6243/44 DC Voltage Current Source/Monitor Operation Manual
5.2.5 Message Exchange Protocol
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5.2.5
Message Exchange Protocol
The 6243/44 receives program messages and issues response data from and to the controller and other
devices through the GPIB bus. Program messages comprise commands and queries (“query” refers in par-
ticular to commands that ask for response data in return). The exchange of these data follows a specific
procedure. This procedure is explained in the following.
(1) GPIB buffer types
The 6243/44 has the following two buffers.
(a) Input buffer
This is a buffer for temporarily storing data for command analysis. (It accommodates 255 bytes
and input above this generates an error.)
The input buffer is cleared by either of the following methods.
• Turn OFF and ON the power.
• Execute DCL or SDC.
(b) Output buffer
Buffer for storing data until read from the controller. (Accommodates 255 bytes.)
The output buffer is cleared by either of the following methods.
• Turn OFF and ON the power.
• Execute DCL or SDC.
5.2.6
Command Syntax
The command syntax is defined by the following format.
(1) Header
The header normally contains the common command header and the simple header.
The common command header has an asterisk (*) placed in front of the mnemonic.
The Simple headers do not have hierarchical structure and are functionally independent commands.
Placing a question mark (?) right after the English characters in the header makes the command into
a query command.
(2) Space (blank character)
One or more spaces can be used. (Spaces may be omitted.)
(3) Data
If the command requires multiple data sets, multiple data sets are separated by comma (,). A space
may be used directly before or after a comma (,). For details on the data types, refer to Section 5.2.7,
“Data Format.”
(4) Description of multiple commands
The 6243/44 allows multiple commands to be described consecutively or separated by semicolon (;),
comma (,) or space (_) on one line.
Header
Space (blank character)
Data
