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Oven Process Controller for the Processing of Medical Device
Components
Products Used
LabVIEW 7.0
LabVIEW DSC Module 7.0
LabVIEW RT 7.0
FieldPoint 4.0.2
cFP-2020
cFP-AI-110
cFP-RLY-421
The Challenge
Developing a scalable, distributed, and reliable oven
controller system that must also be controllable via a
web interface. Since this system processes medical device
parts, it must also maintain previous LabVIEW validated
code investment and move towards 21CFR part 11 compliance.
The Solution
Aside from the short turn-around time, the system called
for a development platform that would support fast and
reliable data acquisition as well as image processing.
An integrated environment that supports SQL capabilities
and SPC trending while communicating to a badge-handling
turntable via an Allen-Bradley SLC 504 PLC is also required.
LabVIEW and other National Instruments software and hardware
packages provided the best platforms to develop the solution.
Abstract
Using LabVIEW 7.0, LabVIEW RT 7.0, and the DSC Toolkit,
V I Engineering was able to develop a distributed, scalable,
and reliable oven controller system which processes a
critical component of a medical device. Compact FieldPoint
controllers running LabVIEW RT 7.0 actually perform the
customizable process sequences. LabVIEW DSC allows for
easy communication setup and programming between the multiple
controllers and the server. LabVIEW DSC’s built-in
Citadel database reliably logs critical process data.
In addition, LabVIEW’s web server serves up independent
client user interfaces to an unlimited number of users
within the enterprise..
The 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. They 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.
Since 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 clustered in close proximity to each other. Therefore,
the medical device manufacturer contacted V I Engineering
to help 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 be
able to cluster all ovens within close proximity
A web enabled system in order to allow for any authorized
user to 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 in order 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.
The Results
In order to meet the customer’s requirements, the
system was designed to run the actual processing and oven
control process on new Compact FieldPoint controllers
(cFP-2020). A cFP-AI-100 was used to measure oven pressures
and temperatures. A cFP-RLY-421was used to control the
oven heater control and pressure control. In order to
retain the existing investment in the BridgeVIEW 2.0 code,
the core process code was extracted from the previous
code that was written to run on a PC and with minor modifications
to run instead on the cFP-2020 in a real-time environment.
Due to the modular nature of LabVIEW, some server functions
such as the process configuration file creation could
be brought over to the new system relatively unchanged.
Other configuration utilities that had to now work with
an unlimited number of ovens could still be saved from
the original system with modifications. The one part of
the new system that had to be written from scratch was
the new web based user interfaces. Using LabVIEW’s
built-in web server and dynamically called vi’s
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, the
user authenticates against their corporate network account
via Active Directory (for 21CFR part 11 compliance ) and
DSC authentication information. Upon 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. (See diagram 1.) 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's tag configuration and FieldPoint LabVIEW tags, communication between the server and oven controllers was easy to setup and implement. Adding oven controller to the system requires no additional programming. Only the new controller tag information needs to be added to the DSC tag configuration. In addition, since 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's built-in compact flash drive so that when the network is back on-line, the server downloads process data via the LabVIEW RT's built-in ftp server.
Since the oven controllers are running LabVIEW RT independently, an unexpected server reboot, which is common due to patches from the network administrator, will not cause any ill effects on the oven controllers. Upon reboot, the server and Compact FieldPoint oven controllers will re-synchronize. Users on the web clients will still have accurate and up to date process status information.
Conclusion
With the use of LabVIEW 7.0, DSC, and RT along with the Compact FieldPoint platform, V I Engineering was able to develop a distributed, reliable, scalable, and web enabled oven process controller that also retained much of the existing BridgeVIEW code investment. LabVIEW RT and the Compact FieldPoint platform have proven to be reliable enough to process a critical component used in an implantable medical device. LabVIEW 7.0 with the DSC toolkit allowed users throughout the entire enterprise to view an instant current system overview or historical data details stored in Citadel.
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