Keithley 2600a series - Programming Overview; What Is a Chunk; What Is a Script

2600AS-901-01 Rev. B / September 2008 Return to Section Topics 12-5
Series 2600A System SourceMeter® Instruments Reference Manual Section 12: TSP Fundamentals and Script Management
creates it is executed. In this case the chunk that creates it is a script. Therefore, the function will
not exist until the script that creates it is executed. This is often confusing to first time users.
Example: Create the function MyFunction with a script named MakeMyFunction. The sequence of
messages to do this is shown as follows:
loadscript MakeMyFunction
MyFunction = function (who)
print("Hello " .. who) -- The .. operator concatenates two strings.
end
endscript
After this sequence of messages is sent, the MakeMyFunction script exists on the instrument in a
global variable named
MakeMyFunction. The MyFunction function however does not yet exist
because we have not executed the
MakeMyFunction script. Let us now send the message
MakeMyFunction(). That message instructs the instrument to run the MakeMyFunction script
which then creates the
MyFunction global variable that happens to be a function.
If we now send the message MyFunction("world"), the instrument will execute the MyFunction
function, which causes the instrument to generate a response message with the text “Hello world”
in it.
Programming overview
What is a chunk?
A chunk is a single programming statement or a sequence of statements that are executed
sequentially. There are non-scripted chunks and scripted chunks.
Single statement chunk: The following programming statement is a chunk:
print("This is a chunk")
When the above chunk is executed, it returns the following string:
This is a chunk
Multiple statement chunk: A chunk can also contain multiple statements. Each statement in the
line of code is to be separated by white space. The following chunk contains two statements:
print("This is a chunk") print("that has two statements")
When the above chunk is executed, the two statements are executed sequentially and the
following strings are returned:
This is a chunk
that has two statements
Multiple chunks: When sent separately, the following two lines of code are two separate chunks.
The first chunk sets the source level of SMU A to 1V and the second chunk turns the output on.
smua.source.levelv = 1
smua.source.output = smua.OUTPUT_ON
Scripted chunk: In a script environment, the chunk is the entire listing of test programming code.
If the two statements in the above example were created as a script, then those two lines of code
would be considered one chunk. See the topic below,
What is a script?
What is a script?
The Series 2600A utilizes a Test Script Processor (TSP) to process and run individual chunks or
programs called “scripts”. A script is a collection of instrument control commands and