CHAPTER 3
Performing Advanced Functions
20
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
strings. When exchanging numbers, they are represented in deci-
mal format. All commands are terminated with a CR/LF combina-
tion. 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. Not naming any ID implies that the
command is addressed locally.
Note: Not all the commands can be executed 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
for information (the
GET
version of a command). If you type
parameters, you are issuing the
SET
version of a command
and are setting the command to the parameters you typed.
General format of an answer
The answers have the following format:
ID Command Result1 Result2 ... ResultN ErrResult
#