P. Makijarvi

ITER CODAC status and implementation plan

CODAC (Control, Data Access and Communication) is the central control system responsible for operating the ITER device. CODAC interfaces to more than 160 plant systems containing actuators, sensors and local control. CODAC is responsible for coordinating and orchestrating the operation of these plant systems including plasma feedback control. CODAC is developed by ITER Organization, while plant systems are developed by the seven ITER parties (China, Europe, India, Japan, Korea, Russia and United States). This procurement model poses enormous challenges, has a big impact on architecture design and requires a strong standardization for better integration and future maintenance. In this paper we briefly describe the CODAC conceptual design, elaborate on the actions taken by the CODAC team to move from conceptual to engineering design during the last year and outline the plans ahead.

Present status of the ITER real-time Plasma Control System development

ITER will be the worlds largest magnetic confinement tokamak fusion device and is currently under construction in southern France. The ITER Plasma Control System (PCS) is a fundamental component of the ITER Control, Data Access and Communication system (CODAC). It will control the evolution of all plasma parameters that are necessary to operate ITER throughout all phases of the discharge. The design and implementation of the PCS poses a number of unique challenges. The timescales of phenomena to be controlled spans three orders of magnitude, ranging from a few milliseconds to seconds. Novel control schemes, which have not been implemented at present-day machines need to be developed, and control schemes that are only done as demonstration experiments today will have to become routine. In addition, advances in computing technology and available physics models make the implementation of real-time or faster-than-real-time calculations to forecast and subsequently to avoid disruptions or undesired plasma regimes feasible. A further novel feature is a sophisticated event handling system, which provides a means to deal with plasma related events (such as MIlD instabilities or LH transitions) or component failure. Finally, the schedule for design and implementation poses another unique challenge. The beginning of ITER operation will be in late 2020, but the conceptual design activity has already commenced as required by the on-going development of diagnostics and actuators in the domestic agencies and the need for integration and testing. In this paper, an overview about the functional requirements for the plasma control system will be given. The main focus will be on the requirements and possible options for a real-time framework for ITER and its interfaces to other ITER CODAC systems (networks, other applications, etc.). The limited amount of commissioning time foreseen for plasma control will make extensive testing and validation necessary. This should be done in an environment that is as close to the PCS version running the machine as possible. Furthermore, the integration with an Integrated Modeling Framework will lead to a versatile tool that can also be employed for pulse validation, control system development and testing as well as the development and validation of physics models. An overview of the requirements and possible structure of such an environment will also be presented.

High-performance image acquisition and processing system with MTCA.4

Fast evolution of high-performance cameras in recent years has made them promising tools for observing transient and fast events in large-scale scientific experiments. Complex experiments, such as ITER, take advantage of high-performance imaging system consisting of several fast cameras working in the range of visible and infrared light. The paper presents a first implementation of complete image acquisition system built on the basis of MTCA.4 architecture, which is dedicated for operation with high-resolution fast cameras equipped with Camera Link interface. Image data from the camera are received by the frame grabber card and transmitted to the host via PCIe interface. The modular structure of MTCA.4 architecture allows connecting several cameras to a single MTCA chassis. The system supports precise synchronization with the time reference using Precision Time Protocol (IEEE 1588). The software support for the system includes low-level drivers and API libraries for all components and high-level EPICS-based environment for system control and monitoring.

Baseline architecture of ITER control system

The control system of ITER consists of thousands of computers processing hundreds of thousands of signals. The control system, being the primary tool for operating the machine, shall integrate, control and coordinate all these computers and signals and allow a limited number of staff to operate the machine from a central location with minimum human intervention. The primary functions of the ITER control system are plant control, supervision and coordination, both during experimental pulses and 24/7 continuous operation. The former can be split in three phases; preparation of the experiment by defining all parameters; executing the experiment including distributed feed-back control and finally collecting, archiving, analyzing and presenting all data produced by the experiment. We define the control system as a set of hardware and software components with well defined characteristics. The architecture addresses the organization of these components and their relationship to each other. We distinguish between physical and functional architecture, where the former defines the physical connections and the latter the data flow between components. In this paper, we identify the ITER control system based on the plant breakdown structure. Then, the control system is partitioned into a workable set of bounded subsystems. This partition considers at the same time the completeness and the integration of the subsystems. The components making up subsystems are identified and defined, a naming convention is introduced and the physical networks defined. Special attention is given to timing and real-time communication for distributed control. Finally we discuss baseline technologies for implementing the proposed architecture based on analysis, market surveys, prototyping and benchmarking carried out during the last year.

IEEE 1588 Time Synchronization Board in MTCA.4 Form Factor

Distributed data acquisition and control systems in large-scale scientific experiments, like e.g. ITER, require time synchronization with nanosecond precision. A protocol commonly used for that purpose is the Precise Timing Protocol (PTP), also known as IEEE 1588 standard. It uses the standard Ethernet signalling and protocols and allows obtaining timing accuracy of the order of tens of nanoseconds. The MTCA.4 is gradually becoming the platform of choice for building such systems. Currently there is no commercially available implementation of the PTP receiver on that platform. In this paper, we present a module in the MTCA.4 form factor supporting this standard. The module may be used as a timing receiver providing reference clocks in an MTCA.4 chassis, generating a Pulse Per Second (PPS) signal and allowing generation of triggers and timestamping of events on 8 configurable backplane lines and two front panel connectors. The module is based on the Xilinx Spartan 6 FPGA and thermally stabilized Voltage Controlled Oscillator controlled by the digital-to-analog converter. The board supports standalone operation, without the support from the host operating system, as the entire control algorithm is run on a Microblaze CPU implemented in the FPGA. The software support for the card includes the low-level API in the form of Linux driver, user-mode library, high-level API: ITER Nominal Device Support and EPICS IOC. The device has been tested in the ITER timing distribution network (TCN) with three cascaded PTP-enabled Hirschmann switches and a GPS reference clock source. An RMS synchronization accuracy, measured by direct comparison of the PPS signals, better than 20 ns has been obtained.

ITER prototype fast plant system controller based on ATCA platform

The ITER Fast Plant System Controllers (FPSC) are based on embedded technologies and will be devoted to both data acquisition tasks (sampling rates >1 kSPS) and control purposes in closed-control loops whose cycle times are below 1 ms. Fast Controllers will be dedicated industrial controllers with the ability to: i) supervise other fast and/or slow controllers; ii) interface to actuators and sensors and high performance networks. This contribution presents an FPSC prototype, specialized for data acquisition, based on the ATCA (Advanced Telecommunications Computing Architecture) standard. This prototyping activity contributes to the ITER Plant Control Design Handbook (PCDH) effort of standardization, specifically regarding fast controller characteristics. For the prototype, IPFN is developing a new family of ATCA modules targeting ITER requirements. The modules comprise an AMC carrier/data hub/timing hub compliant with the upcoming ATCA extensions for Physics and a multi-channel with galvanic isolation hot-swappable digitizer designed for serviceability. The design and test of a peer-to-peer communications layer for the implementation of a reflective memory over PCI Express and the design and test of an IEEE-1588 transport layer over a high performance serial link was also performed. In this work, a complete description of the solution is presented as well as the integration of the controller into the standard CODAC environment. The most relevant results of real tests will be addressed, focusing in the benefits and limitations of the applied technologies.

Data archiving system implementation in ITER's CODAC CORE SYSTEM

A new data archiving implementation developed by the CIEMAT-INDRA-SGENIA-UPM Consortium (in alphabetical order) has been fully integrated into ITERs CODAC CORE SYSTEM at the beginning of year 2015. This software includes components on the client and server sides that are responsible for the distribution and archiving of acquired or process-generated data, with important restrictions. On the one side, ITERs high pulse length requires that any data archiving implementation include a steady state archiving mechanism with continuous storage of the data acquired and processed throughout the experiment. On the other side, all these data must be safely archived and continuously available for read systems on the client side in a short time from their acquisition. On the side of client systems, a new software library has been developed with two main goals. The first one is to provide simple and complete data archiving functionality, while the second pursues to implement a continuous and efficient data distribution engine including different data sources as well as a diversity of potential consumer systems. From the server-based perspective, a complete solution has been implemented using the HDF5 files as the underlying data storage technology, while adapting the metadata structures and data access protocols to meet ITERs CODAC requirements.