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Appendix B.3. Resolving Network Addresses above 255
TheStandardformatforaddressingasimplexpoint iscps(CardPointSubpoint).Eachof thesecomponentsintheaddresssupportsamaximum valueof255.However,whenusing an NDU (Network Display Unit), addresses may be sup plied in a CardAddress format wheretheaddressvaluecouldbesubstantiallylarg erthan255.Intheseapplicationsitwill benecessarytoconverttheCardAddressformatint ocpsformatbeforeconfiguringthe pointsintheFieldServer.
Theformulausedtoconvertbetweenthetwoformats isasfollows:
Cardisthesameforbothformats.
NetworkAddress=((Point1)*256)+SubPoint+1
Thisconversionprocedureisbestillustratedbyme ansofanexample:
Example:
Fromthiswededucethecardnumbertobe5.Thene xtstepistobreaktheaddressinto multiples of 256 in order to determine point and su bpoint. Since this is also a hex denominatedcalculation,aneasywaytodothisis toconvertthevaluetoHex:
2936=0xB78
Now,breakoutthelasttwohexnumbersforsubpoi ntportion,andusetherestforpoint address.Soweget:
0xB=11=(Point1)
0x78=120=SubPoint+1
Solvingthisequation,weget:
Point=12
SubPoint=119
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