The NI LabVIEW Multisim API Toolkit has been developed for the LabVIEW environment and provides access to more than 120 functions to automate the simulation of a Multisim circuit from LabVIEW. This toolkit is an innovative new connection between the worlds of design and graphical programming. You can for automate simulations easily from a graphical programming language, to:
• Access simulated measurements within the LabVIEW environment for further, domain specific analysis
• Correlate simulated and real measurements in a single LabVIEW environment
• Use simulated measurements as a design under test (DUT), in order to build test/validate cases earlier in the design flow
Multisim allows engineers to use simulation to optimize the performance of designs earlier in the design flow and ensure circuits meet specifications with fewer prototype iterations. The LabVIEW Multisim API toolkit added in Multisim 13.0 enables designers of analog and mixed-mode circuits to easily create graphical program in LabVIEW that rapidly perform or automate critical design tasks which is impossible in other simulation tools. Some of the critical types of analyses that are available include:
Multisim natively provides an Application Programming Interface (API) that allows for the automation of circuit simulation and analyses through a COM interface that designers can use to programmatically control.
The LabVIEW Multisim API Toolkit is a collection of VIs that makes the Multisim API ready-to-use for LabVIEW users. With this API toolkit users can take advantage of over 120 ready-to-use LabVIEW Virtual Instruments (VIs) to:
The LabVIEW Multisim API Toolkit is installed automatically with Multisim 13
This example uses theLabVIEW Multisim API Toolkit to iterate through multiple critical values in a circuit in an automated fashion to assist us in calculating efficiency. Without a toolkit such as this one in LabVIEW an individual would try to optimize efficiency by manually changing values in a circuit and recording the simulated value in each. This is time consuming and error-prone.
Our goal for this example will therefore be to set the switching frequency of parameters on a buck converter based on NXP components and then perform a sweep across several switching frequency, Fsw, values. For each step a transient analysis is run and the efficiency of the circuit is automatically calculated. This can all then be plotted and the best switching frequency will be observed through this process.
Using the circuit parameters (click here to learn more about circuit parameters) and toolkit we can step through the development of this test.
All the example files are attached to this document in the folder called apidemo.zip
By using this approach we can clearly see the various efficiency values of our circuit. The best option can be chosen and we have been able to automate what has traditionally been a complex and error-heavy process.
In this example a signal conditioning circuit is designed in Multisim to filter acquired heartbeat signals for the development of a biomedical device application.
The circuit is a single stage active filter using operational amplifiers from Texas Instruments. While the heart beat signals are real-world signals that could be acquired using a sensor device or simulated using the LabVIEW Biomedical Toolkit.
All the design files of this example are in the attached file sigcond.rar
As you can see the transient simulation in Multisim could be used to evaluate whether the chosen op-amp will provide the desired filtering response or not for this low-voltage signal. However, for the purpose of this design, the LabVIEW Multisim API Toolkit is leveraged to automate multiple simulation runs that:
The application below is written in LabVIEW. You can simply download and run main.vi under the project Heart Beat Signal Conditioning.lvproj.
As you can see using this automation code multiple output plots for different op-amps and input signals have been very easily created. Also the table on top of the graph indicates the different corresponding SNR values. Without the automation of LabVIEW this toolkit provides, such calculation would a separate simulation run for each case which is a lengthy process.
Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.