Bronkhorst RS232 interface Manuel d'utilisateur télécharger pdf (Page 13)

BRONKHORST®

Page13RS232interface    9.17.027

3.3.4 Enhancedbinaryprotocol

Theenhancedprotocolisbinarycoded.Controlsequencesareusedtorecognisethebeginningandendofamessage

inabytestream.AcontrolsequencestartswithaDLEbyte(0x10)andisfollowedbyacontrolbyte.Thefollowing

controlsequencesaredefined:



Firstbyte Secondbyte Function

DLE(0x10) STX(0x02) Startofmessage

DLE(0x10) ETX(0x03) Endofmessage

DLE(0x10) DLE(0x10) Databyte0x10

DLE(0x10) anyother

character

Notallowed.Messagesthatcontainsuchasequencewillbe

ignored.ThereceiverwaitsuntilanewDLESTXsequence.



The[DLEDLE]sequenceisusedtopreventpossibleDLEbytesinthetransmittedbinarydatastreamfrombeing

recognisedasthestartofacontrolsequence.ThesenderreplacesanyDLEbytesinthedatabytwoDLEbytes.The

datalinkofthereceiverwillconverta[DLEDLE]sequencestooneDLEbyte.



IfaRS232error(receiveroverrun,framingerror,notallowedcontrolsequence)occurs,thedatalink

frameisignored.



TheenhancedbinarycodedmessagesbetweenPCandHOSTarestructuredasfollows:



DLE STX seq node len data DLE ETX



Byte Explanation

DLE,STX startsequence

seq messagesequencenumber

node nodeaddressofdestination(PCtoHOST)

nodeaddressofsource(HOSTtoPC)

len lengthofdatafieldinbytes

data messagefield

DLE,ETX endsequence



Theenhancedprotocolallows the transmissionofmore thanone requestat a time.Thesequence numbermakes it

possible to associate the answer to the according request. The HO ST has more than one message buffer where

messagesmaybestored(typical5).Whenthemessagebuffersarefull,theHOSTrespondswithanerrormessage.



TheresponsesfromtheHOSTtothePChavethesamemessageformatastherequest.Anerrormessagehasaspecial

format:

DLE STX seq node 0x00 error DLE ETX



Byte Explanation

DLE,STX startsequence

seq messagesequencenumber,asinrequest

node nodeaddressofsource,asinrequest

error errorcode

DLE,ETX endsequence



Theerrorcodecanhavethefollowingvalues:



Value Meaning

3 proparprotocolerror

4 proparprotocolerror(orCRCerror)

5 destinationnodeaddressrejected

9 responsemessagetimeout

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 41 42

Commentaires sur ces manuels

Pas de commentaire

Bronkhorst RS232 interface Manuel d'utilisateur Page 13

Commentaires sur ces manuels

Produits connexes et manuels pour Logiciel Bronkhorst RS232 interface