User's Manual

CHAPTER 3
Serial communication protocol
19
2. Select the appropriate serial port and click OK.
3. Configure your terminal as follows:
• 19200 baud
• 1 stop bit
• 8 data bits
• No parity
• No protocol (neither hardware nor software)
4. Select OK to open the terminal window.
5. Press Enter to generate a response in the window.
Serial communication protocol
This protocol is based on a master sending commands and a node
answering; the whole communication is conducted in plain ASCII,
as strings. When exchanging numbers, they are represented in
decimal format. All commands are terminated with a CR/LF combi-
nation. All responses (answers) are terminated with the # character.
General format of a command
The commands have the following format:
ID Command Param1 Param2 ... ParamN
• ID is the destination device. If you include an ID as part of a
command, the node checks whether ID=ownID. If it does,
the node executes the command on itself. If the ID is not the
node’s ID, the node executes the command on a remote
device, if such an ID exists. If the ID is missing, this implies
that the command is addressed locally.
Note: Not all the commands can be relayed remotely.
• Command is the command proper, which can be composed of
a variable string of characters (for example, SLOT). Each node
can implement a set of commands depending on the
functionality of the node itself. However, as a minimum
requirement, a node recognizes the CMDS command, which
returns a list with the commands accepted by the node.
• Param1 Param2 ... ParamN represent the parameters,
which are command dependent. If you type no parameters
when you issue a command, it is the equivalent of querying