Fieldbus system
BC9000 and BC910074 Version: 4.0.0
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 Sample
Function code 23
Read start address high 0
Read start address low 0
Read length high 0
Read length low 2
Write start address high 8
Write start address low 0
Write length high 0
Write length low 2
Byte count 4
Data 1 high 63
Data 1 low 255
Data 2 high 127
Data 2 low 255
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.
Byte name Sample
Function code 23
Byte count 4
Data 1 high 0
Data 1 low 56
Data 2 high 63
Data 2 low 11
7.5.5 Examples for ModbusTCP
Examples for Modbus TCP are contained in this help text.
Simple example: Modbus TCP via VB6.0 https://infosys.beckhoff.com/content/1033/bc9000/Resources/
zip/4351427467.zip
Example: ModbusTCP via VB6.0, set and reset of the watchdog:https://infosys.beckhoff.com/content/1033/
bc9000/Resources/zip/4351429643.zip