Tektronix 2714, Programmer'S Manual

Page: 45 / 308

Instrument-Specific Message Structure
2714 & 2715 Programmer Manual
2–5
Units specify the unit of measure. Except in the case of decibels (dBs), only the
first letter of the units is used. Message context determines how the first letter is
interpreted. For instance, the command
FREq 10 M
is the same as
FREq 10 MHZ
For either command the
M
is interpreted as MHz because frequency corresponds
to the
FREq
command. In a similar manner, the letter
M
would indicate millisec-
onds when used within the
TIMe 10 M
command.
Engineering units can be appended to certain number arguments (
FREq 10E+6
is
the same as
FREq 10 MHZ
).
Commands such as
REFlvl
require the entire dB unit (dBmV, dBm, etc.) to
avoid confusion. You can place as many spaces as desired between the number
and its units.
Responses with numerical arguments DO NOT append units to the argument.
The programmer must keep track of the units, or use a query that responds with
the units currently in use (for instance, the
RLUnit?
query).
An argument is the value that a command, query, or response transfers to or from
its associated 2714 or 2715 setting(s). For instance, from the command
FREq 200 MHZ
the value of 200 MHz is transferred to the center frequency setting. Arguments
may be numbers (with or without units), characters, strings, or linked with a
colon (:). A block of binary data may comprise the argument of some waveform
commands and responses.
Number refers to a decimal number consisting of one or more digits. Three
number formats are possible:
nr1 Integer (no decimal point)
nr2 Floating point number (decimal point required)
nr3 Integer or floating point number in scientific notation
(2.0E+3 or 2.000E+3, for example, instead of 2000)
A character argument consists of one or more letters usually expressing a word
or mnemonic. For instance,
ON
and
OFF
are arguments for commands that control
2714 or 2715 functions such as
AREs
(auto resolution bandwidth).
Units
Argument
Number Argument
Character Argument