7: TSP command reference  Series 2600B System SourceMeter® Instrument 
 
7-24  2600BS-901-01 Rev. C / August 2016 
 
Details 
The reading buffer fill count sets the number of readings to store before restarting at index 1. If the 
value is zero (0), then the capacity of the buffer is used. Use this attribute to control when the SMU 
restarts filling the buffer at index 1, rather than having it restart when the buffer is full.  
If the bufferVar.fillcount attribute is set to a value higher than the capacity of the buffer, after 
storing the element at the end of the buffer, the SMU will overwrite the reading at index 1, the reading 
after that will overwrite the reading at index 2, and so on. 
This attribute is only used when the bufferVar.fillmode attribute is set to smuX.FILL_WINDOW. 
For dedicated reading buffers, all buffer attributes are saved to nonvolatile memory only when the 
reading buffer is saved to nonvolatile memory. 
 
Example 
 
smua.nvbuffer1.fillcount = 50 
Sets fill count of dedicated reading 
buffer 1 (source-
measure unit (SMU) 
channel A) to 50. 
 
Also see 
bufferVar.fillmode (on page 7-24) 
 
bufferVar.fillmode 
This attribute sets the reading buffer fill mode. 
Type  TSP-Link accessible  Affected by  Where saved  Default value 
 
Usage 
fillMode = bufferVar.fillmode 
bufferVar.fillmode = fillMode 
 
The reading buffer fill mode; set to one of the following: 
•  0 or smuX.FILL_ONCE: Do not overwrite old data 
•  1 or smuX.FILL_WINDOW: New readings restart at index 1 after acquiring reading at 
index bufferVar
 
The reading buffer; can be a dynamically allocated buffer (user-defined), or a 
dedicated reading buffer (such as 
) 
 
Details 
When this attribute is set to smuX.FILL_ONCE, the reading buffer will not overwrite readings. If the 
buffer fills up, new readings will be discarded.  
When this attribute is set to smuX.FILL_WINDOW, new readings will be added after existing data until 
the buffer holds bufferVar.fillcount elements. Continuing the sequence, the next reading will 
overwrite the reading at index 1, the reading after that will overwrite the reading at index 2, and so on.  
For dedicated reading buffers, all buffer attributes are saved to nonvolatile memory only when the 
reading buffer is saved to nonvolatile memory.