A digital long pulse integrator

A prototype digital integrator with very long integration capabilities has been developed and field tested on an inductive magnetic sensor on the DIII-D Tokamak. The integrator is being developed for use on ITER with a pulse length of 1000 s, and has direct applications for other long pulse Tokamaks. Inductive magnetic sensors are routinely used on existing Tokamaks, are well understood, and are extremely robust, however, they require integration of the signal to determine the magnetic field strength. The next generation of Tokamaks, will have pulse lengths of 1000 s or longer, require integrators with drift and noise characteristics compatible with the very long pulse lengths. This paper will discuss the architecture, algorithms, and programming of the Long Pulse Integrator (LPI). Of particular interest are the noise control and the built-in offset correction techniques used in this application

A hybrid digital-analog long pulse integrator

A digital-analog integrator has been developed for use with inductive magnetic sensors in long-pulse tokamaks. Continuous compensation of input offsets is accomplished by alternating analog-to-digital convertor samples from the sensor and a dummy load, while an RC network provides passive integration between samples. Typically a sampling rate of 10 kHz is used. In operational tests on the DIII-D tokamak, digital and analog integration of tokamak data show good agreement. The output drift error during a 1200 s integration interval corresponds to a few percent of the anticipated signal for poloidal field probes in International Thermonuclear Experimental Reactor (ITER), and bench tests suggest that the error can be reduced further

Real time software for the control and monitoring of DIII-D system interlocks

This paper describes the real time, multi-tasking, multi-user software and communications of the E-Power Supply System Integrated Controller (EPSSIC) for the DIII-D tokamak. EPSSIC performs the DIII-D system wide go/no-go determination for the plasma sequencing. This paper discusses the data module handling, task work load balancing, and communications requirements. Operational experience with the new EPSSIC and recent improvements to this system are also described

ACTIVE FILTER HARDWARE DESIGN & CONTROL SYSTEM PERFORMANCE FOR THE DIII-D PLASMA ACTIVE FILTER HARDWARE DESIGN & CONTROL SYSTEM PERFORMANCE FOR THE DIII-D P~S M A Active Filter Hardware Design & Performance for the DIII-D Plasma Control System

Abstract. The digital plasma control system (PCS), currently in operation on the DIII-D tokamak, requires inputs from a large number of sensors. Due to the nature of the digitizers and the relative noisy environment from which these signal are derived, each of the 32 signals must be conditioned via an active filter. Two different types of filters, Chebyshev and Bessel with fixed frequencies: l0OHz Bessel was used for filtering the motional Stark effect diagnostic data. 800 Hz Bessel was designed to filter plasma control data and 1200 Hz Chebyshev is used with closed loop control of choppers. The performance of the plasma control system is greatly influenced by how well the actual filter responses match the software model used in the control system algorithms. This paper addresses the various issues facing the designer in matching the electrical design with the theoretical

Active Filter Hardware Design & Performance for the DIII-D Plasma Control System

OAK-B135 The digital plasma control system (PCS), currently in operation on the DIII-D tokamak, requires inputs from a large number of sensors. Due to the nature of the digitizers and the relative noisy environment from which these signals are derived, each of the 32 signals must be conditioned via an active filter. Two different types of filters, Chebyshev and Bessel with fixed frequencies: 100 Hz Bessel was used for filtering the motional Stark effect diagnostic data. 800 Hz Bessel was designed to filter plasma control data and 1200 Hz Chebyshev is used with closed loop control of choppers. The performance of the plasma control system is greatly influenced by how well the actual filter responses match the software model used in the control system algorithms. This paper addresses the various issues facing the designer in matching the electrical design with the theoretical

A Handheld, Free Roaming, Data Display for DIII-D Diagnostic Data

Standard handheld test instruments such as voltmeters and portable oscilloscopes are useful for making basic measurements necessary for the operation and maintenance of large experiments such as the DIII-D magnetic fusion research facility. Some critical diagnostic information, however, is available only on system computers. Often this diagnostic information is located in computer databases and requires synthesis via computational algorithms to be of practical use to the technician. Unfortunately, this means the data is typically only available via computer screens located at fixed locations. One common way to provide mobile information is to have one operator sit at a console and read the data to the mobile technician via radio. This is inefficient in as much as it requires two people. Even more importantly the operator-to-technician voice link introduces significant delays and errors that may hinder response times. To address these concerns of personnel utilization and efficiency, we have developed a remote display based on an rf-data link that can be carried with a technician as he moves about the facility. This display can provide the technician with any information needed from the stationary database. This paper will discuss the overall architecture as well as the individual modules for the mobile data display. Lessons learned, as well as techniques for improving the usefulness of such systems, will be presented

Early false-belief understanding in traditional non-Western societies

The psychological capacity to recognize that others may hold and act on false beliefs has been proposed to reflect an evolved, species-typical adaptation for social reasoning in humans; however, controversy surrounds the developmental timing and universality of this trait. Cross-cultural studies using elicited-response tasks indicate that the age at which children begin to understand false beliefs ranges from 4 to 7 years across societies, whereas studies using spontaneous-response tasks with Western children indicate that false-belief understanding emerges much earlier, consistent with the hypothesis that false-belief understanding is a psychological adaptation that is universally present in early childhood. To evaluate this hypothesis, we used three spontaneous-response tasks that have revealed early false-belief understanding in the West to test young children in three traditional, non-Western societies: Salar (China), Shuar/Colono (Ecuador) and Yasawan (Fiji). Results were comparable with those from the West, supporting the hypothesis that false-belief understanding reflects an adaptation that is universally present early in development