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Title: Status of the Control System on the National Spherical Torus Experiment (NSTX)

Abstract

In 2003, the NSTX plasma control system was used for plasma shape control using real-time equilibrium reconstruction (using the rtEFIT code - J. Ferron, et al., Nucl. Fusion 38 1055 (1998)). rtEFIT is now in routine use for plasma boundary control [D. A. Gates, et al., submitted to Nuclear Fusion (2005)]. More recently, the system has been upgraded to support feedback control of the resistive wall mode (RWM). This paper describes the hardware and software improvements that were made in support of these physics requirements. The real-time data acquisition system now acquires 352 channels of data at 5kHz for each NSTX plasma discharge. The latency for the data acquisition, which uses the FPDP (Front Panel Data Port) protocol, is measured to be {approx}8 microseconds. A Stand-Alone digitizer (SAD), designed at PPPL, along with an FPDP Input multiplexing module (FIMM) allows for simple modular upgrades. An interface module was built to interface between the FPDP output of the NSTX control system and the legacy Power Conversion link (PCLINK) used for communicating with the PPPL power supplies (first used for TFTR). Additionally a module has been built for communicating with the switching power amplifiers (SPA) recently installed on NSTX. In addition tomore » the hardware developments, the control software [D. Mastrovito, Fusion Eng. And Design 71 65 (2004)] on the NSTX control system has been upgraded. The control computer is an eight processor (8x333MHz G4) built by Sky Computers (Helmsford, MA). The device driver software for the hardware described above will be discussed, as well as the new control algorithms that have been developed to control the switching power supplies for RWM control. An important initial task in RWM feedback is to develop a reliable mode detection algorithm.« less

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
842395
Report Number(s):
PPPL-4092
TRN: US0503267
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALGORITHMS; COMPUTERS; CONTROL SYSTEMS; DATA ACQUISITION; DATA ACQUISITION SYSTEMS; DETECTION; DIGITIZERS; FEEDBACK; FERRON; PHYSICS; POWER AMPLIFIERS; POWER SUPPLIES; SHAPE; Spherical Torus; Tokamaks, NSTX; Plasma Control

Citation Formats

Gates, D A, Ferron, J R, Bell, M, Gibney, T, Johnson, R, Marsala, R J, Mastrovito, D, Menard, J E, Mueller, D, Penaflor, B, and Stevenson, T. Status of the Control System on the National Spherical Torus Experiment (NSTX). United States: N. p., 2005. Web. doi:10.2172/842395.
Gates, D A, Ferron, J R, Bell, M, Gibney, T, Johnson, R, Marsala, R J, Mastrovito, D, Menard, J E, Mueller, D, Penaflor, B, & Stevenson, T. Status of the Control System on the National Spherical Torus Experiment (NSTX). United States. https://doi.org/10.2172/842395
Gates, D A, Ferron, J R, Bell, M, Gibney, T, Johnson, R, Marsala, R J, Mastrovito, D, Menard, J E, Mueller, D, Penaflor, B, and Stevenson, T. Fri . "Status of the Control System on the National Spherical Torus Experiment (NSTX)". United States. https://doi.org/10.2172/842395. https://www.osti.gov/servlets/purl/842395.
@article{osti_842395,
title = {Status of the Control System on the National Spherical Torus Experiment (NSTX)},
author = {Gates, D A and Ferron, J R and Bell, M and Gibney, T and Johnson, R and Marsala, R J and Mastrovito, D and Menard, J E and Mueller, D and Penaflor, B and Stevenson, T},
abstractNote = {In 2003, the NSTX plasma control system was used for plasma shape control using real-time equilibrium reconstruction (using the rtEFIT code - J. Ferron, et al., Nucl. Fusion 38 1055 (1998)). rtEFIT is now in routine use for plasma boundary control [D. A. Gates, et al., submitted to Nuclear Fusion (2005)]. More recently, the system has been upgraded to support feedback control of the resistive wall mode (RWM). This paper describes the hardware and software improvements that were made in support of these physics requirements. The real-time data acquisition system now acquires 352 channels of data at 5kHz for each NSTX plasma discharge. The latency for the data acquisition, which uses the FPDP (Front Panel Data Port) protocol, is measured to be {approx}8 microseconds. A Stand-Alone digitizer (SAD), designed at PPPL, along with an FPDP Input multiplexing module (FIMM) allows for simple modular upgrades. An interface module was built to interface between the FPDP output of the NSTX control system and the legacy Power Conversion link (PCLINK) used for communicating with the PPPL power supplies (first used for TFTR). Additionally a module has been built for communicating with the switching power amplifiers (SPA) recently installed on NSTX. In addition to the hardware developments, the control software [D. Mastrovito, Fusion Eng. And Design 71 65 (2004)] on the NSTX control system has been upgraded. The control computer is an eight processor (8x333MHz G4) built by Sky Computers (Helmsford, MA). The device driver software for the hardware described above will be discussed, as well as the new control algorithms that have been developed to control the switching power supplies for RWM control. An important initial task in RWM feedback is to develop a reliable mode detection algorithm.},
doi = {10.2172/842395},
url = {https://www.osti.gov/biblio/842395}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2005},
month = {8}
}