Configuring the Bridge
34
3.6Setting theMapping:TCP/IPtoModbusPlus
As you design yourapplication you should defineaDestination Index value
(1... 249)foreachModbusPlusnode towhichyourEthernethostwill originate
messages.Edit the bridge’smappingtabletocorrelate eachDestination Index
value tothe five--byteroutingpathforthe intended ModbusPlusnode.
3.6.1MB+Mapping TableLayoutandDefaultEntries
The MB+Mapping tablecontains249 fields,labeled MBP_1 through MBP_249.
Thesefieldsdefine ModbusPlusrouting pathsformessagesfromTCP/IPhosts
whichcontainDestination Indexes1through 249 decimal.
The bridge is shipped with defaultModbusPlusrouting pathsforDestination
Indexesas showninTable 17.
Table 17 TCP/IPtoModbusPlusDefaultMapping
DestinationIndex (dest_idx) ModbusPlusRouting Path
1... 64 1.0.0.0.0... 64.0.0.0.0
65 ... 128 2.1.0.0.0... 2.64.0.0.0
129 ... 192 3.1.0.0.0... 3.64.0.0.0
193 ... 249 3.2.1.0.0... 3.2.57.0.0
Forexample, the defaultentryinfieldMBP_1 specifiesthatTCP/IPmessages
intended fordest_idx value1will be routed toModbusPlusnode 1 on the local
ModbusPlusnetwork(the same networkthatcontainsthe bridge).
Figure15showsan example of the bridge’sdefaultmapping,withone custom
entrymade bythe user.