IEC 61334-6:2000 pdf free download

IEC 61334-6:2000 pdf free download Distribution automation using distribution line carrier systems – Part 6: A-XDR encoding rule
1 Scope and object
This part of lEC 61334 defines a set of encoding rules – the A-XDR3) encoding rules – thatmay be used to derive the specification of a transfer syntax for values of types defined in theDLMS core standard using the ASN.1 notation (see lEC 61334-4-41).These A-XDR encodingrules are also to be applied for decoding such a transfer syntax in order to identify the datavalues being transferred.
The A-XDR encoding rules
. are used at the time of communication;.provide optimal4) encoding for DLMS PDUs.
NOTE Provided that A-XDR ensures optimal encoding for DLMS PDUs, it is intended to be the default encodingrule for DLMS-based communication protocols.Nevertheless, the default – and also the possibly usable optional -encoding rules will be specified in the Application Layer document of the given protocol (for example,IEC61334-4-42),as part of the Application context.
Normative references
The following normative documents contain provisions which，through reference in this text,constitute provisions of this part of lEC 61334.For dated references, subsequent amendmentsto，or revisions of，any of these publications do not apply. However， parties to agreementsbased on this part of iEc 61334 are encouraged to investigate the possibility of applying themost recent editions of the normative documents indicated below.For undated references, thelatest edition of the normative document referred to applies.Members of lS0 and lEC maintainregisters of currently valid lnternational Standards.
IEC 61334-4-41:1996,Distribution automation using distribution line carrier systems – Part 4:Data communication protocols – Section 41: Application protocols – Distribution line messagespecification
IEC 61334-4-42:1996,Distribution automation using distribution line carrier systems – Part 4:Data communication protocols – Section 42:Application protocols – Application layer
ISO/IEC 8825-2:1997,Information technology -ASN.1 Encoding rules: Specification of packedencoding rules (PER)
ITU-T Recommendation X.208:1988,Specification of Abstract Syntax Notation One (ASN.1)
3 General characteristics of A-XDR A-XDR specifies encoding rules which can be used to encode and decode the values of an abstract syntax defined as the values of a single ASN.1 type (the outermost type). This single ASN.1 type is either a simple type or a composite type. A component of a composite type may be a simple type or a composite type itself.
The A-XDR encoding rules exploit the fact that the sender and the receiver of a DLMS PDU are operating exactly the same specification of the abstract syntax. While with BER the encoding of every value of any type of abstract syntax is constructed in type-length-value (TLV) style, A-XDR encodes the type and the length of the value only when this information is necessary. This implies that without knowledge of the type of value encoded it is not possible to determine the structure of the encoding.