1/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010 INTEGRATION OF EPICS AND MDSplus G. Manduchi, A. Luchetta, C. Taliercio, R. Capobianco Consorzio RFX – Euratom-ENEA Association Outline  Introduction  MDSplus Overview  EPICS and MDSplus Integration  MDSplus Channel Archiver  MDSplus Channel Access Server  mdsput Record  mdsaction Record  mdsevent Record  Conclusions

2/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010 MDSplus (1 of 2)  MDSplus is a data system widely used in the fusion community  Provides tools and libraries for the management of a rich variety of data.  Used in several fusion experiments for data acquisition  Used in fusion as a common format to exhcange experimental data

3/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  Data Management  It is the basic layer: handles a wide variety of data types in a uniform way  Every data item is an Expression. Expression may be as simple as scalars, or complex combination of data items  It follows a “python-like” data approach  Database support  Both configuration and experimental results stored in pulse files.  Pulse files are hierarchically organized  Seamless data access for both local and remote pulse files  Distributed pulse files are supported  Support for data acquisition  Actions and devices are concepts which allow integrating new hardware in the systems and supervising the data acquisition process. MDSPlus Main Components (2 of 2)

4/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  MDSplus and EPICS have a limited overlap  EPICS addresses control and supervision  MDSplus addresses Data Acquisition and Data Management  When properly integrated EPICS and MDSplus may offer a pervasive system for the full management of fusion devices  Required integration for:  Data Flow EPICS uses data for control and supervision MDSplus is the data manager and handles both configuration and experimental results Not all data are of interest to EPICS (actually a small fraction)  Co-ordination MDSplus and EPICS Integration (1 of 2)

5/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010 MDSplus-EPICS Integration Overview (2 of 2) PV mdsaction INIT STORE mdsevent(UDP) Channel Archiver (CAC) Ch. Access mdsip (TCP) ADC MDSplus CAS MDSplus Pulse File mdsput EPICS IOC wave

6/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  Mainly intended to store trend data into MDSplus pulse files  Trend data, e.g. from PLC, are traditionally managed in IOC for monitoring and alarm handling  Traditionally, the EPICS Channel Archiver has been used to store trend data in indexed files No more supported, new archiver at SNS uses a Relational Database for storage  A new implementation of Channel Archiver provides storage of trend data in MDSplus pulse files  Written in Java, using the pure java JCA Channel Access Client library and the Java interface of MDSplus  Instead of XML configuration files, it relies on the hierarchical structure of the pulse file  Conversion tools for XML are available (from the old Archiver XML to the MDSPlus XML pulse file description) MDSplus Channel Archiver (1 of 3)

7/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  The MDSPlus Channel Archiver can sustain a much larger data throughput  Tests carried out at RFX pointed out the limits in the old archiver (lost samples and CPU load)  With the new Archiver, data loss (0.05% of the total samples) starts at a rate of 300 kUpdate/s.  In the original EPICS Archiver data loss begins at a rate of 20 kUpdates/s  More Archivers can access the same MDSplus pulse files and data can be read in parallel MDSplus is a rugged data system since it has been used for almost 20 years in fusion devices for handling online and offline data acquisition MDSPlus channel archiver (2 of 3)

8/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  Remote data access was provided by the original EPICS Channel Archiver  Based on XML RPC  Limited support for programmatic data access (management of XML RPC protocol)  When stored on MDSplus pulse files, data are natively available worldwide  Use the mdsip protocol, optimized for communication speed  Available in a variety of languages (Fortran, C, C++, Java, Python, IDL, Matlab)  jScope provides interactive visualization of stored waveforms. MDSPlus Channel Archiver (3 of 3)

9/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  MDSplus pulse files are normally used to contain both configuration and experimental results  Parameters are read from pulse files  Acquired data are written in the same database  In order to let IOC access configuration parameters, a Channel Access server will export the contents of the pulse file MDSPlus Channel Access Server

10/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  mdsput record provides storage of incoming data into MDSplus pulse files  It represents an alternative data path in respect to Channel Access  Channel Access exports PV values  Mdsput stores data either locally or remotely using the mdsip protocol  Local data access may be required for large data throughput, such as camera acquisition MDSplus supports distributed pulse files  It allows storing a single sample or multiple samples when processed  Samples are stored one by one when coming from slow devices  ADC operating at higher sampling speed will interrupt the system when their FIFO is half full, and in this case a set of samples is read in a single operation mdsput Record (1 of 2)

11/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  The time associated with single samples can be either the EPICS time or the relative time from the start of the experiment  For block of samples, time has to be derived in a different way  Two record fields, TRIG and PRD are used for the trigger time and the period, respectively. Based on this information it is possible to associate a timestamp to each sample in the pulse file  Every sample can be a scalar value, an 1D array or a 2D array  Scalar values may be used for storing a single data channel  1D arrays may be used for multichannel ADCs  2D arrays may be used to store data coming from frame grabbers mdsput Record (2 of 2)

12/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  MDSplus defines an “Action” data type which describes an operation to be performed during the experiment sequence.  Often actions refer to device methods.  In MDSplus a device is represented by a set of data items, actually stored in a sub-tree, containing all the required information to specify an hardware device;  Methods are associated with devices: typically an INIT and STORE method  Device Methods can be implemented in C or python and extend MDSplus functionality to support specific hardware  A large set of supported devices is available in the MDSplus Web Site mdsaction record (1 of 2)

13/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  The mdsaction record triggers the execution of an MDSplus action  mdsaction record resembles the SUB record  Basically both execute a routine (e.g. a device method for MDSplus)  However mdsaction record allows to define remote actions, i.e. actions which have to be executed on different machines  This would allow a given IOC to supervise operations on different (possibly embedded) non-EPICS computers mdsaction record (2 of 2)

14/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  MDSplus events are used for asynchronous communication  The latest MDSplus event implementation uses UDP multicast and can be used in real-time  The mdsevent record represents the bridge between MDSplus events and EPICS IOCs  As MDSplus events can also bring data, mdsevent record will also optionally produce data  They are actually implemented as a new Device for the Waveform record  This record represents therefore a possible source of external data for the EPICS IOC mdsevent Record

15/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010  The proposed set of tools and Records aims at providing a closer integration of EPICS and MDSplus  Some work has already been done at NSTX and KSTAR, but none pushed integration so far  Possible future developments could address the integration of the Java Tools of MDSplus in CSS  The final target is a pervasive system covering all the requirements for a large fusion device. Conclusions

16/15 G. Manduchi EPICS Collaboration Meeting, Aix-en-Provence, Spring 2010 INTEGRATION OF EPICS AND MDSplus G. Manduchi, A. Luchetta, C. Taliercio, R. Capobianco Consorzio RFX – Euratom-ENEA Association QUESTIONS?