NI Signal Element

Modified on 2018/08/03 20:55 by Administrator — Categorized as: Elements, Signal Acquisition

Summary

Element Icon NI Signal
Info
Category: Signal Acquisition AddIn: AddIn_NI
Creator: OkazoLab Scope: Experiment
Owns Snippets: None Usage: Snippets

Properties

NameDescription                              ConstraintsTypeOn
runtime
change
NI Settings
Sampling Rate        Defines the sampling rate (samples per second) of data acquisition. The value must be supported by the NI card.        
Design Time..
        		Double         
Voltage Range        Defines the expected voltage range of the analog signal. The voltage range must be supported by the NI card.        
Normal..
        		clRange         
Terminal Configuration        Defines the terminal congifuration for analog channels. Use 'Auto' unless you are sure that you need a different option        
Normal..
        		Int32         
Buffer Size        Defines the size of a circular buffer (in samples) for storing the incoming signal data.        
Design Time..
        		Int32         
Signal Generator
Signal Source        Defines a source for the signal. The emulated rhythmes can be used for offline validation of the chosen analysis settings        
Design Time..
        		enEmul..         
Emulated Sampling Rate        Defines the emulation sampling rate (samples per second), when data is generated or streamed from a file.        
Design Time..
        		Double         
Primary Frequency        Defines the frequency of the primary rhythm in the generated signal, in Hz. Assign the zero to exclude the primary frequency from the generated signal.        
Design Time..
        		Double         
Secondary Frequency        Defines the frequency of the secondary rhythm in the generated signal, in Hz. The secondary frequency magnitude is a half of the primary frequency magnitude. Assign the zero to exclude the secondary frequency from the generated signal.        
Design Time..
        		Double         
Noise Level        Defines the noise level (in % to the norm magnitude of the primary frequency). The noise is added to the generated signal. Assign the zero the exclude the noise from the generated signal.        
Design Time..
        		Double         
External Datafile        Opens the dialog for selecting a data file containing a stream of double numbers representing a signal. If a file name without a path is defined, the data file will be picked up in the location of the experiment file.        
Design Time..
        		String         
Channel Configuration
Selected Channels        Defines what signal channels are selected for acquisition within EventIDE. Selected channels are registered in the EventIDE signal pool at runtime and become available for the signal analysis elements.        
Design Time..
        		IList         
Selected Channel Count        Indicates how many signal channels are currently selected for acquisition        
Status..
        		Int32         
Total Channel Count        Indicates how many signal channels are available for acquisition in the total        
Status..
        		Int32         
Runtime Control
Reset Signals Now        Runtime commands that resets the signal buffers and data acquisition        
Runtime Command..
        		Boolean         
Control
Is Enabled        If set to false the element is completely omitted when the experiment is run        
Design Time..
        		Boolean         
Title        Title of the element        
Design Time..
        		String         

NI Signal Element allows signal acquisition via analog ports on National Instruments DAQ cards.


Description

The NI Signal element is capable of reading an arbitrary signal conveyed through the selected analog port on a NI DAQ card. As an experiment starts, the element begins receiving data and buffering samples into circular buffers, maintained by EventIDE (the buffers can collect data from multiple signal acquisition elements). The signal processing elements, e.g. Signal Analyzer element can be then used to monitor and analyze the buffered signals at runtime. Fast buffering and processing time in EventIDE (down to 1ms) allows instant detection of signal characteristics and, subsequently, various forms of signal-based feedback control in experiment.

Snapshots

Using the NI Max utility for emulation an analog signal

Using the NI Max utility for emulation an analog signal


Practical Use

  1. Add a new NI Signal element to any event in your experiment (the element is global and works from the start to the end of experiment).
  2. Select the added element to browse its properties in the Property panel.
  3. Select the NI analog port via the 'Analog Channel' property.
  4. Set the sampling rate of acquisition via the corresponding property. Refer to the NI documentation to chose the value supported by your card.
  5. If you have no NI card installed, you can still test the element using the NI Max utility (included in NIDAQ-mx), which can emulate a presence of the NI card in the system and a test signal (see the snapshot above).
  6. Use the signal processing elements to access the buffered data.



Notes