Keithley 2450 Reference Manual page 162

Model 2450 Interactive SourceMeter® Instrument Reference Manual Section 3: Functions and features
To measure current and return relative time and readings formatted as they appear on the front
panel, send the following command:
MEASure:CURRent? "testData", READ, REL, SOURFORM
Buffer storage is consistent whenever readings are taken. The parameters, such as REL and
SOURFORM, only affect what is included in the response. If you do not include parameters, the
command only returns the reading.
Using TSP commands to select a reading buffer:
To make a measurement and store the readings in a specific reading buffer, use the
smu.measure.read() function. If you do not specify a buffer when you use the
smu.measure.read() function, readings are stored in defbuffer1.
If you select another buffer and you want to store additional readings in the previously selected buffer,
you have to select the buffer again or the instrument will use the buffer you just selected.
To measure voltage and store the readings in the voltMeasBuffer, send the following commands:
smu.measure.func = smu.FUNC_DC_VOLTAGE
smu.measure.read(voltMeasBuffer)
To measure voltage, store the readings in the voltMeasBuffer, and print the last reading in the
buffer, send the following command:
print(smu.measure.read(voltMeasBuffer))
To measure current, store the readings in defbuffer1, and print the last reading in the buffer, send
the following commands:
smu.measure.func = smu.FUNC_DC_CURRENT
print(smu.measure.read())
Storing readings in buffers
Before you store readings, make sure the correct reading buffer is selected. See Selecting a buffer
(on page 3-15) for more information.
To store a reading from the front panel, perform any operation that instructs the instrument to make a
measurement. The buffer-fill-status indicators light up to indicate that the buffer is filling. Depending
on the size of the buffer, the lit indicator may be difficult to observe. When all four indicators are lit,
the buffer is completely filled. All of the indicators will never be lit as long as the number of readings
stored is less than the selected buffer capacity.
To stop storing readings in a buffer when you are taking continuous readings, select the Trigger mode
indicator and select the Manual Trigger Mode.
You can press and hold the Trigger key for about 3 seconds to display the trigger mode window.
Stored readings are lost when the instrument is turned off. Stored readings are also lost when you
resize a reading buffer.
2450-901-01 Rev. B/September 2013 3-17