User guide

Communication Capabiliites
890 USE 108 00 August 2001 97
Direct, Explicit, and Implicit Attaches
Modbus to
Modbus Plus
Address
Conversion
The manner in which Modbus Plus converts a Modbus message using bridge mode
is determined by the range of the Modbus address (1 ... 255):
This shows the address location and the various attach states.
If the address range in the Modbus message is between 1 ... 64, the message is
routed to the corresponding Modbus Plus node address on the local network. This
routing procedure is called direct attach address. Direct attach address routing
implies that a nonzero value exists in only routing address 1 in the Modbus Plus
message frame; it does not allow you to send the incoming Modbus message
beyond the local network.
255
80
79
70
69
65
64
1
0
Implicit Attach
Address
Explicit Attach
Address
Reserved
Direct Attach
Address
Reserved