Sweep value

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A Sweep value which will be set and applied to a device or a Module. Some Modules only have a single Sweep value which basically means that they do not increase the complexity or dimensionality of the measurement. Of course it much more interesting if a Module has several Sweep values for which a measurement is done.

Besides Sweep values, there exist Measurement values which are the values being read back from your devices. In some case the Sweep value and the Measurement value might be identical.

Modules having an own tab often allow the user to choose how the Sweep values are created.

Defining Sweep values

Typical arrangement of selection boxes for Sweep mode and Sweep value.

In order to define how the Sweep of a certain module is done, the Sweep mode and the Sweep value have to be adjusted. Most modules therefore have selection boxes labeled "Sweep mode" and "Sweep value". The Sweep mode defines which kind of value will be varied. For example, an SMU can vary "Voltage [V]" or "Current [A]".

The Sweep value defines the source of the values which will run through during the measuremnt. The unit of the Sweep value will be defined by the Sweep mode, e.g. Volt or Ampere in case of an SMU.


Types of Sweep values

Internal Sweep values

SweepEditor

The SweepEditor is tabular input dialog to create complex lists of Sweep values.

SweepBox

The SweepBox is a simple input field where you can place some comma separated values. This feature is of particular importance if strings [1] are needed as Sweep value.

SweepScript

The SweepScript allows you to load the Sweep values from a text file


External Sweep values

Sometimes it is needed to apply a Sweep value which has been created by another module. For example, one SMU sweeps through several voltages. A second SMU will apply exactly the same voltage at the same time in order to charge a substrate or a neighboring device to a defined reference voltage.

To choose a Sweep value from another module go to the selection box "Sweep value" and choose an entry starting with "Sweep value of...". Using external Sweep values can be understood as a kind of Master&Slave concept where the applied Sweep value of one module finally depends on the Sweep value of another module. By using the modules Calc and Condition more sophisticated relationships are possible.

External Measurement values

Another interesting option is to use a Measurement value from another module. This feature allows you to implement an interaction between the items of the sequencer. For example, the Sweep value Integration time of a Spectrometer could depend on the signal of a photodiode measured by a SMU. As the Measurement value is just available at the end of each measurement point, it needs at least two iterations before a Measurement value can be used as Sweep value. Often, one has to use a Loop module in the sequencer if the module providing the Measurement value has no own sequence of Sweep values.

A nice example is the setting "example_SinSound.set" which shows how to hand over a Sweep value which depends on the time past.