965   sample value control block attribute should be encoded in the APDU rather than encoded in each ASDU

Created: 28 Dec 2012

Status: In Force (green)

Part: Part 9-2 (2011; Edition 2)

Links:

Page: 23

Clause: 8.5.2 Presentation layer functionality

Paragraph: Table 14

Category: No impact on this part

Issue

The confifuration attribute of sample value control block of the scope of the sample value frame, so they should be outside of the ASDU; but now they are encoded in each ASDU, there are two main disadvantages:
(1) it is not efficient if there are N ASDU in one sample value frame, they are encoded, transmitted, decoded N times, and N-1 times of them are meaningless;
(2) it is confused to understand the usa case of several ASDUs in one sample value frame;
these attributes include: svID, datset, confRev, smpSynch, smpRate, smpMod;

Proposal

svID, datset(Optional), confRev, smpSynch, smpRate(Optional), smpMod(Optional) should be encoded in the SavPdu, before noASDU;
only smpCnt and refrTm(Optional) should be encoded in each ASDU,