MESSAGES AND COMMUNICATION
PROTOCOL
Command Separator
A message consists of one command or a series of com-
mands, followed by a message terminator. Messages con-
sisting of multiple commands must have the commands
separated by semicolons. A semicolon at the end of
a
mes-
sage is optional. For example, each line below is a message.
l
N IT
TEST; 1NlT;RQS 0N;USER OFF;ID?;SET?
TEST;
Message Terminator
Messages may be terminated with EOI or the ASCll line
feed (LF) character. Some controllers assert EOI concur-
rently with the last data byte; others use only the LF charac-
ter as a terminator. The instrument can be internally set to
accept either terminator. With EOI ONLY selected as the
terminator, the instrument interprets a data byte received
with
€01 asserted as the end of the input message; it also
asserts EOI concurrently with the last byte of the output
message. With the LFIEOI setting, the instrument interprets
the LF character without
EOI
asserted (or any data byte
received with EOI asserted) as the end of an input message;
it transmits carriage return
(CR)
followed by line feed (the LF
with EOI asserted) to terminate output messages. Refer
service personnel to the Maintenance section of the manual
for information on setting the message terminator. TM 5000
instruments are shipped with EOI ONLY selected.
Formatting
A
Message
Commands sent to TM 5000 instruments must have the
proper format (syntax) to be understood; however, this for-
mat is flexible in that many variations are acceptable. The
following describes this format and the acceptable
variations.
The instruments expect all commands to be encoded in
ASCII; however, they accept both upper and lower case
ASCll characters. All data output is in upper case. See Fig.
3-2.
As previously discussed, a command consists of a head-
er followed, if necessary, by arguments. A command with
arguments must have a header delimiter which is the space
character SP between the header and the argument. The
space character
,+,, carriage return
,,,
and line feed
,,
are
shown as subscripts in the following examples.
RQSs,ON
If extra formatting characters SP, CR, and LF (the LF
cannot be used for format in the LFIEOI terminator mode)
are added between the header delimiter and the argument,
they are ignored by the instrument.
Example
1
:
RQSs,ON;
Example
2:
ROSS,
,,
ON;
Example
3:
ROSS,
,,
,,
,, ,,
ON
In general, these formatting characters are ignored after
any delimiter and the beginning and end of a message.
In the command list, some headers and arguments are
listed in two forms, a full-length version and an abbreviated
version. The instrument accepts any header or argument
containing at least the characters listed in the short form;
any characters added to the abbreviated version must be
those given in the full-length version. For documentation of
programs, the user may add alpha characters to the
full-
length version. Alpha characters may also be added to que-
ry header, provided the question mark is at the end.
USER?
USERE?
USEREQ?
USEREQUEST?
Multiple arguments are separated by a comma; however,
the instrument will also accept a space or spaces as a
delimiter.
NOTE
In the last example, the space is treated as a format
character because it follows the comma (the argument
delimiter).
Number Formats
The instrument accepts the following kinds of numbers
for any of the numeric arguments.
Signed or unsigned integers (including
+O
and -0).
Unsigned integers are interpreted as positive.
Examples: +1,
2,
-1, -10.
To Next Page
Loading...
Need help?
General
