back on-line, the server downloads process data via the LabVIEW Real-Time built-in ftp server.

Because the oven controllers are running LabVIEW Real-Time independently, an unexpected server reboot, which is common due to patches from the network administrator, does not cause any ill effects on the oven controllers. After reboot, the server and Compact FieldPoint oven controllers re-synchronize. Users on the Web clients still have accurate and up to date process status information.

System Success

With the use of LabVIEW 7.0, the LabVIEW DSC Module, and LabVIEW Real-Time Module, along with the Compact FieldPoint platform, V I Engineering developed a distributed, reliable, scalable, and Web-enabled oven process controller that retained much of the existing BridgeVIEW code investment. LabVIEW Real-Time and the Compact FieldPoint platform have proven reliable enough to process a critical component used in an implantable medical device. With LabVIEW 7.0 and the DSC Module, users throughout the entire enterprise can view an instant current system overview or historical data details stored in Citadel.

For more information, contact:

Brant Bergdoll

Sr. Project Engineer

VI Engineering

37800 Hills Tech

Farmington Hills, MI 48331

Tel: (248) 489-1200

Fax: (248) 489-1904

E-mail: rrichard@viengineering.com

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