A.P. Rodrigues

ATCA/xTCA-based hardware for control and data acquisition on Nuclear Fusion fast control plant systems

In contemporary control and data acquisition systems for Nuclear Fusion devices, the galloping need for high channel density and real-time multi-input-multi-output (MIMO) support gave rise to a new generation of hardware architecture based on the Advanced Telecommunications Computing Architecture (ATCA) specification. In addition, ATCA successfully delivered solutions in other sensitive issues such as form-factor component area, power dissipation and redundancy, complying with the high complexity and security required for such systems. Experience has showed, however, that due to its aforementioned complexity, such hardware devices can yield to a lengthy development. Furthermore, the ATCA specification is, as yet, somewhat undefined for instrumentation applications, more so within the specificities of Plasma Physics applied devices. The entitled “xTCA” specification is currently being developed for those purposes. Based on the ATCA itself, it will define new functionalities that standardize and facilitate hardware development for device operation in a Fusion control plant environment - most notably, dedicated timing and input-output (IO) port assignment on the Rear Transition Module (RTM). The prototype hereby presented is an xTCA Peripheral Component Interface (PCIe) switch Advanced Mezzanine Card (AMC) carrier blade. The device serves as a hub, as to control and handle I/O data from its parent nodes existing within the same xTCA shelf through its proprietary fabric channels in dual-star topology. Parent node blades, under development, are equally linked through xTCAs agnostic fabric in full-mesh topology, as to attain system MIMO functionality from all I/O endpoints. The switch blade carries up to four AMC modules, adding up to modularity and versatility. This allows for a much more independent and speedier hardware development, as dedicated AMC modules, such as data processing and storage devices, can be simultaneously projected. Commercial off-the-shelf (COTS) AMC products are readily available and may also be immediately integrated in the system.

A high performance real-time plasma control and event detection DSP based VME system

This paper describes the digital signal processors module of a high performance system, specially designed for real-time plasma control and event detection on the next generation fusion experiments with long duration discharges. The system is composed of a commercial CPU board and several on-site developed intelligent modules inserted in the same VME crate.

Digital control system for the TCV tokamak

A new digital feedback control system has been developed, integrated and used successfully to control the TCV plasma. The system is designed to be modular, distributed, and easily expandable, accommodating hundreds of diagnostic inputs and actuator outputs. It offers the possibility to design advanced control algorithms using more information on the plasma state, as well as the ability to control all TCV actuators, including PF coils, gas valves, the gyrotron powers and launcher angles of the ECRH/ECCD system, as well as diagnostic triggering signals. The system consists of multiple PC nodes connected to a sharing memory network. The control algorithms are programmed as block diagrams in Simulink. Using Embedded Coder, the C code is generated automatically from the Simulink model, then compiled into a Linux shared library (“.so” file) and copied to target nodes. When the TCV discharge is progressing, an application on each node is executed and dynamically loads the shared library at runtime. During the real time process, to dedicate the whole CPU performance for the algorithms, all interrupts to the CPU on each node are suspended. Since its inception, the new digital control system has enabled a multitude of plasma control applications, ranging from basic experiments of coil current and density control to advanced experiments of MHD and plasma profile control, as well as real-time plasma transport simulations. This paper presents the architecture of the new control system and its integration into the TCV plant.

Engineering design of ITER prototype Fast Plant System Controller

The ITER control, data access and communication (CODAC) design team identified the need for two types of plant systems. A slow control plant system is based on industrial automation technology with maximum sampling rates below 100 Hz, and a fast control plant system is based on embedded technology with higher sampling rates and more stringent real-time requirements than that required for slow controllers. The latter is applicable to diagnostics and plant systems in closed-control loops whose cycle times are below 1 ms. Fast controllers will be dedicated industrial controllers with the ability to supervise other fast and/or slow controllers, interface to actuators and sensors and, if necessary, high performance networks. Two prototypes of a fast plant system controller specialized for data acquisition and constrained by ITER technological choices are being built using two different form factors. This prototyping activity contributes to the Plant Control Design Handbook effort of standardization, specifically regarding fast controller characteristics. Envisaging a general purpose fast controller design, diagnostic use cases with specific requirements were analyzed and will be presented along with the interface with CODAC and sensors. The requirements and constraints that real-time plasma control imposes on the design were also taken into consideration. Functional specifications and technology neutral architecture, together with its implications on the engineering design, were considered. The detailed engineering design compliant with ITER standards was performed and will be discussed in detail. Emphasis will be given to the integration of the controller in the standard CODAC environment. Requirements for the EPICS IOC providing the interface to the outside world, the prototype decisions on form factor, real-time operating system, and high-performance networks will also be discussed, as well as the requirements for data streaming to CODAC for visualization and archiving.

Adaptive Counting Rule for Cooperative Spectrum Sensing Under Correlated Environments

Spectrum sensing is the cognitive radio mechanism that enables spectrum awareness. It has been shown in the literature that spectrum sensing performance can be greatly improved through the use of cooperative sensing schemes. This paper considers and proposes a data fusion based cooperative spectrum sensing scheme based on data fusion, where an adaptive counting rule is used to implement the data fusion. The proposed scheme is evaluated against other common counting rules (e.g., 1-out-of-c and c-out-of-c) found in the literature and the optimum counting rule, while under different correlation conditions. The impact of correlation on the performance of the considered counting rules is then studied. It is concluded that the proposed adaptive counting rule detection performance reaches in some cases the one of the optimum counting rule, and therefore it adapts to the correlation conditions which the network nodes are experiencing.

On-site developed components for control and data acquisition on next generation fusion devices

Publisher Summary This chapter discusses the main requirements, principles and technical issues to be taken into account in the conceptual design of the control and data acquisition systems of new fusion experiments. The control and data acquisition system of a new generation fusion device should be conceived in a distributed, integrated, hierarchical, manufacturing independent, and user-friendly approach, taking advantage of the most recent improvements in networking, front-end processing, and database management. Data acquisition is performed by several dedicated subsystems designed in a function oriented structure and linked by fast networks. This architecture allows to develop the subsystems independently, to minimize the data traffic in the network, and to increase the system safety. It also provides upgrading capacity to meet new experimental requirements during the life of the experiment and flexibility to include new technologies.

Digital Control System for the TCV Tokamak

This paper presents the hardware and software approach to replacing the current analogue linear feedback system on the TCV Tokamak with a DSP based system to allow for non-linear control. After preliminary combination, over 120 control signals are reduced to 32 parameters which enter an array of 32 DSP processors each of which is passed the complete parameter set. Apart from data transfer and storage, each DSP will run its separate control algorithm with a repetition rate up to 20 kHz. A separate DSP board is dedicated to the plasma vertical control which requires a 200 kHz feedback rate. This paper presents the hardware and the software that is being designed to put this control block in the hands of non DSP-expert physics users

Real-time multi-DSP based VME system for feedback control on the TCV Tokamak

This paper describes a real-time pulse height analysis diagnostic for feedback control of the TCV plasma. The implementation of this diagnostic is based on a new generation X-ray detector with high resolution and count rate, an in-house developed VME intelligent module, with parallel processing capabilities provided by four Digital Signal Processors, and several digital signal processing algorithms. Results show that a value of the electron temperature (T/sub e/) can be calculated in approximately 100 ms, thus providing a twenty-value T/sub e/ profile during a TCV discharge. The time resolution might be increased by improving the X-ray detecting system and/or the processing procedures.

Unified propagation model for Wi-Fi, UMTS and WiMAX planning in mixed scenarios

This paper presents an unified and empirical propagation model to obtain the received power in mixed scenarios, with outdoor and indoor environments, or in a scenario with only one kind of environment, either for an urban, sub-urban or rural scenario, with or without vegetation. This unified model is called the Lisbon University Institute (LUI) one and can be included into planning tools for wireless communication systems. The developed model is suitable for Path Loss prediction in mobile, as well as fixed wireless network systems, e.g., Wireless Fidelity, Universal Mobile Telecommunications System and Worldwide Interoperability for Microwave Access, considering Line-of-Sight or Non-Line-of-Sight propagation conditions.

FPGA Remote Update for Nuclear Environments

In recent years there has been a growing interest to use reconfigurable modules, based on field-programmable gate array (FPGA) devices, in nuclear environments. One of the requirements for these types of modules, when operating in complex future nuclear power experiments, is their remote update capability. The operational needs of pulsed fusion reactors will lead to a large production of very high energy neutrons (MeV range). The current procurement policies for nuclear installations do not allow exposure of electronics to radiation, except following very strict rules. However, considering the “as low as (is) reasonably achievable” (ALARA) principle with respect to human exposure to radiation, the access to cubicles might be restricted, requiring the remote update of FPGA codes. FPGAs are volatile devices, and their programming code is usually stored in dedicated flash memories for proper configuration during module power-on. This paper presents an alternative method for FPGA remote update, capable to store new FPGA codes in inboard Serial Peripheral Interface (SPI) flash memories. The new method, based on the Xilinx Quick Boot application note and adapted to PCIe protocol, was developed with the KC705 Evaluation Kit from Xilinx and successfully tested in the in-house Advanced Mezzanine Card (AMC) prototype, installed on the ATCA-PTSW-AMC4 carrier module from the ITER Fast Plant System Controller catalogue.