Installation guide
196 Message Routing
890 USE 100 00
B .4 Bridge Multiplexer Routing
Modbus Address Map
If a Modbus message is received at a BM85 Modbus port, the address
(1 ... 255) is compared to an internal Modbus Address Map table for the
port. The map table contains up to 64 addresses, each pointing to a
fivebyte routing path. If an address match is found in the table, the
routing path is applied to the message. If the first byte is in the range
1 ... 64, the message is routed out on Modbus Plus. If the first byte is
zero, the message goes to a Modbus port (1 ... 4) specified in byte two.
If that port has a single slave device, the remaining three routing bytes
should be zeros. If the port has a network of slave devices, byte three is
the slave address.
If a match is not found in the table, address conversion proceeds as in
Figure 76.
RESERVED
RESERVED
0
1
64
65
79
80
255
DIRECT
ATTACH
ADDRESS
MUX ATTACH
ADDRESS
IMPLICIT
ATTACH
ADDRESS
70
71
74
75
RESERVED
NOTE:
ADDRESSES 65 ... 79 ARE ALL
RESERVED FOR BM85 PORTS
THAT ARE CONFIGURED IN THE
SILENT MASTER MODE.
Figure 76 Bridge Multiplexer Address Conversion