2015 IEEE INTERNATIONAL CONFERENCE ON ELECTRICAL, COMPUTER AND COMMUNICATION TECHNOLOGIES
Engineering Design of Labview Based Prototype Software Development for 45.6 MHz, 100KW ICRH DAC 1
Aniruddh Mali, 2Ramesh Joshi,2H.M. Jadav, 2S.V. Kulkarni & 3Krupa Mehta 1
2
EC Department, L.D. College of Engineering, Ahmedabad, India High Power ICRH Division, Institute for Plasma Research, Gandhinagar, India 3 U V Patel College of Engineering, Kherva, Gujarat – 384012 1
[email protected] &
[email protected]
Abstract— Ion Cyclotron Resonance Heating (ICRH) Data Acquisition Control system (DAC) for 100kW, 45.6 MHz has been conceptualized for RF ICRH experimental activities in tokamak. This system will be used for control and monitoring for 2 kW, 20 kW and 100 kW 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 100 kW stage needs four power supplies named plate, filament, screen grid and control grid. For failsafe operation of the system, it needs DAC for control, monitor and synchronization of each RF stage respectively. As per requirement of the DAC, it needs 32 analog inputs, 32 digital inputs, 16 digital outputs and 4 analog outputs with 4 counter channels for synchronization of the system. This paper will describe engineering design of LabVIEW based DAC for 45.6 MHz, 100 kW ICRH system. There are three different threads for application development. (1) Data monitoring in graph/chart form as well as textual values which runs on every 100ms timescale periodically. (2) Control and interlocking for failsafe operation of ICRH system which will be catered by different digital and analog channels. Counter/timer cards will be used for triggering as well as pulse generation as per experiment requirement. (3) Data plotting after shot analysis. The data acquisition hardware should be facilitated with 32 analog inputs, 48 digital input/output and 4 analog outputs. User interface will be designed in LabVIEW with control logic implementation. DAC hardware low device driver should communicate with application logic which will be interfaced with user interface module. National Instruments (NI) data acquisition hardware will provide sufficient channels with required resolution needed for DAC. Keywords— 100 kW RF amplifier, ICRH DAC, LabVIEW, Data monitoring, Control and interlocking, Data plotting
I.INTRODUCTION Ion Cyclotron Resonance Heating System is an integral part of the future fusion reactors. For fusion reactors the power levels required are of the order of tens of Megawatt in the frequency range of 10-100 MHz. The megawatt
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level RF power is dumped into plasma with the help of different antennas through different co-axial transmission lines and hence Megawatt level RF generator becomes the building block of ICRH System for fusion reactors. To achieve MW level RF power different amplifier stages starting from mW, 2-3 Watts, 200 Watts, 2 kW, 20 kW, 200 kW are used. These amplifier stages of 2 kW and above have RF tubes like triodes and tetrodes which need multiple 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, normal switching off and emergency switching off sequence. These amplifier stages above 2 kW level also needs proper cooling and one need to follow certain sequence of operation and have interlock with cooling during operation. DAC can control, monitor and acquire the data as well as interlock signals of high voltage power supplies for operating various RF amplifier stages with the help of real time controller. II. 100 KW ICRH-RF GENERATOR SYSTEM RF Generator of 45.6 MHz, 100kW level has been developed for ICRH experiments on tokamak like ADITYA, SST-1. Fig. 1 shows a complete power chain of 100 kW amplifier which, comprises of (A) Signal generator of which output is amplified through (B) low power amplifier, (C) pre-Driver 2 kW stage, (D) pre driver 20 kW stage, (E) High power 100 kW amplifier stage and different DC power supplies rated 4kV, 1Amp; 7.5 kV, 6Amp & 10KV, 20A which fed to pre-driver stages C, D & E respectively. These power supplies are accommodated in a single panel. It can be operated and controlled through manual mode as well as using PLC. It generates RF power at 45.6 MHz frequency which dumped into tokamak as per experiment requirement. 50ohm coaxial copper (6’’ to 9’’) transmission (Tx) lines are used to carry the generated RF power from generator to load. Using an antenna, generated RF power is dumped into tokamak
2015 IEEE INTERNATIONAL CONFERENCE ON ELECTRICAL, COMPUTER AND COMMUNICATION TECHNOLOGIES
Figure 10: Schematic of 45.6 MHz, 100kW ICRH Generator
Fig. 12.1: Pictorial flow of ICRH DAC
DAC system architecture Fig. 11: Block diagram of ICRH DAC
III. DAC SYSTEM DESIGN
NI multi function data acquisition hardware will be used for ICRH DAC system. Each RF stage needs to control and monitor for failsafe operation. For a complete operation of the RF generator system the data needs to be acquired at a high speed. NI DAQ hardware can acquire data at a high speed (1ms) for the same. It provides 32 analog inputs, 48 digital input/output and 4 analog outputs. Signals for control and monitoring will be fed to NI DAQ hardware directly to its channels. It has 16 bit resolution for analog to digital as well as digital to analog signal conversion. It has maximum analog output update rate 900kS/s, maximum digital I/O rate 1MHz and 500kS/s sampling rate for a single channel. It has USB bus and digital triggering facility which provide an ease of access. It integrates high performance analog, digital and counter/timer functionality. It can be used to achieve high speed data acquisition and control needed for ICRH DAC system.
Fig.2 shows each stage of ICRH DAC system. Each RF amplifier stage is interfaced with field I/O using front end electronics which has interfaced with NI DAQ hardware along with user control computer system. DAC system acquires signals from field I/O which has been interfaced using front end electronics. It will be configured using NI LabVIEW (Laboratory Virtual Instrument Engineering Workbench) which is a system-design platform and development environment for a visual programming language from National Instruments. Front end electronics has been designed and developed in house of IPR. It consist signal conditioning and isolation cards for analog input/output as well as digital input/output. Each card has been assembled, tested and successfully installed in DAC rack with its power supply in house of IPR. These cards are used for isolation and interlocking of signals during operation of the system. An industrial computer system will be used to operate and control the DAC system. Fig. 3.1 and 3.2 shows the pictorial flow of the DAC. It will monitor the system at every 100ms. Acquisition and control will be at ≥ 1 kHz. NI DAQ hardware is capable of perform both tasks. NI MAX (Measurement and Automation Explorer) is used to interface NI DAQ hardware with the user control computer system. It will check its connectivity using self test.
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2015 IEEE INTERNATIONAL CONFERENCE ON ELECTRICAL, COMPUTER AND COMMUNICATION TECHNOLOGIES
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Fig.5.1 Test Setup
Fig. 3.2: Data Acquisition and Control
Fig.4: Sample user interface for 2kW RF generator developed in LabVIEW It
User will send request to NI DAQ hardware to perform different instances for failsafe operation of the system. User interface will be executed using START and STOP button developed in labview. It will check status and get information from calibration file. NI DAQ hardware will accept acquisition request after execution of user interface as shown in figure. 3.2. Acquired data will be displayed in form of graph/ chart and stored on the DAC computer system. It will check status of each stage of the system and acknowledge to the user which will be displayed on LabVIEW based GUI. Development of Sample test bad
User interface and back end programming for ICRH DAC system will be developed in LabVIEW. It is a powerful tool for User Interface (UI) Event programming facilitated by National Instruments. It is facilitated with LabVIEW Technical Resource (LTR) is the leading independent source of LabVIEW-specific information. Each LTR issue presents powerful tips and techniques and includes a
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Figure 5.2: Acquisition of sine wave of 1 kHz, 5V using test set up
Resource CD packed with VIs, Utilities, Source Code, and Documentation. It helps to develop user friendly interface with optimized solutions. Fig. 4 shows sample user interface for 2kW RF generator. It will display channel settings, trigger settings and monitoring display. It has been tested with NI DAQ hardware and working properly without fail. ICRH DAC will have control VI for 2kW; 20kW and 100kW respectively having ON/OFF, READY and TRIP status of each RF amplifier stage. It will have set voltage, calibration file, Logbook, RF Shot panel and RF pulse generation. Different parameters can be set using each control panel of user interface, as per need of experiment. There will be a number of VIs for monitoring and control which will be merged to ICRH DAC VI which is a master VI of the DAC system. It will be run on LabVIEW platform. Its executable (.exe) can be generated which can be installed on another user control pc without labview software. Fig.4: Sample user interface for 2kW RF generator developed in LabVIEW It can handle large amount of data traffic and run without fail.
2015 IEEE INTERNATIONAL CONFERENCE ON ELECTRICAL, COMPUTER AND COMMUNICATION TECHNOLOGIES
test panel digital output can be generated and it can be monitored on oscilloscope. It can be manipulated as per requirement. Digital triggering has been tested using +5V digital output using which trigger based data acquisition can be programmed and implemented. Using this setup all analog and digital channels of NI DAQ hardware has been checked and tested. V. CONCLUSION
Figure 5.3: Digital input/ output using NI DAQ hardware
IV.D ISCUSSION AND V ALIDATION
Fig. 5.1 shows test set up for analog input -output and digital input-output using Wavetek 50 MHz function generator and YOKOGAWA CA11 calibrator (0 to 30 V, 20mA Handy Calibrator). Output of function generator is fed to NI DAQ hardware using single ended BNC cable. Calibrator output can feed to NI DAQ hardware using hardwires. NI DAQ hardware is interfaced with user control computer system through USB bus. A sine wave of 1 kHz, 5V is fed to analog input (AI) channel of NI DAQ which is monitored on NI MAX test panel as shown in Fig. 5.2. Using test panel all channels can be checked, tested and monitored. It can be accessed using NI MAX. Fig.5.3 shows acquisition and control of digital input – output. A square wave of +5V is fed to digital input (DI) channel. LED will glow when digital input (DI) is available. From
Prototype ICRH DAC system will provide real time control and data acquisition using NI DAQ hardware. LabVIEW platform helps to develop an interactive user interface for fail safe operation of the system. It provides high speed data acquisition and control. We have tested NI DAQ hardware with sample user interface developed in LabVIEW. It works properly and gives high performance functionality as well as reliability. REFERENCES [1].
[2].
[3].
[4].
Sunil Kumar, Raj Singh, Kulkarni S.V. and Bora D., Layout of 200 kW RF Generator for Aditya ICRH System, IPR Technical Report, IPR/TR-47/192, December 1992. Sunil Kumar, Raj Singh, Kulkarni, S.V. and Bora, D., Design of 200 kW RF Generator for Aditya ICRH System, IPR Technical Report, IPR/TR- 41/92, February 1992. Ramesh Joshi, H.M. Jadav, Manoj Parihar, B.R. Kadia, K. M. Parmar, A. Varia, K. Mishra, Y.S.S. Srinivas, R. A. Yogi, A. Gayatri, Raj Singh, Sunil Kumar and S.V. Kulkarni, DAC Software System for 91.2 MHz, 1.5 MW ICRH System for SST1, 26th National Symposium on Plasma Science and Technology, (PLASMA 2011), December 20-23, 2011, BIT Mesra, Patna Campus, Paper no. NF-09 http://www.ni.com/pdf/academic/us/journals/An_Instrumentatio n.pdf
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