Technical Report. ICRH DAC Software Modification for Aditya Experiment Requirements

Transcription

1 Technical Report ICRH DAC Software Modification for Aditya Experiment Requirements Ramesh Joshi 1, H M Jadav, Manoj Parihar, B R Kadia, K M Parmar, A Varia, Gayatri Ashok, Y S S Srinivas, Sunil Kumar & S.V. Kulkarni 1 rjoshi@ipr.res.in INSTITUTE FOR PLASMA RESEARCH, NEAR BHAT VILLAGE, GANDHINAGAR INDIA

2 Index: Sr. No. Title Page. No Abstract Introduction. 1 2 ICRH DAC. 2 (i) VME Components.. 3 (ii) DAC Software Modifications and changes. 4 4 VME modifications. 4 a. Integration analog input modules... 4 b. Pooling mode acquisition and monitoring.. 5 c. Multiple analog pulses with different duty cycle 6 d.analog pulse with slow rise and decay e. DAC controlled RF attenuator integration. 7 5 User interface client modifications... 9 a. User interface modifications for pooling mode operation. 9 b. Changes according to generate analog pulses with rise and decay 9 c. Integrated updated calibration with existing DAC d. EPICS prototype integration with ICRH DAC Conclusion References... 13

3 Abstract We have performed several physics experiments like heating, wall conditioning, density mitigation and disruptions on tokamak Aditya with indigenously developed Ion Cyclotron Resonance Heating (ICRH) system [1]. The VME based ICRH Data Acquisition Control system (DAC) has been used for these experiments. There are several changes and modifications performed for different experiments. This paper presents recent changes and modification carried out in ICRH DAC software. ICRH heating experiment demands variable duty cycle pulses, rise and decay time which is used for pulse mode operation. RF attenuator has been introduced for control of RF with different shapes and amplitudes of pulses for control during RF heating experimental pulse and different level of power used for plasma disruption. Decay with RF shot is used to control massive rise of voltage at the end of pulse for high voltage power supplies. VME based data acquisition cards have been replaced with new analog input modules. Analog input modules (IP320, IP330) have been procured and driver program is developed to integrate with existing system. Finally made arrangement of small multiple pulses for longer duration and long continuous pulses for wall conditioning experiment. VME system has been triggered using external trigger from main control system. It may delay sometimes so it has been put in polling mode by which it continuous monitoring and control while waiting for trigger. We ensure deterministic and failsafe operation needed for tokamak testing and operation with each and every components. Several encouraging results have been achieved and published with above mentioned modifications. 1. Introduction: ADITYA is a medium size tokamak with major radius 0.75 m and minor radius of 0.25 m, with toroidal magnetic field up to 1.5 T and has circular plasma in hydrogen gas. There are different methods developed for producing pre-ionization and second harmonic heating of plasma using fast wave antenna is an established technique for ion cyclotron heating of tokamak plasma [2]. The indigenously developed ICRH system is installed on ADITYA having 1 MW RF generator in the frequency range of MHz, transmission line with matching system, vacuum interface and fast wave poloidal type antenna with Faraday shield [3,4]. This report describes the recent ICRH DAC modifications in order to carry out different experiments on tokamak ADITYA using the ICRH system. The experiments are carried out to have plasma heating at second harmonic using 1 MW system at 24.8 MHz, disruption mitigation using RF power from poloidal fast wave antenna and also wall conditioning in presence of toroidal magnetic field. To analyze the system performance it is essential to monitor, acquire different system parameters along with an interlocking system to operate the system in failsafe manner. ICRH system has its own data acquisition and control system to execute the task of data archiving, monitoring, interlocking and control. The analysis of acquired data takes place in offline mode. 1

4 The programming on the VME system includes card driver programming, system integration programming for the ICRH system operation & control. The real time controlling application software modules are developed on the VME hardware on VxWorks RTOS Tornado IDE environment in C++ with networking and Board Support Package libraries. It also includes socket programming for graphical user interface (client) in communication with VME server. Various monitoring and control loops are running on VME server as per requirements with system synchronization. DAC client includes graphical user interface for operating the whole system remotely. The Graphical User Interface is developed in TCL/TK on Linux platform on PC for online monitoring and interactive control. It provides multithreading facility by which user can monitor and acquire the data at the same time. 2. ICRH DAC ICRH Generator DAC controls all the HVDC power supplies, through signals like ON, OFF, raise, lower, start/stop etc. Output voltage and current of HVDC power supplies for 2kW, 20kW, 200kW and 1500kW stages are monitored during the RF pulse and can be graphically displayed for analysis. The 200 kw and 1500 kw stages filament, screen grid and control grid power supplies and are remotely operated by start/stop signal and their status and all the parameters are acquired as well as displayed in real time. Figure-1 shows the block diagram of ICRH DAC connected with ICRH subsystems using signal conditioning with RTOS based DAC hardware. ICRH DAC is used for control and monitoring for 2 kw, 20 kw and 200 kw and 1.5 MW RF amplifier stages respectively. Each lower stage amplifier output is fed to next higher stage amplifier. ICRH system consists of different power supplies for each stage. First two stages need single high voltage power supplies and 200 kw stage onwards each stage needs four power supplies named plate, screen grid, filament and control grid. Normally in the amplifier stages of 2 kw and above, RF tubes like triodes and tetrodes are used which need many power supplies like screen grid, control grid, plate power supply and filament power supply. For proper operation of amplifier stage one needs to follow proper switching on/off and emergency switching off sequence. The amplifier stages above 2 kw level also needs proper cooling and one needs to follow certain sequence and have interlock with cooling during operation. Normally complete ICRH system is controlled, monitored and the data is acquired with the help of real time operating systems and fast computers like VMEs to control, monitor & interlock signals of high voltage power supplies for operating various RF Amplifier stages in ICRH system. 2

5 Fig-1 Block diagram of ICRH DAC (i) VME Components VME Hardware cards used are, SBS VG4 (400MHz) Processor board based on Motorola PowerPC VMIVME 2528 Digital I/O card AVME 9660 Carrier Board. IP 480 Timer/Counter module. IP 220 Analog O/P module. IP 330 Analog I/P modules. Analog Input Cards Digital I/O (Fiber Optic Tx/Rx Card) (ii) DAC Software VME Control Programming: The software programming on the VME system includes card driver programming, system integration programming for the ICRH system operation & control. It also includes socket programming for graphical user interface (client) in communication with VME server. Various monitoring and control loops are running on VME server as per requirements with system synchronization. The real time controlling application software modules are developed on the VME hardware on vxworks RTOS Tornado environment in C/C++ with networking and board support package (BSP) libraries. The Graphical User Interface is developed in TCL/TK on Fedora core platform for online monitoring and interactive control. The acquired data is archived on Network file system, which is based on binary files and stored in database server. The DAC software is based on the fundamentals of the socket programming. The client software communicates with the VME using TCP socket and acquires the monitoring 3

6 packets and acquisition packets and sends the control signals to the VME to control the physical subsystem. DAC Software Client: DAC Client includes graphical user interface for operating the whole system remotely. TCL/TK is used as graphical toolkit to make user interface for client system. Recent version provides multithreading facility by which user can monitor and acquire the data at the same time. Data Acquisition: MDS+ based data acquisition module has been implemented, which is directory based data archival system. VME software can acquire data at the rate of 1ms for seconds operation. The data has been stored in MDS+ in tree structure, which can be evaluated with visualization tool provided with database system. Data Analysis: Jscope is used for data analysis software module implemented for off-line (post shot) analysis of acquired data. This is Java based tool to represent the tree based data into graphical manner for further evaluation and analysis purpose. 3. Modifications and changes: Following are the major changes and modifications carried out with ICRH DAC, 1. VME modifications a. Integration analog input modules b. Polling mode acquisition and monitoring c. Multiple analog pulses with different duty cycle for wall conditioning experiment d. Analog pulse with slow rise and decay e. DAC controlled RF attenuator integration 2. User interface client modifications a. User interface modifications for polling mode operation b. Changes to generate analog pulses with rise and decay pulses c. Integrated updated calibration with existing DAC d. EPICS prototype integration with ICRH DAC 4. VME modifications: a. Integration analog input modules Analog input modules named IP320 and IP330 (industrial pack module by Acromag) device drivers have been developed for VME based DAC software for ICRH system. IP320 module supports 12 bit resolution, 20 differential or 40 single ended inputs and IP330 module supports 16 bit resolution, 16 differential or 32 single ended inputs. ICRH DAC has been used to control, monitor and store data for MHz, 1 MW RF amplifier stages and connected power supplies. 4

7 The existing system was using two avme9325 analog input modules but there are random problems in module has been detected during operation as those are more than 20 years old which are not available in market for procurement. So it has been decided to modify the existing acquisition module with compatible module which should work with existing VME hardware and support software. Analog input IP modules drivers have been developed with Motorola processor having power pc gnu cross compilation. These modules have been used to acquire data (at >=1kHz) for 2 kw, 20 kw, 200 kw and 1.5 MW RF amplifier stages and connected power supplies during RF shot. b. Polling mode acquisition and monitoring Aditya experiment requires external trigger for Aditya in order to deliver RF power for required duration. ICRH DAC software has to wait till the trigger comes. In existing system it was suspend the system monitoring till the trigger comes from Aditya control system and the monitoring and status will not be available for that time duration. Polling mode operation has been established with ICRH DAC using IP480 timer card in synchronous with digital I/O module by which during the wait time of Aditya trigger system will monitor and gives all status of power supplies. Fig-2: Multiple analog pulses with different duty cycle within digital pulse 5

8 c. Multiple analog pulses with different duty cycle Aditya wall conditioning experiment requires multiple pulses for long duration. ICRH VME software has been modified in order to provide multiple pulses for any duration demanded by ICRH experiment [5]. In these pulses main digital pulse is divided into multiple pulses with different duty cycles. With different amplitude of pulses RF power can be vary as per experimental requirement. d. Analog pulse with slow rise and decay Fig-3: Analog pulses with decay within digital pulse There are two different requirements of this kind of pulse. In first phase decay with end of the pulse has been introduced which gives 10% decay in each ms at the end of the pulse irrespective to amplitude of the analog pulse. High voltage power supply for RF amplifier stage has been increased at the end of RF pulse. Using decay in analog pulse at the end of pulse solve issue of damage with high voltage power supply during ICRH operation. In second phase the Aditya experiment needs slow rise and slow off RF power. This requirement has been satisfied using analog pulse with slow rise and decay for experiment. 6

9 Fig-4: Demonstration of controlled voltage rise at the end of pulse using decay e. DAC controlled RF attenuator integration Fig-5: Analog pulses with decay within digital pulse 7

10 The earlier control system software is based upon the pulse operation of RF source using digital pulse generated by VME control system. Recently we modified the software to generate multiple analog pulses with different duty cycles in master digital pulse for data acquisition and control system for steady state operation of RF Generator in Aditya [6]. Fig. 6(a) Block Diagram of the existing DAC system Fig. 6(b) Block Diagram of the modified DAC system Figure 6(a) shows the schematic of the mechanism to make digital pulses generated by VME subsystem for triggering function generator to switch on RF, which was existing setup used by DAC system. VME hardware cards like ip220, vmivme2528 and ip480 are required to generate pulses in synchronous manner. Figure 6(b) shows the schematic of the mechanism to make analog pulses to be generated using voltage variable attenuator in path of VME subsystem. VME hardware cards like ip220, vmivme2528 and ip480 are used to generate pulses in synchronous manner. System will generate two analog pulses in slave mode with master digital pulse generated using VME hardware. 8

11 5. User interface client modifications a. User interface modifications for polling mode operation There are several modifications and changes have been integrated with existing user interface client program. Figure-7 shows the shot panel for ICRH DAC software. There are 9 tabs included in software for monitoring and control. First upper panel shows different power supplies and monitoring of each power supply voltage and current. Second upper panel shows shot parameters for digital as well as analog pulse parameters. There are several shot option buttons for applying shot like dummy load shot with lab dummy load, vaccum shot with tokamak, and external triggered shot for Aditya. Below side shows log messages for DAC operation. DAC is waiting for trigger from tokamak control panel log message shows waiting for shot. After applying shot successfully it shows shot completed, please acquire data to store on hard disk. b. Changes according to generate analog pulses with rise and decay Fig-7: Modified user interface screen for Aditya experiment 9

12 Different duty cycles and different analog voltages parameters has to be set to generate corresponding voltage, which will be applied to voltage variable attenuator. User Interface is developed for parameter setting for RF shot and is shown in Figure-7. It also indicates RF output analog pulse according to input parameters for ontime-1, analog voltage-1, offtime and analog voltage-2. c. Updated calibration with integration existing DAC Fig-8: Calibration table with smoothing values for each channel Figure-8 shows calibrated voltage and current signals for each power supply with calibrated graph. Recently some of the power supplies have been changes or modified as per experimental requirement. So updated linear calibrations have been added with existing application and applied for each signals. 10

13 Fig-9 CSS screen shot for 2 kw and 20 kw monitoring and control system d. EPICS prototype integration with ICRH DAC Synchronization of DAC could be possible with EPICS (Experimental Physics and Industrial Control System) process variables, which broadcast and describe itself in Ethernet network. The existing system uses the TCP/IP Ethernet network for communication with DAC clients. EPICS provides channel access protocol layers which broadcast required process variable on periodic time interval which are available on network for communication. The prototype program is developed for real-time state parameters transmission and storage, dynamic graphical display, modification of the interactive system and synchronization [7]. 11

14 Fig-10 CSS shot panel ICRH DAC Fig-11 EPICS process variable broadcasting screen 12

15 Figure-9 shows Control System Studio (CSS) screen for 2 kw and 20 kw power supply monitoring and control screen. This prototype screen has been developed using open source eclipse based toolkit compatible with EPICS process variable communications. Figure-10 shows the shot panel screen using same toolkit. Power supply status and monitoring parameter for each power supplies have been shown in that screen. 200 kw and 1500 kw RF amplifier stage power monitoring screen have also been included in shot panel. Figure-11 shows EPICS broadcasting screen in windows operating system. EPICS provides all analog and digital signals as process variable broadcasting using channel access protocol. These process variable available on network on periodic update of broadcasted process variables. Python scripts have been used for variable update on periodic update of signals. DAC synchronization as well as slow control can be easily implemented using EPICS. Conclusion: Several modifications and changes have been successfully incorporated with existing DAC system for various Aditya experiments. Recent successful experiments prove reliability and scalability of ICRH DAC. ICRH DAC is ready for future experimental changes and modifications like RHVPS integration, Aditya Upgrade and other upcoming changes. References: 1. S V Kulkarni et. Al, Recent ICRH-Wall Conditioning, Second Harmonic Heating and Disruption Mitigation Experiments using ICRH system in Tokamak ADITYA, IAEA Fusion Energy Conference Engineering design report (EDR) of ICRH-SST1 SST RF Group 3. Durodie F., Veriver M. European physics society (EPS), 1992,p D. Bora, Sunil Kumar, Raj Singh, K. Sathyanarayana, S.V. Kulkarni, A. Mukherjee. & RF group. Cyclotron resonance heating systems for SST-1 Published in Nuclear Fusion:Voloume 46 Number 3 March Ramesh Joshi 1, Manoj Singh, H. M. Jadav, Kishor Misra, S. V. Kulkarni & ICRH-RF Group. Generation of multiple analog pulses with different duty cycles within VME control system for ICRH Aditya system Presented in 23 rd National Symposium on Plasma & technology 6. MANOJ SINGH, H. M. JADAV, RAMESH JOSHI, SUNIL KUMAR, SHRINIVAS YSS, S.V. KULKARNI and ICRH-RF GROUP 13

16 DAC CONTROLLED VOLTAGE VARIABLE RF ATTENUATOR FOR GENERATION RF PULSES OF DIFFERENT SHAPES AND AMPLITUDES FOR ICRH SYSTEM, Technical report [ IPR/TR-292/2014 JUNE-2014] 7. Ramesh Joshi, Manoj Singh, S. V. Kulkarni & Kiran Trivedi Benchmarking and Analysis of the User-Perceived Performance of EPICS based ICRH DAC [IESA International Conference on Industrial Engineering Science and Applications , 2-4 April 2014 ] 14