Building a Nuclear Reactor Control System Upgrade with NI LabVIEW and FieldPoint

Author(s):
Neal Pederson - VI Control Systems and Sandia National Laboratories

Industry:
Aerospace/Avionics

Products:
Compact FieldPoint, PXI/CompactPCI, LabVIEW, FieldPoint

The Challenge:
Replacing the control system of a research reactor with a modern, user-friendly, easy-to-maintain control system in a reasonable amount of time and cost.

The Solution:
Using an Ethernet network of nine PCs running Windows 2000 and LabVIEW with FieldPoint hardware, we configured two PCs with motion hardware and one with PCI-6602 timing cards to write efficient LabVIEW code to distribute to all nine PCs.

Development in One-Fifth of the Time
The previous control system for the Annular Core Research Reactor (ACRR) at our Sandia National Laboratories was difficult to maintain and upgrade because of obsolete, aging equipment. As a nuclear test and research reactor at SNL, we had to upgrade the system to provide strict reactor control and flexibility in equipment upgrades. The original equipment design and installation took 10 years. The system used 386-based computers running C programs under DOS, outdated data-acquisition and motion hardware, and PLC-based communications. We designed and installed a replacement system based primarily on NI software and hardware in less than two years.

A Comprehensive System Design
The new control system uses nine Pentium-III PCs running LabVIEW under Windows 2000, FieldPoint I/O hardware, PCI-6602 timing hardware, Delta Tau motion hardware, and Ethernet communications. The resulting system has a user-friendly operator interface and equipment that is easier and less expensive to maintain and upgrade.

We chose Ethernet for communications because of its durability and prevalence in industrial and business networks. A switching hub connects all nine of the control system’s PCs and all six FieldPoint FP-2000 network modules. The network is isolated for improved system stability and security. A DataSocket server runs on one PC providing communication between the nine networked PCs. Each PC has write privileges to one DataSocket data set, but all nine PCs can read from any of the data sets.

The software for the ACRR control system was written using LabVIEW 6.1 in a way that makes it easy to modify, maintain, and deploy to multiple PCs across the network.

Signal Mapping and Scaling
We set up a signals spreadsheet that maps tag names to either FieldPoint I/O channels or DataSocket variables. After editing, we save the spreadsheet as a tab-delimited text file that LabVIEW reads at startup. LabVIEW then maps the tag names to the appropriate hardware or DataSocket channels. The spreadsheet also includes scaling units for up to 5th order polynomials to convert FieldPoint raw data to engineering units. We found the signals spreadsheet very flexible because using it we can easily modify signal names, locations, and scaling units without changes to the LabVIEW code. During bench tests, the FieldPoint setup differed than we planned for the field. We could easily change the signals list to map I/O channels to available FieldPoint hardware and allow software testing of individual components.

I/O Simulator
We built a LabVIEW I/O simulator to perform software testing without hardware. We set up the LabVIEW FieldPoint and DataSocket I/O VIs to read and write simulated I/O signals if hardware was turned off in the settings.ini text file. The simulator VI injected input signals and read back output signals. We accomplished complete testing of software without connecting hardware. It worked for both FieldPoint and DataSocket signals and both digital and numerical signals. The simulator VI loaded and saved tab-delimited text files for easy recall of different simulation setups. Because the files were spreadsheet compatible, we also could edit the setups in Excel.


One Application for All Nine PCs

Maintaining code and creating LabVIEW executables for nine separate PCs can prove difficult. Much of the code is common between the computers. We needed nine PCs to provide multiple user interfaces simultaneously – not because of large code size. We designed the software as a single program to run and display different routines based on the host computer requirements. At startup, the program checks the local settings.ini file for self-identification. The software then loads the appropriate screens and runs the I/O routines required by that computer. Only one LabVIEW program is distributed and maintained between the nine PCs. The two motion control computers are located about 100 ft from the control room and are not normally used as a display. Because the computers include the same LabVIEW code, we could easily run the GUIs from the other seven computers in a read-only mode. In this way, we can view various parameters without walking back to the control room.

Software Health and Watchdogs
The system handles time-critical operations by discrete logic hardware or by the NI PCI-6602 timing boards. A program scan-time update and associated rotating graphic are displayed on every screen indicating proper operation of the LabVIEW code. The primary ACRR computer control system works with a 50 ms loop cycle time. Three of the nine computers continuously monitor each other and use a watchdog shutdown function. If any of the three computers do not update its watchdog through DataSocket every second, the other two computers initiate a watchdog shutdown and terminate reactor operations. This protects against computer crashes and network problems. We did not need FieldPoint real-time capabilities for this system, but installed FP-2000 real-time modules for upgrades in the future. Note that an independent Plant Protection System ensures reactor safety regardless of control system malfunctions or operator error.

Rugged, Easy-to-Maintain Control System
In summary, we installed a rugged and easy-to-maintain control system to replace an aging control system for the ACRR at SNL. The new system provides a better looking and more intuitive user interface, LabVIEW-based software that is easy to modify, and state-of-the-art National Instruments hardware that is inexpensive and easy to maintain. Programming the new system using LabVIEW reduced software development time by more than a factor of ten as compared to the time invested in C programming for the original system.

For more information, contact:
Neal Pederson
VI Control System
1923 Mendius Lane,
Los Alamos, NM 87544
Tel: 505-662-1461
Fax: 866-422-2931
E-Mail: np@vicontrols.com
or
R. Danny Beets
Sandia National Laboratories
PO BOX 5800, Albuquerque, NM 87185
Tel: 505-844-4535
Fax: 505-845-3115
E-Mail: rdbeets@sandia.gov

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