Configuring the Bridge
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3.5HowMapping Works:TCP/IPtoModbusPlus
EachModbusPlusmessage destination isdefined byafive--byteModbusPlus
routing path.The use of the pathis specificto eachtype ofModbusPlusdevice.
Refertothe guidebooks supplied withyourModbusPlusdevicesfordetails,or
refertothe ModbusPlusNetworkPlanning and Installation Guide,partnumber
890 USE 100 00, fora generaldescription ofModbusPlusrouting paths.
Messagesreceived bythe bridge fromEthernethostnodes contain an embedded
DestinationIndexbyteinthe range 1... 255 decimal.Thisbytecorrespondstothe
dest_idx fieldinmessages constructed byModicon panelsoftwaresuch as
Modsoft and Concept.
The bridge usesthe Destination Indexbyteto determine the type ofrouting to be
made.
3.5.1Destination Indexes 1 ... 249: MappedRouting
The bridge usesDestination Indexes1... 249 tomap messagesfromaTCP/IP
node toaModbusPlusdestination node.
The bridge mapsDestination Indexesinthisrange to one of249 possibleModbus
Plusrouting paths.EachDestination Index value mapstoalocation inaModbus
Plusmapping table,whichcontainsafive--byteModbusPlusroutingpathtothe
destination node.
Yourconfigurationof the bridge mustinclude entriesintothe bridge’smapping
tabletocorrelatethe Destination Indexestoyour routing pathsforModbusPlus
nodesinyourapplication.
Section 3.6 describeshowtosetup the TCP/IPtoModbusPlusmapping table.