Examples For Modbustcp - Beckhoff BC9000 Documentation

Bus terminal controller for ethernet

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Fieldbus system

Here the offset always describes a word. Offset 0x0003 writes to the fourth word in the output process

image. The length indicates the number of words, and the Byte count is formed from the combination of all

the bytes that are to be written. Sample: 4 words - correspond to a byte count of 8

The data bytes contain the values for the analog outputs. In this example, two words are to be written. The

first word is to receive the value 0x3FFF, and the second word is to receive the value 0x7FFF.

Query

Byte name

Function code

Read start address high

Read start address low

Read length high

Read length low

Write start address high

Write start address low

Write length high

Write length low

Byte count

Data 1 high

Data 1 low

Data 2 high

Data 2 low

Response

The coupler replies with the start address and the length of the bytes to be transferred in Byte count. The

data information follows. In this example the first word contains 0x0038 while the second word contains

0x3F0B.