User manual

Modbus/TCP 7-3
© 2011 Pyramid Solutions Inc. Publication PUB-AB7603-014
Modbus/TCP Addressing
The BridgeWay’s Input (IN) and Output (OUT) areas are set to a maximum size
of 500 bytes each. The Status assembly area is 128 bytes. When accessing these
areas, with Modbus commands, the addressing is done according to the following
tables.
Note: Input Status and Coil bits are mapped MSB first. i.e. Coil 1 corresponds bit
15 of the associated register.
Input
Register
Input Status Bit Address
15
14 13 12 11 10 9 ... 1 0
1 1234567 ...1516
2 17181920212223 ...3132
.....
250 3985 3986 3987 3988 3989 3990 3991 ... 3999 4000
Table 7-3 Input Addressing
Holding
Register
Coil Bit Address
15
14 13 12 11 10 9 ... 1 0
1025 16385 16386 16387 16388 16389 16390 16391 ... 16399 16400
1026 16401 16402 16403 16404 16405 16406 16407 ... 16415 16416
...
1274 20369 20370 20371 20372 20373 20374 20375 ... 20383 20384
Table 7-4 Output Addressing
Input
Register
Input Status Bit Address
15
14 13 12 11 10 9 ... 1 0
257 4097 4098 4099 4100 4101 4102 4103 ... 4111 4112
258 4113 4114 4115 4116 4117 4118 4119 ... 4127 4128
...
320 5105 5106 5107 5108 5109 5110 5111 ... 5119 5120
Table 7-5 Status Addressing