How To Crack Multisim 14.3

[Adimar Poynter]

Isit possible to change the simulation steps in multisim? (more exact and more detailed simulation results). I have an output that changes quite fast in time, so at the moment the measurements are very rough and unrefined

Yes, I believe so. It took me a minute to find this myself. Go to the area where you hit the "Play" icon to start the simulation. It will say "Interactive" to the right. Click on that. Under the "Interactive Simulation" option, Analysis Parameters tab, (you will already be at that tab by default), check the box for "Maximum time step (TMAX)".

Change this number to change how fast the simulation runs. This will set how many seconds each time step represents. This means that TMAX of 1 second will be very fast (each step moves through one second of simulated time). If you set it to something slower like .00001, that might work. I found 1e-006 to be a good setting.

I'm attempting to prevent students from copying multisim files from each other. LabVIEW has a revision tracking feature for VIs which has been very helpful at catching cheaters. Does Multisim has such a feature? or some other method of determining file user origination/modification data?

Multisim doesn't have a revision history for circuits, but there is some information about the file you can get under the File > File Information option.

You may also set a variety of global- and circuit-restrictions from the Options menu, but none of these provide a revision history

I am trying to convert a series of student labs for a dynamic systems course to run on a newer, better setup. Previously, the lab I am working on took input from a sensor, fed that input through an analog circuit, and fed the output from that circuit into a Labview VI. My question is, can that be done using a Multisim simulation instead of a physical circuit? I have found volumes regarding running Labview VIs in Multisim, but nothing regarding a VI taking input from a Multisim circuit. If this can be done, what configuration would you suggest?

1. If you want to use a standard Multisim circuit you can feed I/O to Multisim via the LabVIEW Multisim Connectivity Toolkit... You'll need to program the LabVIEW application to communicate with Multisim and you can write sensor or other voltage/current stimuli to sources within the Multisim circuit via the API. The tool allows you to read the simulation data (by sampling voltage and current probes) which creates a waveform (and then you can process using LabVIEW).

2. If you want everything run and controlled via Multisim, you can create LabVIEW VIs (input, output, or inout) that will run synchronously inside of Multisim. You can create .llbs based on templates and then add functions that will allow you to create measurements, etc...

Thank you very much, I tried the second option and got the equivalent of my original VI to run in Multisim. However, the system as a whole doesn't seem to like my myDAQ. When I made a new Multisim VI to acquire input from the myDAQ, it doesn't register in Multisim under the Simulate tab where the other instruments I've made have. Do I have to do something special to interface a myDAQ with Multisim?

It is likely due to the fact that some of the vi.lib or DAQ driver libraries that you need to link into the VI are missing in the build of your Multisim LabVIEW .llb. If Multisim cannot locate missing subVIs (from vi.lib or elsewhere) Multisim will not load the LabVIEW VIs that you have built. Sometimes you need to include these vi.lib subVIs (usually contained in a LabVIEW library - lvlib) in the project build (by default all vi.lib functions are excluded). When Multisim loads, it loads in the appropriate base level LabVIEW functionality only - this includes most LabVIEW functions, basic math, etc - however any advanced measurments or additional toolkits or drivers need to be included in the .llb build or the support folder directly.

Here is a sampling of a recent project that I used that included some advanced measurement VIs in LabVIEW. I believe the only ones included by default in Multisim are the 'Base' lvlibs (which does include most of the LV functionality, but for my application advanced measurements were needed).

Note that it will take some additional time to build (since when LabVIEW builds your llb it will search all of the lvlibs for VIs that it thinks are in your application and then remove the ones that are not)... but your VI should then run in Multisim...

Here you can explicitely call the lvlibs to be included in your build and then take out functions you don't need (but you may not know what subVIs are used if they are embedded in lvlibs that you're not aware you are using (such as the case with Express VIs) ). You also have to be careful since I have found out the hard way that menus within the lvlibs cannot be included in .llbs, so you have to exclude any menus folders within the lvlibs (you can include/exclude pieces of lvlibs by the way)... Sometimes this can reduce the build time, but it can be a little trickier since you need to know which things to include/exclude. If you are just beginning, use method #1 at first.

Ok thats they way it is with most Multisim VIs that I am familiar with but there may be some things that I am missing because you are using myDAQ... I've requested that someone familiar with the myDAQ products on the academic team also reply to this thread.

My Dependencies +/- includes some 100+ subVIs (almost all DAQmx related), and every build configuration I've tried results in a directory of (only) a dozen or so. I've tracked down the subVIs required and copied them to the same folder as the rest of the unbuilt VI, but haven't seen any way to include them in the Build process. How would I call a specific set of directories to be included in the build?

Hi, I have some experience building LV Instruments to be used within Multisim, but I have never built a myDAQ VI in Multisim. If I create a LV Instrument that takes an analog input from channel 0 on the myDAQ, and this signal is fed into the simulation... would that be a good starting point for you?

BTW... my guess is that there is some error in the VI you have created, rather than missing VIs in the build process, unless your VI is used in a computer where LabVIEW, DAQmx and myDAQ are NOT installed. If the latter is the case, then you DO need to include all necessary VIs. But if you are going to run your VI in Multisim, in a computer that has LabVIEW, DAQmx and myDAQ installed, you should not need to include those VIs.

When a VI that you have built for Multisim has some sort of error, Multisim is unable to load it at startup, and simply does not shows up in the Instruments toolbar. Typical errors are related to the multisimInformation file and info not correlating to the main template VI, or some execution error on the main template VI.

I'm running this on a machine with LabVIEW, DAQmx, and myDAQ installed. That said, creating that theoretically simple sample VI would be fantastic. My current approach involves following the tutorial user32 posted earlier in this thread, but starting with the Output folder and making a different .vit file. Currently, in the case structure for "update initial output data", I have a flat sequence structure with the DAQ assistant subVI in one compartment and the Bundle by Name and Send Notification subVIs in the other. I'm sure I'm forgetting to do something critical during or before the build process, but for the life of me can't figure out what.

It seems that you do need to "include" vi.lib, otherwise Multisim cannot load the full VI at startup... so uncheck "exclude vi.lib" from the build settings. I'm attaching the whole project and LLB. Build the final instrument LLB from the project and try it out yourself. This simple VI acquires signals from the analog channel 0. I used the starter output template used in Multisim and just added the myDAQ related VI to acquire signals.

So, download the attachment, build the project and give a test. The way I configured the Build Settings, will include all DAQmx related VIs within the final LLB. I've seen cases in which Multisim does needs to add those VIs and others in which not. I recently finished a Keithley 2000 DMM driver to be used within Multisim and it did not required any of the GPIB VIs to be saved with the instrument. So, is just a matter of trial and error depending on what those VIs depend on.

Hi all! For multisim 14, I notice that the "transient analysis" using the function generator (in squarewave out mode and triangular output mode) provides results up to a certain amount of time, but the results eventually just cut-out (goes to zero)....eg such as after 0.1 seconds.

I've attached a screenshot of my basic (mosfet) circuit schematic, and a multisim14 project file, and a screenshot of my simulation graph file (which shows that the simulation just drops and flatlines at zero after a relatively short amount of time).

I notice that the simulations will cut-out (bomb out) when the function generator is in squarewave output mode and in triangular wave output mode.... while no issue occurs when the generator is in sinewave output mode.

It is a transient analysis, but I'm expecting that the 50 Hertz current should not just disappear at 100 millisecond. I'm expecting that current signal (having a 50 Hz frequency) should just continue in time, and not just vanish at 100 millisecond.

But, when I deleted (removed) the tektronix oscilloscope from the schematic (virtual circuit), the simulation bombed out at approximately 1.4 seconds. That is, the simulated waveform I(L1) dropped (permanently) to zero at 1.4 second, which is at least better than 100 millisecond. But the issue was still there. The simulation was still bombing out.

But, when I went back to the original schematic again, and then bypassed (shorted) the 1 Ohm resistor (that was originally in series with inductor L1), the transient analysis simulation worked properly (ie. behaved normally up to the user-specified simulation time).

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