Quick start guide to using NI MultiSim with NI myDAQ

For those of you who prefer to watch a video guide scroll to the bottom of the page.

This guide assumes that you have first installed NI MultiSim 13 and then installed NI ELVISmx 14.0 driver for the NI myDAQ. Note this software only works on windows, if you have Mac, however, then all is not lost you simply need to use bootcamp to install windows 8.1 first and then install MultiSim and ELVISmx.

Testing the install

If installed correctly the NI ELVISmx instrument launcher will open when you plug the myDAQ into the USB port. You can use this to directly test the operation of the myDAQ by opening the Digital Multimeter, attaching the probes to the base of the unit and measuring the resistance of a resistor. Note you need to press the run arrow to start making a measurement. Or use the Digital Writer with an LED connected between DIO7 and DGND. Or if you don’t have a Resistor or LED to hand, use the Digital Reader and wire one of the DIO to 5V.

1. Start Multisim
2. Select File > New and then NI myDAQ design in the New design window shown below
3. Click Create.

Create new design dialog

Building the RC circuit schematic model

Create the RC circuit shown below

RC Circuit Schematic Design

To place the components, resistor and capacitor, either right click and select place component, or click the place basic button in the toolbar.

To wire components hover over point where you wish to connect to, left click, then move to the location for the end of the wire and left click to finish.

You must ensure the following conditions are met:

1. AO_0 is used as the input source.
2. Analogue ground (AGND) is attached to the ground reference point of your circuit i.e. the bottom leg of the Capacitor.
3. AI_0+ is used to measure the input voltage
4. AI_1+ is used to measure the output voltage across the Capacitor
5. Remember all voltages are measured across two points. In this case we wish to measure with respect to ground so we connect AI_0- and AI_0- to analogue ground (AGND)

Simulating the frequency response of the circuit

1. Right Click on the function generator icon on the myDAC symbol and select NI myDAQ instrument enabled in simulation
2. Double click on the Bode Analyser icon, highlighted with a red circle below, on the myDAQ symbol. The Bode Analyser will open.
3. In the Instrument control Panel > Device select > Simulate NI myDAQ
4. Click the Run button in the Multisim toolbar or F5. The simulated frequency response will appear.

Bode Analyzer

Build the real circuit

Use the breadboard to create the simulated circuit. Make sure you make all the required ground connections as specified for the simulation model.

Measuring the frequency response of the real circuit in MultiSim

1. In the Bode Analyzer Instrument control Panel > Device select > myDAQ1 (NI myDAQ)
2. Then click the Run button from within the Bode Analyzer Instrument control Panel
3. The frequency response will be plotted.

This measured response should closely match the simulated response assuming to have used the correct component values.