
Keysight M8070A Programming Guide
89
SCPI Command Language
4
Definite Length Arbitrary Block Data
Block data is used when a large quantity of related data is being returned.
A definite length block is suitable for sending blocks of 8-bit binary
information when the length is known beforehand. An indefinite length
block is suitable for sending blocks of 8-bit binary information when the
length is not known beforehand or when computing the length beforehand
is undesirable.
It has the following format:
#<Length of length><Length of data><data>
<Length of length> is a single integer that contains the number of digits in
<Length of data>, which in turn contains the length of the data. For
example, a 512-byte pattern would be defined as:
#3512<data>
Important Points about SCPI
Important Points about SCPI - Concepts
There are a number of key areas to consider when using SCPI for the first
time. These are as follows:
• Instrument Model
• Command Syntax
• Optional Parts of Commands
• Sending Commands
• Command Separators
• SCPI Command Structure
Instrument Model
SCPI guidelines require that the M8020A/M8030A/M8040A is compatible
with an instrument model. This ensures that when using SCPI, functional
compatibility is achieved between instruments that perform the same
tasks. For example, if two different instruments have a programmable
clock frequency setting, then both instruments would use the same SCPI
commands to set their frequency. The instrument model is made up of a
number of subsystems.
The sub-system defines a group of functions within a module and has a
unique identifier under SCPI, which is called the Root Keyword.