
BRONKHORST®
Page12RS232interface 9.17.027
3.3.3 RS232ASCIIprotocol
AnASCIIprotocolisusedontheexistingRS232‐HOST.TobecompatiblewithexistingdriversoftwaretheASCII
protocolisavailable.
AbasicdatalinkmessageiscodedinASCIIasfollows:
length node data
: len1 len2 node1 node2 data1 data2 CR
Byte Explanation
: Initialcharacter(semicolon)
Len1,len2 Lengthofmessageincludingthenodeaddressinbytes,so(len1,len2)is
thebasicmessagelength+1.
node1,node2 nodeaddressofdestination(PCtoHOST)
nodeaddressofsource(HOSTtoPC)
data1,data2 messagefield
CR terminationcharacter
Allbytes(excepttheinitialandterminationcharacter)areconvertedfrom1binarybyteto2hexadecimalbytesin
ASCIIrepresentation.
Example:binarydatabyte0x2A‐‐>hexadecimalASCIIcharacters0x32,0x41.
AspecialmessagetypeisusedtopasserrormessagesfromtheHOSTtothePC.Itsstructure
isasfollows:
0x01 error
: 0x30 0x31 error1 error2 CR
Byte Explanation
: initialcharacter
0x30,0x31 lengthofthemessage(1byte)
error errorcode,twodigitHEXnumber
CR terminationcharacter
Theerrorcodecanhavethefollowingvalues:
Value Meaning
3 proparprotocolerror
4 proparprotocolerror(orCRCerror)
5 destinationnodeaddressrejected
9 responsemessagetimeout
1,2,8 generalerror
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