Technical data

More About Oscilloscope Commands 37
Agilent InfiniiVision 2000 X-Series Oscilloscopes Programmer's Guide 795
All numbers must be strings of ASCII characters. Thus, when sending the
number 9, you would send a byte representing the ASCII code for the
character 9 (which is 57). A three- digit number like 102 would take up
three bytes (ASCII codes 49, 48, and 50). This is handled automatically
when you include the entire instruction in a string.
Duplicate Mnemonics
Identical function mnemonics can be used in more than one subsystem.
For example, the function mnemonic RANGe may be used to change the
vertical range or to change the horizontal range:
:CHANnel1:RANGe .4
Sets the vertical range of channel 1 to 0.4 volts full scale.
:TIMebase:RANGe 1
Sets the horizontal time base to 1 second full scale.
:CHANnel1 and :TIMebase are subsystem selectors and determine which
range is being modified.
Tree Traversal Rules and Multiple Commands
Command headers are created by traversing down the command tree. A
legal command header would be :TIMebase:RANGe. This is referred to as a
compound header. A compound header is a header made of two or more
mnemonics separated by colons. The mnemonic created contains no
spaces.
The following rules apply to traversing the tree:
• A leading colon (<NL> or EOI true on the last byte) places the parser at
the root of the command tree. A leading colon is a colon that is the
first character of a program header. Executing a subsystem command
lets you access that subsystem until a leading colon or a program
message terminator (<NL>) or EOI true is found.
• In the command tree, use the last mnemonic in the compound header
as the reference point (for example, RANGe). Then find the last colon
above that mnemonic (TIMebase:). That is the point where the parser
resides. Any command below that point can be sent within the current
program message without sending the mnemonics which appear above
them (for example, POSition).
The output statements in the examples are written using the Agilent VISA
COM library in Visual Basic. The quoted string is placed on the bus,
followed by a carriage return and linefeed (CRLF).
To execute more than one function within the same subsystem, separate
the functions with a semicolon (;):