Advantech ADAM-6050 18-Channel Isolated Digital I/O Modbus TCP Module ADAM-6050-BE Scheda Tecnica

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ADAM-6000 Series User Manual
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Appendix B  Data Formats and I/O Range
B.1  ADAM-6000 Commands Data Formats
ADAM-6000 and ADAM-5000/TCP system accept a command/response 
form with the host computer. When systems are not transmitting they are 
in listen mode. The host issues a command to a system with a specified 
address and waits a certain amount of time for the system to respond. If 
no response arrives, a time-out aborts the sequence and returns control to 
the host. This chapter explains the structure of the commands with Mod-
bus/TCP protocol.
B.1.1 Command Structure
It is important to understand the encapsulation of a Modbus request or 
response carried on the Modbus/TCP network. A complete command is 
consisted of command head and command body. The command head is 
prefixed by six bytes and responded to pack Modbus format; the com-
mand body defines target device and requested action. Following exam-
ple will help you to realize this structure quickly.
Example:
If you want to read the first two values of ADAM-6017 (address: 
40001~40002), the request command should be: