B&B Electronics ADAM-6066 - Manual - Manual (Page 232)

ADAM-6000 Series User Manual 222
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: