Overview of NI Multisim Virtual Instruments

NI Multisim provides a number of virtual instruments that you can use to drive, measure and investigate your circuits' behavior. These instruments are set, used and read just like their real-world equivalents. They look just like the instruments you’ve seen and used in a real lab environment. Using virtual instruments is the easiest way to examine your circuit’s behavior and show the results of a simulation. In addition to the standard instruments that come with NI Multisim, you can create your own custom instruments using NI LabVIEW, a graphical development environment for creating flexible and scalable test, measurement, and control applications.

Introduction To Virtual Instruments

NI Multisim allows a user to place a virtual instrument from the Simulate > Instruments menu or directly from the instrument toolbar.

Virtual instruments have different views to it, to allow for selection, placement, wiring, change of settings, data display and so on.

Type	Description	View
Icon	Represents an instrument in NI Multisim's instrument toolbar
Symbol	Represents an instrument in a circuit Use the instrument's terminals to wire it to a circuit Double click on an instrument's symbol to open the instrument panel.
Panel	Allows user to interact with the instrument Set parameters Display data

You can show or hide the instrument panel by double-clicking on the instrument's symbol. The instrument panel is always drawn on top of the main workspace so that they are not hidden. You can place the instrument panel wherever you wish on your desktop and resize it in order to account for different screen resolutions and presentations modes. When you save your circuit, the instrument panel location and hide/show status are stored with the circuit. As well, any data contained in the instrument is saved, up to some maximum size.

 

Key Features Of Virtual Instruments

NI Multisim’s instruments are wired into the schematic just like you would connect a real instrument on the bench. You can even re-wire an instrument’s input while the simulation is running; giving you the same real world flexibility you have when attaching probes of oscilloscopes or multimeters to different test points of your circuit. Like their real world counterparts, they are fully interactive so that you can change their settings while a simulation is running and instantly see new results.

Virtual instruments let you take advantage of the full power of simulation without having to be an expert in SPICE syntax. When you press a button on an instrument, an appropriate simulation command is automatically issued and results are immediately displayed on that instrument's face. Instrument settings and simulation results can also be saved with the circuit file and the faceplates of instruments can be resized to adjust to different screen resolutions and presentations modes.

The NI Electronics Workbench Group has also partnered with leading instrument suppliers such as Agilent® and Tektronix® to provide simulated “real” instruments that look and operate exactly like these vendors ’ real--world models.

Key features that are shared by most virtual instruments

• Change settings while the simulation is running
• Re-wire terminal while simulation is running
• Use multiple instance of the same instrument in one circuit
• Save instrument settings and displayed data with the circuit file
• Populate displayed data in the Grapher View
• Resize instrument panel to account for screen resolution or presentation mode
• Easely export displayed data in TXT, LVM and TDM format

 

Categories Of Virtual Instruments

NI Multisim’s virtual instruments can be grouped into six categories:

Note: Pictures are reduced in size and quality. Full size picture can be found in the archive files in the Download section of this document.

AC and DC Instruments

Name	Function	Icon	Symbol	Panel
Function Generator	Sine, Triangular and Square wave Frequency Duty Cycle Amplitude Offset
Multimeter	AC and DC Current Voltage Resistance Decibel loss
2-Channel Oscilloscope	up to 2-Channels Y and X scaling Y offset Trigger Cursor
4- Channel Oscilloscope	up to 4-Channels Y and X scaling Y offset Trigger Cursor
Wattmeter	Power Measurement Power Factor
IV Analyzer	Diodes PNP BJT NPN BJT PMOS NMOS
Frequency Counter	Frequency Period Pulse Rise/fall time AC or DC coupling Trigger
Bode Plotter	Frequency response Gain and phase shift up to 10 GHz
Distortion Analyzer	Intermodulation distortion Total harmonic distortion

 

Digital and Logic Instruments

Name	Function	Icon	Symbol	Panel
Logic Analyzer	16-Channels Cursor Data History Trigger Internal/External clock
Logic Converter	Digital Circuit to Truth table and Boolean Expression Truth table to digital circuit Boolean expression to digital circuit
Word Generator	Cycle, burst and step updates Hex, DEC, Boolean and ASCII data view Timing Trigger

 

RF Instruments

Name	Function	Icon	Symbol	Panel
Spectrum Analyzer	Amplitude vs. frequency Signal components (Power and Frequency) Zero, full and custom span
Network Analyzer	Digital Circuit to Truth table and Boolean Expression Truth table to digital circuit Boolean expression to digital circuit

 

Simulated Vendor Instruments

Name	Function	Icon	Symbol	Panel
Agilent Waveform Generator	Type: 33120A Reflects the behavior of the real instruments
Agilent DMM	Type: 34401A Reflects the behavior of the real instruments
Agilent Oscilloscope	Type: 54622D Reflects the behavior of the real instruments
Tektronix Oscilloscope	Type: TDS 2024 Reflects the behavior of the real instruments

 

Measurement Probes

Name	Function	Icon	Symbol	Panel
Dynamic Probe	Current, voltages and frequency Referenced to circuit GND Fixed to a net or at mouse cursor Triggers events
Referenced Probe	Current, voltages and frequency Referenced to any other probe Fixed to a net Triggers events
Current Probe	Emulates the behavior of industrial clamp-on current probes Various Voltage to Current ratios			Use standard virtual instruments to display data Oscilloscope Multimeter etc.

 

NI LabVIEW Based Instruments

Name	Function	Icon	Symbol	Panel
LabVIEW Microphone	Interface with your PCs sound devices Recording length Sample rate
LabVIEW Speaker	Interface with your PCs sound devices Update rate
LabVIEW Signal Analyzer	Time domain signal Auto power spectrum Running average
LabVIEW Signal Generator	Sine, Triangular, Square and Sawtooth Frequency Duty Cycle Amplitude Offset Phase

 

Custom NI LabVIEW based Instruments

Create your own custom instruments using the NI LabVIEW graphical development environment. Instruments can include real world data acquisition, instrument control via GPIB or RS232, mathematical analysis, and so on. Download any of the following custom NI LabVIEW based instruments and use them with your simulation.

Name	Function	Icon	Symbol	Panel
LabVIEW Expression Source	Enter mathematical expressions Drag & drop support Syntax check
LabVIEW DAQ Source	Input from NI DAQ devices Up to 4 analog input channels
LabVIEW GPIB Source	Interface to any GPIB device Edit received data Parse received data Save GPIB commands with circuit
LabVIEW Comparison Display	Display the difference of two input channels Define minuend and subtrahend (A-B and B-A) Normalize on any input channel
LabVIEW Phasor Display	Oscilloscope projection of the phasors Phase measurements Up to 3 AC signals
LabVIEW Elevator Display	3 levels Set trigger voltage Set elevator speed
LabVIEW Voltage Output	Output to NI DAQ devices Software timed update rate Up to 2 analog output channels

 

Additional Resources

Download “How to..” examples for NI Multisim Virtual Instruments

Download NI LabVIEW based instruments for integration of real world I/O, signal comparison, and custom displays

View Tutorial on “How To Create a LabVIEW Based Virtual Instrument For NI Multisim”

View the “NI Circuit Design Technical Library” for more examples, tutorials and resources

Learn which Virtual Instruments are available in the professional editions of NI Multisim

Learn which Virtual Instruments are available in the academic editions of NI Multisim

 

Note: Pictures are reduced in size and quality. Download the archive files below for full size pictures. Please link to http://www.ni.com/multisim or http://ni.com/academic/circuits if you intend to use any of the pictures for documentation, tutorials, web pages, etc..

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