HP 8530A, Руководство по эксплуатации и программированию, Страница: 347 / 439

Programming Examples
Commands are executed in the sequence in which they are received by the receiver . When a
command is received, the syntax is checked, stored in the command queue , then executed.
Some commands , such as SING , free the processor for other tasks during the time that they
are executing. If time becomes available while such a command is executing, the process
of reading a command, syntax checking, storage in the command queue , and sometimes
overlapping execution continues until up to eight commands are stored for pending execution.
The second part of this example sends HP 8530A instructions that prompt a response from the
receiver . These are the query commands and the OUTPxxxx; commands . Refer the HP 8530A
K eyword Dictionary for more information.
OUTPUT 716;"STAR; OUTPACTI;"
ENTER 716; Freq
PRINT Freq
This will print the current value for Start Frequency .
Example 2: A ctive Function Output
This example executes a User Preset, then reads and prints the current values for seven
active functions . The value for any function that can be made the active function can be read
this way . Functions or settings that do not have an active function may be read using query
commands . (Refer to the end of Chapter 3 of the HP 8530A K eyword Dictionary for a list
query commands .)
The value of the current active function is output as a single ASCII value in the basic units of
the function. F or example:
OUTPUT Rec;"MARK1;OUTPACTI;"
ENTER Rec_data;Freq
When executed with a marker as the active function, the sequence (above) returns the
frequency (in Hertz) at the marker position.
The sequence AVERON; OUTPACTI; outputs the currently selected averaging factor . The
sequence ELED; OUTPACTI; returns the currently selected Electrical Delay value in seconds .
The title and various other user-dened labels can also be read over the HP-IB by making it the
active function, then reading the characters into a string variable . F or example:
OUTPUT Rec;"TITL; OUTPTITL;"
ENTER Rec_data; String$
This returns the current title as the active function. Note that the title , calibration kit label,
standard class label, standard label, and the user parameter label are enclosed in quotation
marks . The standard class assignments list does not include the quotation marks .
Example 3: Marker Data Output
This example prints the x and y axis values of a marker in any selected domain or format. A
single sweep with averaging (factor of 4) is taken before reading the marker . Then, the display
format is queried and appropriate units are printed for the y axis value . Next, the x axis value
is read and the selected domain is queried and appropriate units are printed for the x axis .
If the system is currently operating in either the HOLD or the CONTINU AL mode (see
STIMULUS menu), then the data is output immediately; if SINGLE, or NUMBER OF GROUPS
has been selected, then the data output operation waits until the specied number of sweeps
is complete . F or example , the following sequence selects the linear magnitude polar display ,
turns on averaging, and commands 17 groups of sweeps . When complete , marker 1 is turned
18-18 HP-IB Programming