04-07-2012, 03:40 PM
Continuous and Real-Time Data Acquisition Embedded System for EAST
[attachment=26710]
Abstract
The Experimental Advanced Superconducting
Tokamak (EAST) is planned to run 1000 s plasma discharges in
the near future. In this steady-state operation, the data acquisition
system (DAS) will be required to continuously acquire diagnostic
signals, transfer diagnostic data from the digitizer front-end to
the data servers in order that the data is retrieved by the experimenters
in real-time. Another disadvantage is that current data
acquisition systems consist of many devices which are connected
through various cables to provide the requested functionality.
INTRODUCTION
THE Experimental Advanced Superconducting Tokamak
(EAST) has been designed and developed by the Institute
of Plasma Physics, Chinese Academy of Sciences (ASIPP), it is
planned to eventually create plasma lasting 1,000 consecutive
seconds. Conventional data acquisition systems in EAST, for
instance, the CAMAC digitizers and the New PCI (NPCI) cards
[1] are usually adapted for short-pulse discharge, and their sampling
rates and total acquiring durations are typically limited due
to the restricted capacity of the storage media on board. If they
are to be used for a long-time plasma discharge, a much slower
sampling rate may be adopted, which decreases the accuracy
and omits some detailed physical information of the signals.
HARDWARE STRUCTURE
The new data acquisition system integrates signal conditioning,
a data acquiring, data collecting and processing
function into the single board based embedded system. It has
twelve simultaneously acquiring channels, 250 kS/s per channel
and supplies the standard signal for test of the global system.
Fig. 2 shows the hardware architecture of this data acquisition
system.
SOFTWARE STRUCTURE
The data acquisition software for the embedded system has
been written in the object-oriented programming language.
The software is developed and cross-compiled for the
ARM architecture on a host system using cross-tools 3.4.1.
Fig. 7 shows the structure of the software system. There are
three important technologies introduced into this system. It includes
compression technology; time slice [8] technology and a
web service for configure the embedded system.
CONCLUSION
In this paper a new data acquisition device was developed on
the basis of an embedded system, different from the structure of
a conventional data acquisition system. It integrates signal conditioning,
signal converting and data processing and transmission
in one board. Some new technologies are introduced into
this system such as ARM, FPGA, LZO technologies, and time
slice mechanism and embedded web server. To a certain degree,
this system avoids the disadvantages about long cables, and enhances
the integration level.
[attachment=26710]
Abstract
The Experimental Advanced Superconducting
Tokamak (EAST) is planned to run 1000 s plasma discharges in
the near future. In this steady-state operation, the data acquisition
system (DAS) will be required to continuously acquire diagnostic
signals, transfer diagnostic data from the digitizer front-end to
the data servers in order that the data is retrieved by the experimenters
in real-time. Another disadvantage is that current data
acquisition systems consist of many devices which are connected
through various cables to provide the requested functionality.
INTRODUCTION
THE Experimental Advanced Superconducting Tokamak
(EAST) has been designed and developed by the Institute
of Plasma Physics, Chinese Academy of Sciences (ASIPP), it is
planned to eventually create plasma lasting 1,000 consecutive
seconds. Conventional data acquisition systems in EAST, for
instance, the CAMAC digitizers and the New PCI (NPCI) cards
[1] are usually adapted for short-pulse discharge, and their sampling
rates and total acquiring durations are typically limited due
to the restricted capacity of the storage media on board. If they
are to be used for a long-time plasma discharge, a much slower
sampling rate may be adopted, which decreases the accuracy
and omits some detailed physical information of the signals.
HARDWARE STRUCTURE
The new data acquisition system integrates signal conditioning,
a data acquiring, data collecting and processing
function into the single board based embedded system. It has
twelve simultaneously acquiring channels, 250 kS/s per channel
and supplies the standard signal for test of the global system.
Fig. 2 shows the hardware architecture of this data acquisition
system.
SOFTWARE STRUCTURE
The data acquisition software for the embedded system has
been written in the object-oriented programming language.
The software is developed and cross-compiled for the
ARM architecture on a host system using cross-tools 3.4.1.
Fig. 7 shows the structure of the software system. There are
three important technologies introduced into this system. It includes
compression technology; time slice [8] technology and a
web service for configure the embedded system.
CONCLUSION
In this paper a new data acquisition device was developed on
the basis of an embedded system, different from the structure of
a conventional data acquisition system. It integrates signal conditioning,
signal converting and data processing and transmission
in one board. Some new technologies are introduced into
this system such as ARM, FPGA, LZO technologies, and time
slice mechanism and embedded web server. To a certain degree,
this system avoids the disadvantages about long cables, and enhances
the integration level.