= OpenIEC61850 User Guide
include::common-settings.txt[]

:numbered:

== Intro

OpenIEC61850 is a library implementing the IEC 61850 standard based on
the MMS mapping for client and server communication. It is licensed
under the Apache 2.0 license. OpenIEC61850 includes a console client
and server as well as a gui client.
    
=== Distribution

After extracting the distribution tar file the OpenIEC61850 library
can be found in the build/libs-all folder. For license information
check the _license_ directory in the distribution.

==== Dependencies

Besides the OpenIEC61850 library the folder _build/libs-all/_ contains the
following external libraries:

* *jasn1* - a library from the jASN1 project doing BER
   encoding/decoding, Copyright 2011-17 Fraunhofer ISE, Author: Stefan
   Feuerhahn, License: LGPLv2.1 or later, http://www.openmuc.org

* *slf4j-api* - a popular logging API. It is only needed if
   openiec61850 is used to implement a server. The client part does
   not log anything.  License: MIT, http://www.slf4j.org

* *logback-core/logback-classic* - an actual logger implementation of
   the slf4-api. It is used by the console server application to
   output log information. It can be replaced by a logger of your
   choice that supports the slf4j API. Like slf4j it is only needed
   for server implementations. License: EPLv1.0 and LGPLv2.1,
   http://logback.qos.ch

* *jcalendar* - a calendar library needed by the client GUI. You don't
   need this dependency if you don't use the client gui.  (C)
   1999-2011 Kai Toedter, License: LGPLv3,
   http://toedter.com/jcalendar/

    
=== Console & GUI Applications

You can execute the console client and server through the scripts
found in the folder _run-scripts_.  Executing the scripts without any
parameters will print help information to the screen. Note that under
Unix/Linux you need root privilages if you want the server to listen
on any port lower than 1000.

Instead of running the applications from the terminal you can create
Eclipse project files as explained in our
link:https://www.openmuc.org/faq/gradle_getting_started/[FAQs] and run
them from within Eclipse.

    
=== OSI Stack

The OpenIEC61850 library includes an OSI stack implementation as it is
needed by the IEC 61850 MMS mapping. The API of the OSI stack and the
OSI transport layers are made public so that they can be used by other
projects.

* *josistack* - implements the Application Control Service Element
   (ACSE) protocol as defined by ISO 8650 or ITU X.217/X.227, the
   lower ISO Presentation Layer as defined by ISO 8823/ITU X226, and
   the ISO Session Layer as defined by 8327/ITU X.225.

* *jositransport* - implements RFC 1006 and the OSI Transport Service
   Layer.


== Using OpenIEC61850

The easiest way to learn how OpenIEC61850 works is by running and
analyzing the console client and server applications. You might want
to look at the source code of the console applications to get an
understanding of how they work. They can be used as a basis for you to
code your individual client or server applications.

An IEC 61850 device that is to be controlled or monitored is called an
IEC 61850 server. An IEC 61850 server normally listens on port 102 for
incoming connection requests by IEC 61850 clients.
        
=== Client

If you want to connect to an IEC 61850 server, you should first create
an instance of ClientSap (SAP = Service Access Point) and configure it
to your needs. Then you build up the association to the server using
the associate() method.
    
=== Server

First get a List of ServerSaps using the method
ServerSap.getSapsFromSclFile(). This method reads in the SAP from the
given ICD file. Take the ServerSap you want to run and configure it to
your needs (e.g. set the port to listen on). The ServerSap includes
the complete device model defined in the ICD file. Retrieve a copy of
it using the method getModelCopy(). Tell the ServerSap to start
to listen on the configured port using startListening(). This is a
non-blocking function.

=== Data Model

An IEC 61850 server contains a treelike data model that contains at
its leafs the data (integers, boolean, strings etc) that can be
accessed by clients. Clients can also retrieve the whole data model
from the server.

The upper most model node ist called "server". In OpenIEC61850 it is
an object of type ServerModel. The server node contains 1..n logical
devices (LD). A logical device may contain 1..n logical nodes (LN). A
logical node may contain 1..n data objects. In OpenIEC61850 the
logical nodes do not contain complete data objects but instead contain
so called functionally constraint data objects (FCDO). An FCDO is a
data object that is split up by functional constraint. An FCDO can
contain a combination of other FCDOs, arrays, constructed data
attributes and/or basic data attributes.

All nodes of the server model in OpenIEC61850 are of one of the
following seven types: 

* ServerModel
* LogicalDevice
* LogicalNode
* FcDataObject
* Array
* ConstructedDataAttribute
* BasicDataAttribute

They all implement the ModelNode interface. The nodes FcDataObject,
Array, ConstructedDataAttribute and BasicDataAttribute also implement
the interface called FcModelNode because they are considered
functionally constraint data in the standard. Many of the services of
IEC 61850 can only be applied to functionally constraint data
(e.g. GetDataValues and SetDataValues).

When programming a client you get a copy of the server model either
through ClientAssociation.retrieveModel() or
ClientAssociation.getModelFromSclFile(). When programming a server you
get a copy of the server model through the ServerSap.getModelCopy()
function.

You can then navigate through the model using several functions:

* ServerModel.findModelNode(ObjectReference objectReference, Fc fc)
  will search for the subnode with the given reference and functional
  constraint.

* ModelNode.getChild(String name, Fc fc) will return the child node
  with the given name and functional constraint.

* ModelNode.getBasicDataAttributes() will return a list of all leaf
  nodes (basic data attributes) of the model node.

    
    
== Modifying and Compiling OpenIEC61850

We use the Gradle build automation tool. The distribution contains a
fully functional gradle build file (_build.gradle_). Thus if you
changed code and want to rebuild a library you can do it easily with
Gradle. Also if you want to import our software into Eclipse you can
easily create Eclipse project files using Gradle. Just follow the
instructions on our
link:https://www.openmuc.org/faq/gradle_getting_started/[FAQ site].

== IEC 61850 Concepts    
    
=== Data Sets

Data sets (DS) form a group/set of data. Data sets can be used to read
or write several data objects/data attributes at once using a single
request/response message exchange. The service used for this are
GetDataSetValues and SetDataSetValues. Besides the data set
services the reporting, logging, GOOSE and sampled value services also
use the data set concept.

The data attributes or data objects that are part of a data set are
called the members of a data set. Only functionally constraint data
may be a member of a data set.

The IEC 61850 standard defines five ASCI services related to data sets:

* *GetDataSetValues* to get the value of all members of the data set.

* *SetDataSetValues* to set the value of all members of the data set.

* *CreateDataSet* to create a new data set dynamically.

* *DeleteDataSet* to delete a data set that was created.

* *GetDataSetDirectory* to get the list of all existing data sets in
   the server

Two types of data sets exist:

* *Persistent data sets* - they have a reference of the format
   LDName/LNName.DataSetName . They are visible to all
   clients. Persistent data sets can be preconfigured in the SCL
   file. In this case they cannot be deleted. Persistent data sets can
   also be dynamicall created by clients. In this case they may be
   deleted again later. Dynamically created data sets will be
   automatically deleted once the server stops.

* *Non-persistent data sets* - they have a reference of the format
   @datasetname . They are only visible to the client that created it
   through the CreateDataSet service. These data sets only exist as
   long as the association is open.


=== Reporting

Reporting allows a server to send data based on events and without
explict request by the client. What data is sent and the events that
cause reports are configured through so called report control blocks
(RCB).

The standard distinguishes between two types of reporting: buffered
reporting and unbuffered reporting. With buffered reporting reports
are buffered by the server in case a connection to the client is
interrupted. This way reports can be sent after the client has
connected again. Buffered reporting is configured through buffered
report control blocks (BRCB). Unbuffered reporting is configured
through unbuffered report control blocks (URCB).

RCBs are located within logical nodes of the server's data model
(i.e. the server's ICD/SCL file). They are fixed and cannot be deleted
or added at runtime. An RCB is blocked once a client has registered to
receive reports (by enabling it). That means a single RCB cannot send
reports to several clients in parallel.

RCBs are always associated with a specific <<_data_sets,data set>>
that must be located in the same logical node as the RCB. A subset of
the data set's members will be reported if any of the configured
events occures. The associated data set of the RCB can be
dynamically changed by a client at run-time.

RCBs are located in logical nodes in the server's model tree. Therefor
the reference of an RCB is of the form
LogicalDeviceName/LogicalNodeName.RCBName . Even though RCBs can only
reference data sets located in the same logical node as the RCB
itself, they can still monitor data from other logical nodes because
the data set's members can be located in other logical nodes.

The following events can cause a server to send a report:

. The client issues a general interrogation. 

. A data attribute that is part of the associated data set changes or
is updated.

. Periodic sending of reports has been enabled by setting the
integrity period of an RCB.

Whether one of these events really causes a report to be sent is
configured through the RCB.

A report control block contains the following fields:

* Configuration fields. They can only be written if the RCB has not
  been enabled nor reserved by another client:

** *RptID* - The report ID identifies the RCB. If not set, it equals
   the RCB reference. The RptID will be sent with every report so that
   the client can identify the RCB responsible for the report.

** *DatSet* - The reference of the data set associated with this
   RCB. It must be located in the same logical node as the
   RCB. Members of this data set will be reported whenever the
   configured events occure. The data set reference as it is set in an
   RCB must contain a dollar sign instead of a dot to separate the
   logical node from the data set name, e.g.:
   'LDevice1/LNode$DataSetName'

** *OptFlds* - A bitstring where each bit indicates whether an
   optional field is included in the reports caused by this RCB. The
   following optional fields exist: sequence-number, report-
   timestamp, reason-for-inclusion, data-set-name, data-reference,
   buffer-overflow, entryID, segmentation, and conf-revision. For
   URCBs the values of buffer-overflow and entryID are ignored.

** *BufTm* - In case of an event that causes a report the server will
    wait for _BufTm_ ms for other events. All data that is to be
    reported because of events in this time span is sent in a single
    report.

** *TrgOps* - Specifies which events will trigger reports. Possible
    events are:

*** data change (dchg)

*** quality change (qchg)

*** data update (dupd)

*** integrity - if enabled the server will send periodic integrity
    reports to the client. Integrity reports will contain the current
    values of all members of the referenced data set.

*** general interrogation (GI).

** *IntgPd* - The integrity period specifies an interval in ms for the
    periodic sending of intergrity reports. 

** *PurgeBuf* (only part of BRCBs not URCBs) - 

** *EntryID* (only part of BRCBs not URCBs) - 

* Information fields: can only be read:

** *SqNum* - the current sequence number of the RCB. After sending a
   report the RCB will increment the sequence number by one.

** *ConfRev* - The configuration revision is a counter representing the number of
   times the referenced data set was changed.

** *Owner* - Shall be equal to the IP of the client that reserved the
    RCB. Shall be NULL (i.e. the empty string) if the RCB is not
    reserved.

** *TimeOfEntry* (only part of BRCBs not URCBs) 

* Functional fields: The following fields of the RCB can be read or
written to execute functions:

** *Resv* (only part of URCBs not BRCBs) - Before doing anything with
    an RCB a client should reserve it by setting this field to
    true. If the setting was successful the RCB will be reserved
    exclusively for this client. Enabling an RCB that has not been
    reserved implicitly reserves it.

** *ResvTms* (only part of BRCBs not URCBs) - This attribute of BRCBs
    is optional. If not present the control block is reserved by
    simply enabling it. A ResvTms value of -1 indicates that the
    control block was reserved by configuration for a certain set of
    clients. A value of 0 indicates that the BRCB is not reserved. A
    client can reserve the control block by writing a value largen
    than 0. The value represents the number of seconds that the
    reservation shall be maintained after the association was closed
    or interrupted.

** *RptEna* - By setting this variable to true reporting will be
    enabled. Note that changing/writing and configuration fields of
    the RCB will fail as long as reporting is enabled.

** *GI* - General Interrogation. Setting this parameter to true will
    initiate a report to be sent to the client. This report will
    contain all the data of the associated data set. The GI parameter
    will be reset to false automatically by the server once the report
    has been sent.


A report always contains the following information fields:

* *RptID* - The report ID identifies the RCB that has caused the
   generation of the report. It equals the RptID field of the RCB.

* *OptFlds* - It is equal to the OptFlds field of the corresponding
   RCB.

* *SqNum* (optional, included if OptFlds.SequenceNumber is true) - The
   sequence number of the report. It is equal to the SqNum field of
   the corresponding RCB by the time it was sent.

* *TimeOfEntry* (optional, included if OptFlds.report-timestamp is
   true) - specifies the time when the Entry ID was created.

* *DatSet* (optional, included if OptFlds.dataset-name is true) - The
   reference of the data set whose data is sent in this report.

* *BufOvfl* (optional, only included if it is a buffered report and
   OptFlds.buffer-overflow is true) - Indicates the server lost report
   entries due to a buffer overflow. Only applies to buffered
   reporting.

* *EntryID* (optional, only included if it is a buffered report and
   OptFlds.entryID is true) - Entry identification ToDo

* *ConfRev* (optional, only included if OptFlds.conf-rev is true) - It
   is equal to the ConfRev field of the corresponding RCB.

* *SubSqNum* (optional, included if OptFlds.segmentation is true) - In
   case that a long report does not fit into one message, a single
   report shall be divided into subreports.  Each subreport shall have
   the same sequence number and a unique SubSqNum.

* *MoreSegmentsFollow* (optional, included if OptFlds.segmentation is
   true) - indicates that more subreports with the same SqNum follow.

* *Inclusion Bitstring* - A bit string whose length equals the number
   of data members of the referenced data set. Each bit indicates
   whether the corresponding data member is included in the report or
   not.

* *Data-references* (optional, included if OptFlds.data-reference is
   true) - The references of the reported data set members.

* *Values* - The values of the reported data set members.

* *Reason Codes* (optional, included if OptFlds.reason-for-inclusion
   is true) - The reason codes indicate for each reported value, the
   reason why it was reported. Possible reasons are data change,
   quality change, data update, integrity, general interrogation,
   and application trigger. Several reasons can be true for a single
   reported value.

A client that wants to receive reports from a certain RCB would
usually first attempt to reserve the RCB. If successful he would then
configure the RCB as he wishes. Finally he would enable reporting.


== Terminology

* *BRCB* - Buffered Report Control Block 

* *DS* - Data Set

* *LD* - Logical Device

* *LN* - Logical Node

* *SAP* - Service Access Point

* *URCB* - Unbuffered Report Control Block

== Authors

Developers:

* Stefan Feuerhahn

Former developers:

* Claus Brunzema
* Bertram Lückehe
* Chau Do
* Tobias Weidelt
* Michael Zillgith
