IEC_60870-5-104_Amed._1_Ed.1.pdf

57/658/CDCOMMITTEE DRAFT(CD)IEC/TC or SC:TC 57Project numberIEC 60870-5-104 Amed.1 Ed.1Title of TC/SC:Power system control and associatedcommunicationsDate of circulation2003-08-15Closing date for comments2003-11-21Also of interest to the following committees Supersedes document57/647/MCRFunctions concerned:Safety EMC Environment Quality assuranceSecretary:THIS DOCUMENT IS STILL UNDER STUDY AND SUBJECT TOCHANGE.IT SHOULD NOT BE USED FOR REFERENCE PURPOSES.RECIPIENTS OF THIS DOCUMENT ARE INVITED TO SUBMIT,WITHTHEIR COMMENTS,NOTIFICATION OF ANY RELEVANT PATENTRIGHTS OF WHICH THEY ARE AWARE AND TO PROVIDESUPPORTING DOCUMENTATION.Title:Amendment 1 to IEC 60870-5-104 Ed.1:Telecontrol equipment and systems-Part 5-104:Transmission protocols-Functional enhancements to IEC 60870-5-104Introductory noteFORM CD(IEC)2002-08-08Copyright 2003 International Electrotechnical Commission,IEC.All rights reserved.It ispermitted to download this electronic file,to make a copy and to print out the content for the solepurpose of preparing National Committee positions.You may not copy or mirror the file orprinted version of the document,or any part of it,for any other purpose without permission inwriting from IEC.57/658/CD 2INTERNATIONAL ELECTROTECHNICAL COMMISSIONTECHNICAL COMMITTEE NO.57 POWER SYSTEMS CONTROL AND ASSOCIATED COMMUNICATION A Companion standard oftelecontrol protocol series IEC 60870-5 Draft:Telecontrol equipment and systems Part 5:Transmission protocols Section 104 A1 :Functional enhancements to IEC 60870-5-104Revision 1.0This draft has been prepared by working group WG0357/658/CD 3INTRODUCTIONThis amendment to the IEC 60870-5-104 has been prepared by Working Group 03 Transmission protocols ofthe International Committee TC57 Telecontrol equipment and systems.It contains some clarifications andenhancements to the standard and adds a new clause defining the use of redundant connections.NORMATIVE REFERENCES1IEC 60870-5-104:2000,Telecontrol equipment and systems-Part 5:Transmission protocols Section 104:Network access for IEC 60870-5-101 using standard transportprofiles.57/658/CD 45 DEFINITION OF APPLICATION PROTOCOLINFORMATION APCI5.1 Protection against loss and duplication of messagesFigure 10:Modify Figure 10(shown below)to show t2 starting from the time of receiving the first unconfirmed frame.Thust2 becomes the timeout of the oldest unconfirmed frame;not the most recently received unconfirmed frame:Figure 10 Undisturbed sequences of numbered I format APDUs acknowledged by an S format APDUFigure 11:The receiving station should send an S-frame to confirm the data frames that it has received prior to performingan active close.This permits the sending station to identify which frames have been received prior to theconnection being closed.These frames may be deleted from the sending station.When the connection isreopened,the frame numbers are reset.Modify Figure 11 as shown below and add the corresponding note:Figure 11 Disturbed sequence of numbered I format APDUsStation AStation BI(0,0)I(1,0)I(2,0)Internal counters V afterAPDU was sent or receivedV(S)V(R)01230S(3)Internal counters V afterAPDU was sent or receivedV(S)V(R)01230Ack03Ack0timeoutt2Station AStation BInternal counters V afterAPDU was sent or receivedV(S)V(R)001S(1)sequenceerroractive closeInternal counters V afterAPDU was sent or receivedV(S)V(R)0013Ack0Ack0Active openfollows,see figures17 to 2021I(2,0)I(0,0)Note:To avoid retrans-mission of APDUs thathave already beenaccepted,an S-framemay be sent prior to theactive close.57/658/CD 5Figure 12:The separate timer t1 in figure 12 should be associated with the transmission of each individual APDU.If aconfirmation of an APDU is received before the timeout expires,that timeout is cancelled.The expiring timeoutt1 shown in the original figure 12 applies for APDU 2,which is not confirmed.The timer t1 associated withAPDU 1 is cancelled when S(1)is received.Modify figure 12 to show a timer for each APDU transmitted,and that the timer for APDU 1 is cancelled before itexpires.Figure 12 Time out in case of a not acknowledged last I format APDUStation AStation BInternal counters V afterAPDU was sent or receivedV(S)V(R)00active closeInternal counters V afterAPDU was sent or receivedV(S)V(R)00Ack0Ack0Active openfollows,see figures17 to 20I(0,0)timeoutt1121S(1)1timeoutcancelledX57/658/CD 65.3 Transmission control using Start/StopAmend this clause with the following text and the figures:A state transition diagram for the Start/Stop procedure when a single connection is used between two stations isshown in Figure 17 below.TCPconnectionestablished_startU-frame /or I-frame /CON(Error)or S-frame /CON(Error)U-frame /or I-frame /CON(Error)or S-frame /CON(Error)Controlling Station receives:Controlled Station receives:NOTE:The Controlling Station takes theinitiative for establishing a TCP connectionPendingSTARTEDconnection_U-frame /or I-frame /CON(Error)or S-frame /CON(Error)STARTDT_ACT /STARTEDconnection_U-frame /or I-frame/or S-fra