LockIn - OE-FET/JISA GitHub Wiki

Reference: Lock-In Amplifiers

public abstract class LockIn extends VISADevice

Abstract class to define the standard functionality of lock-in amplifiers

This page has been generated from the JavaDoc of the abstract LockIn class. Its purpose is to provide an overview of the methods shared by all classes extending from it. Simply put, this page details the functions shared by all Lock-In Amplifier classes.

Abstract Methods

This section details methods that the abstract class LockIn requires all extending (non-abstract) classes to implement. That is to say for users of this library all LockIn based classes will provide these functions and for developers any LockIn derived class that you create must implement these (otherwise your class will not compile).

setRefMode

public abstract void setRefMode(RefMode mode) throws IOException, DeviceException

Sets whether the lock-in amplifier is to use an internal or external reference signal

  • Parameters: mode — INTERNAL or EXTERNAL

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

setOscFrequency

public abstract void setOscFrequency(double frequency) throws IOException, DeviceException

Sets the frequency of the internal oscillator of the amplifier (eg for internal reference)

  • Parameters: frequency — Frequency, in Hz

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

setOscPhase

public abstract void setOscPhase(double phase) throws IOException, DeviceException

Sets the phase of the internal oscillator

  • Parameters: phase — Phase, in degrees

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

setOscAmplitude

public abstract void setOscAmplitude(double level) throws IOException, DeviceException

Sets the amplitude of the internal oscillator output.

  • Parameters: level — Amplitude, in volts

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

setTimeConstant

public abstract void setTimeConstant(double seconds) throws IOException, DeviceException

Sets the time constant to use for locking onto a signal (or closest over-approximation for devices with discrete settings)

  • Parameters: seconds — Time constant, in seconds

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

getFrequency

public abstract double getFrequency() throws IOException, DeviceException

Returns the frequency of the reference signal

  • Returns: Frequency, in Hz

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

getRefPhase

public abstract double getRefPhase() throws IOException, DeviceException

Returns the phase of the reference signal

  • Returns: Phase, in degrees

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

getRefAmplitude

public abstract double getRefAmplitude() throws IOException, DeviceException

Returns the amplitude of the reference signal

  • Returns: Amplitude, in Volts

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

getLockedAmplitude

public abstract double getLockedAmplitude() throws IOException, DeviceException

Returns the amplitude of the signal component locked on to by the amplifier

  • Returns: Amplitude, in Volts

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

getTimeConstant

public abstract double getTimeConstant() throws IOException, DeviceException

Returns the set time constant, in seconds

  • Returns: Time constant, in seconds

  • Exceptions:

    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

Concrete Methods

These are methods that already have an implementation in LockIn, however you may wish to override them in a deriving class if that particular lock-in has a more efficient means of performing the same task.

waitForStableLock

public void waitForStableLock(double pctMargin, long duration) throws IOException, DeviceException

Halts the current thread (ie pauses the program) until the lock-in has a stable lock (ie the locked-on amplitude has remained within the given percentage margin for at least the specified number of milliseconds).

  • Parameters:

    • pctMargin — Percentage margin within which to consider amplitude constant

    • duration — Minimum duration to be considered stable, in milliseconds

  • Exceptions:
    • IOException — Upon communication error
    • DeviceException — Upon compatibility error
public void waitForStableLock() throws IOException, DeviceException

Halts the current thread (ie pauses the program) until the lock-in has a stable lock (ie the locked-on amplitude has not varied by more than 0.1% in 5 seconds).

  • Exceptions:
    • IOException — Upon communication error
    • DeviceException — Upon compatibility error

Enumerations and Subclasses

Structures used by the SMU class and extending classes.

RefMode

public enum RefMode

Enumeration of reference modes

  • INTERNAL - Internal referencing mode
  • EXTERNAL - External referencing mode