1,720,994 research outputs found
Test results for triple-modulation radar electronics with improved range disambiguation
No full textThe In Vessel Viewing System (IVVS) is an optical radar with sub milimetrical resolution that will be used for imaging and metrology pourposes in ITER. The electronics of the system is based on a Digital Radar Electronics developed in ENEA Frascati laboratories during the past years. Until the present study, the system was based on amplitude modulation technique having double-modulation frequency. The power of the laser is sinusoidally modulated and the distance of the points scanned by the laser beam is obtained measuring the phase difference between outgoing and echo signals. Recently a triple-modulation radar electronics version and an algorithm able to solve the range disambiguation were developed. The aim of the upgrade was the increase of the robustness in the range disambiguation. The paper briefly describes the updates carried out on the Digital Radar Electronics and extensively the test results obtained by comparing the performance of the triple modulation versus the double modulation techniques. © 2015 Elsevier B.V. All rights reserved
Fully digital intensity modulated LIDAR
No full textIn several applications, such as collision avoidance, it is necessary to have a system able to rapidly detect the simultaneous presence of different obstacles. In general, these applications do not require high resolution performance, but it is necessary to assure high system reliability also within critical scenarios, as in the case of partially transparent atmosphere or environment in presence of multiple objects (implying multiple echoes having different delay times.) This paper describes the algorithm, the architecture and the implementation of a digital Light Detection and Ranging (LIDAR) system based on a chirped optical carrier. This technique provides some advantages compared to the pulsed approach, primarily the reduction of the peak power of the laser. In the proposed architecture all the algorithms for signal processing are implemented using digital hardware. In this way, some specific advantages are obtained: improved detection performance (larger dynamics, range and resolution), capability of detecting multiple obstacles having different echoes amplitude, reduction of the noise effects, reduction of the costs, size and weight of the resulting equipment. The improvement provided by this fully digital solution is potentially useful in different applications such as: collision avoidance systems, 3D mapping of environments and, in general, remote sensing systems which need wide distance and dynamics. © 2016 China Ordnance Societ
Design for the upgrade of the Fast Sequence Control for Frascati Tokamak Upgrade
No full textIn ENEA Frascati research centre an experimental fusion machine called Frascati Tokamak Upgrade (FTU) is in operation since 1990. During the experimental activity, the automatic control and synchronization of many plants are required. The FTU control system [1] includes many sub-systems having different roles [2, 3]. In particular, a Fast Sequence Control (FSC) hardware is necessary to drive the tokamak power plants and to detect the errors in the fast control sequence during the plasma discharge. The FSC system was designed and realized in 1980s and is still in operation. Due to the obsolescence of some hardware components, a new project for the FSC Upgrade (FSCU) has been started. The project includes a new architecture based on up-to-date commercial hardware and dedicated firmware and software. In the present paper the architecture and the functions of the Fast Sequence Control - Upgrade system is described, along with the main differences between the two systems. © 2015 IEEE
Instrumentation, control and data acquisition system with multiple configurations for test in nuclear environment
No full textThe In-Vessel Viewing System is a 3D laser scanning system which will be used to inspect the blanket first wall in ITER. To make the IVVS probe design compatible with the harsh environmental conditions present in ITER, a test campaign was performed in 2012-2013 to verify the adequacy of the main components of the IVVS probe. The IVVS components inspected were an optical encoder, passive components and two customized ultrasonic piezoceramic motors that were instrumented with various sensors. A general architecture of the Data Acquisition and Control System (DACS) was defined and then specialized for each test. To be suitable for this test campaign, the DACS had to host various I/O modules and to properly interface the driver of the customized piezo motors, in order to permit the full control of the test and the acquisition of experimental data. This paper presents the instrumentation solutions designed and implemented for different facilities constraints and the related DACS developed in four specialized versions for the described test campaign. © 2015 Elsevier B.V. All rights reserved
FTU bolometer electronic system upgrade
No full textThe FTU (Frascati Tokamak Upgrade) requires a bolometer diagnostic in order to measure the total plasma radiation. The current diagnostic architecture is based on a full analog multichannel AC bolometer system, which uses a carrier frequency amplifier with a synchronous demodulation. Taking into account the technological upgrades in the field of electronics, it was decided to realize an upgrade for the bolometric electronic system by using a hybrid analog/digital implementation. The new system developed at the ENEA Frascati laboratories has many improvements, and mainly a massive system volume reduction, a good measurement linearity and a simplified use. The new hardware system consists of two subsystems: the Bolometer Digital Control and the Bolometer Analog System. The Bolometer Digital Control can control 16 bolometer bridges through the Bolometer Analog System. The Bolometer Digital Control, based on the FPGA architecture, is connected via Ethernet with a PC; therefore, it can receive commands settings from the PC and send the stream of bolometric measurements in real time to the PC. In order to solve the cross-talk between the bridges and the cables, each of the four bridges in the bolometer head receives a different synthesized excitation frequency. Since the system is fully controlled by a PC GUI (Graphic User Interface), it is very user friendly. Moreover, some useful features have been developed, such as: auto off-set correction, bridge amplitude regulation, software gain setting, real time visualization, frequency excitation selection and noise spectrum analyzer embedded function. In this paper, the hardware and software system architectures are described and some tests of the developed system are presented, with a related statistical analysis. © 2013 Euratom-ENEA Association sulla Fusione
Basic concepts and implementation strategy of the plasma discharge command sequencer for FTU Tokamak
No full textThe plasma discharge phase of Frascati Tokamak Upgrade (FTU) is driven by the dedicated system FSC (Fast Sequence Control), which has been developed in order to send all the necessary commands to the different power plants, feeding the toroidal and poloidal coils during the plasma discharge, meanwhile controlling the correct outcome and recording all the events with time resolution of the order of 20 μs. In case of incorrect execution of the sequence the system is able to safely shutdown the plants and the plasma pulse. The FSC system has been recently upgraded porting it to an up to date off the shelf hardware platform, taking thus the opportunity to revise and update the basic concepts of the system and to increase its flexibility in view of possible applications to future fusion machines. The system is equipped with an integrated configurator and a custom sequence programming language allowing the user to program the sequences by linking the actuation times of the commands and of the state verifications each other or to global time parameters. A dedicated compilator performs the compilation of the sequence generating the binary files that are then loaded and implemented by the FSC hardware
Parallel hardware implementation of RADAR electronics equipment for a LASER inspection system
No full textAn amplitude modulated laser radar has been developed by the Italian Agency for New Technologies, Energy and the Environment for periodic in-vessel inspection in large fusion machines (International Thermonuclear Experimental Reactor). The system is able to obtain a complete three-dimensional mapping of the in-vessel surface. A first digital signal processing system was developed to modulate the laser beam and to detect both the amplitude of the backscattered light and the phase difference between it and the modulation signal. This system is based on commercial digital receiver and parallel digital signal processing boards on a VME bus. It reaches a speed of 100 K measures/s, showing good accuracy and stability. Starting from this, a further development has been done to increase the speed up to 2.328 M measures/s. Reaching the submicrosecond speed was necessary to implement the mathematical algorithm in a highly parallel hardware architecture using a field programmable gate array (FPGA). Based on the good results of the previously developed system, it was decided to maintain the same acquisition front-end though using the last release of analog-to-digital converters, to increase the operating frequency from 80 up to 200 MHz. The software algorithm previously used was completely redesigned and optimized to be used in the FPGA hardware architecture
A plasma discharge fast control system for large fusion reactors
No full textIn ENEA Frascati research centre an experimental fusion machine called Frascati Tokamak Upgrade (FTU) is in operation since 1990. The plasma discharge phase of FTU is driven by the dedicated system FSC-U (Fast Sequence Control upgraded), which has been developed in order to send all the necessary commands to the power plants, feeding the toroidal and poloidal coils during the plasma discharge, meanwhile controlling the correct outcome and recording all the events with time resolution of the order of 20 microseconds. In case of incorrect execution of the sequence the system is able to safely shutdown the plants and the plasma pulse. The present FSC-U system is based on an up to date, off the shelf, hardware platform, and it is equipped with an integrated configurator and a custom command and control sequence programming language, allowing the user to program the sequences by linking the execution times of the commands and of the state verifications each other or to global time parameters. The FSC-U system has been tailored to the I/O FTU needs and time scale, but was conceived with the aim of more powerful up-grades. Now is well in progress a design phase in order to extend the system, increasing of many times the system IO capability and, above all, reaching time resolution of one microsecond. The FSC-U system is a command sequencer that include also some functions and concepts of the interlock and protection system, in the new design this functionality was further enhanced in order to comply with the more demanding applications of the large fusion reactors. © 2017 IEEE
Fully-digital low-frequency lock-in amplifier for photoluminescence measurements
Full text linkLock-in amplifiers, used in several experimental physics applications, are instruments performing quadrature demodulation, which is useful when signals are affected by much noise. Generally, commercially-available lock-in amplifiers are very accurate, but expensive, especially if their operating range includes radiofrequencies. In many applications, high precision is not necessary for the measurements, but it is preferable to have low-cost, low-weight, compactness and a user-friendly graphical unit interface. In this paper, we describe a new fully-digital low-frequency lock-in amplifier developed at ENEA C.R. Frascati Laboratories for photoluminescence experiments based on an innovative low-cost architecture and processing algorithms. The hardware, firmware and software developed for the whole photoluminescence measurement set-up is presented. The present lock-in was first characterized with synthetic electrical sine wave signals and white noise. A dynamic reserve of 43 dB and a noise figure in the range of 25–44 dB were estimated. These results show compatibility with several measurement applications, such as photoluminescence, and the adequacy of the resolutions with respect to the hardware costs. Finally, preliminary results of photoluminescence measurements are presented
Erosion evaluation capability of the IVVS for ITER applications
No full textIn ITER it is foreseen the use of the In Vessel Viewing System (IVVS), whose scanning head is a 3D laser imaging system able to obtain high-resolution intensity and range images in hostile environments. The IVVS will be permanently installed into a port extension, therefore it has to be compliant with ITER primary vacuum requirements. In the frame of a Fusion for Energy Grant, an investigation of the expected IVVS metrology performances was required to evaluate the device capability to detect erosions on ITER first wall and divertor and to estimate the amount of eroded material. In ENEA Frascati laboratories, an IVVS probe prototype was developed along with a method and a computational procedure applied to a reference erosion plate target simulating ITER vessel components and their possible erosions. Experimental tests were carried out by this system performing several scans of the reference target with different incidence angles, estimating the eroded volume and comparing this volume with its true value. A dedicated study has been also done by changing the power of the laser source; a discussion about the quality of the 3D laser images is reported. The main results obtained during laboratory tests and data processing are presented and discussed. © 2014 EURATOM-ENEA Association
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