Thankfully, LTSpice generates data when doing a transient analysis with multiple stepping parameters fairly easily. One of those flavors is the ability to include a list of values for your variable name. Is there a trick I can use to overcome the 'up to three nested loops' limitation? Something like this: Paul asked how to step two parameters at once. Note: To download the simulation files provided in this article, the reader must have LTSpice installed. Enter {R2} for the Resistance[]. So far, we saw how to apply variable parameters to find current and voltages for components that can have multiple values, and use the .tran simulation command to check the answers in terms of time. The way to do this is with a single .STEP command. In this article, we will explain in detail the parametric analysis(.step) method in LTspice. Yes you can do that (assuming you don't need to dynamically change the voltage within a .tran run) by parameterising the sources and using the table () function to look up the desired values. For LTspice, use tables to define params. In this article, we will briefly introduce the types of analysis that can be performed with LTspice. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Lets build the circuit in LTSpice. But this wouldn't vary the parameters independently. You can set custom plot colors in the preferences. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? Now LT spice knows what you're talking about when you start writing your scripts. Its quite a . In the "op" command editor you can enter something like this: It steps Imax from 0.1 to 0.3 in steps of 0.1 and computes a resistor value R using parameter Imax, Uin, some assumed voltage drop 0.85.. of a diode. How can I use it? The best answers are voted up and rise to the top, Not the answer you're looking for? Lets start by creating a user-defined variable in LTSpice. LTspice can be downloaded for free from here. This is useful for associating a name with a value for the sake of clarity and parameterizing your circuits. Is there a single-word adjective for "having exceptionally strong moral principles"? In this article, it was placed near source V1. Difficulties with estimation of epsilon-delta limit proof, Follow Up: struct sockaddr storage initialization by network format-string. If you plot multiple signals LTSpice will then plot each trace in a different color but each step for this signal in the same color. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Prior to joining ADI, Gabino held various positions in marketing, engineering, operations, and education at Linear Technology, Texas Instruments, and California Polytechnic State University. I had the sense that LTSpice does not support this, but I wanted to bounce this off of some other people first. The way to do this is with a single .STEP command. I am not sure if my question was well understood (yes I did find other similar posts but no applicable answers). Can I have two (or more) different symbols for the same LTspice schematic? This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing. A .param statement can also be placed on a schematic as a SPICE Directive. Interested in the latest news and articles about ADI products, design tools, training and events? The .param directive allows the creation of user-defined variables. #ltspiceIn this video I look at how sets of parameters can be stepped at the same time using the .step command together with the table function. Then use that parameter's values to control the other. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Thanks Ian.M, i tried it but cant seem to get it to work. For additional information you may view the cookie details. (I'm using the .op command). Finally to find the answer to b), lets have both circuits side to side with RL = 8, LTspice: Using the .STEP Command to Perform Repeated Analysis. Here we are simulating RL from 10 to 10k in steps of 100. I hope I'm being clear. Are you sure you wish to delete this message from the message archives of LTspice@groups.io? I've created a .asc file with basically two resistors in it offering 3 terminals and with their values defined as R* (Val/100) and R* (1-Val/100) based on parameter Val . If you want to lay out the schematic editor and graph pane, see the following article, Display the schematic editor and waveform graph side by side. To learn more, see our tips on writing great answers. I could open up the plot legend that shows the color of each point, but I don't see anywhere to change these settings. This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing. Does the LT Spice monte carlo simulation definitely output the max and min voltage for any number of simulation runs? LTSpice doesn't know what your talking about until you do that bit. Step a parameter run number, and from it generate the other parameter values required : Code: [Select] .step param run 1 3 1 ; middle no. Thanks for contributing an answer to Electrical Engineering Stack Exchange! Subscribe today! Lets build the LTSpice circuit with the original RL value first. If you preorder a special airline meal (e.g. More than three nested parametric sweeps in LTspice, https://groups.io/g/LTspice/topic/50201465#60860, How Intuit democratizes AI development across teams through reusability. In addition, since the schematic was prepared here, if you want to start analysis immediately, download it by clicking the link below. Why does LTspice XOR gate have more than two inputs? In this post (. Read more about our privacy policy. parameter combination) was used for each simulation. rev2023.3.3.43278. If I don't use the index in the tables I get the same error as indicated in the first post, The working solution was found after reading This article details how to use LTspice's Waveform Viewer. The DC operating point, .op simulation doesnt output an answer with respect to time. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. In any LTspice simulation, varying a parameter in a device or model is just as important as plotting voltages or currents, as it allows you to compare performance and develop your circuit intuition. Note: For this approach to run without errors, make sure that the size of the list is equal to number of variable parameters. Subscribe today! The Thevenin resistance is equal to RL for maximum power, in this case Rth = 12. After simulation, when you move the cursor close to the schematic wiring, the cursor changes to voltage probe. C: Place capacitor. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. I'm confused, do you want to simulate 3 situations or more? You should see ".step param R2 100 400 100" at the bottom of the screen. This time, set the feedback resistor R2 of the op-amp. .step param B list 3 4. During homework exercises or labs, sometimes you need to analyze the circuits for different components values. I think this message isn't appropriate for our group. In this LTspice requires setting of the signal source when simulating. Use MathJax to format equations. LTSpice: How to start the step of a voltage source at a different time in the transient simulation than t=0s? Confirm that ".step" of the dot command is displayed as ".step param R2 100 400 100". I know I could just export a CSV file and plot them with Octave or Excel, but it would be so much more useful to do it directly on LTSpice. I'm trying to learn about varying device parameters in LTSpice by setting up a potentiometer model so I can vary the rotation percent and see factors change within the circuit. Found the answer in the group. To find the maximum power transferred to RL, we can declare RL as a variable resistor but this time we will run the DC Operating .op simulation to get an answer for a list of RL values. Learn more about Stack Overflow the company, and our products. Will Gnome 43 be included in the upgrades of 22.04 Jammy? Now, it is set to perform transient analysis for 10msec. Dot command can be created with Edit Text on the Schematic. Asking for help, clarification, or responding to other answers. LTSpice, command line execution does not generate .raw file CPaul962 on Jan 28, 2020 I have a schematic consisting of a network of resistors, MOSFETs and DC voltage sources which I would like to do DC simulations of. Since (apparently) LT will only allow me to sweep through one variable at a time, I sweep through X and then I try to access the table's values according to the value that X has taken in that step. #ltspiceIn this video I look at how sets of parameters can be stepped at the same time using the .step command together with the table function. In many practical situations, a circuit is designed to provide power to a load, and sometimes it is desirable to maximize the power delivered to that same load (normally called RL). He holds a Master of Science degree in electrical and computer engineering from University of California, Santa Barbara. For How to set up detailed transient analysis. The command ".step" performs parameters sweeps. communities including Stack Overflow, the largest, most trusted online community for developers learn, share their knowledge, and build their careers. 2. We are commenting the second Spice directive for now. Refer to the following article for the detailed setting method of the signal source. Dear Donghoon Park, Thank you for creating such a useful tool! Notice Uin could be used as {Uin} in a voltage source or similar and so on. LTSpice: Step multiple parameters simultanious Uwe Bonnes Aug 1, 2006 Search Forums New Posts U Uwe Bonnes Jan 1, 1970 0 Aug 1, 2006 #1 Is it possible to define the step function so that it influences multiple parameters at once? It is performed simultaneously with transient analysis, AC analysis, DC sweep analysis, etc. Enclose your variable names in curly braces, in this case {RL}, and then set the SPICE directive .param with the desired valued for your variable name. Visit Stack Exchange Tour Start here for quick overview the site Help Center Detailed answers. In this article, we would like to easily check the analysis results with the LTspice voltage probe. If you ever get stuck working with LTSpice, there is a pretty comprehensive set of resources available in the Help menu, including more examples regarding usage. Create an account to follow your favorite communities and start taking part in conversations. LTspice parametric sweep: how to force the simulator to continue with the next step? If you've got a resistor R5 on your LTSpice schematic, for example, then Control-Right click over the component to pull up the Component Attributes dialogue box. rev2023.3.3.43278. Thanks for weighing in! Click Run on the toolbar to run the simulation. This works the same way for all kinds of components and with an external script to create .asc files it can be used as a crutch for LTspices missing monte carlo functonality. If you simulate multiple parameters at the same time, LTSpice will compute all possible combinations between those parameters. In this article, we will explain in detail the parametric analysis(.step) method in LTspice. I think this message isn't appropriate for our group. Click on "Simulate" icon bar then "Edit Simulation Cmd" to show the Transient section. Unfortunately, there's no editing messages but I knew whoever responded would be sure to correct me : ). 2: R1 = 1 M\$\Omega\$, R2 = 10 M\$\Omega\$, Sim. Then use that parameter's values to control the other. However, with the .step increase order method that can be done faster. Yes I realized that immediately after sending. LTSpice: Step multiple parameters simultanious Uwe Bonnes Aug 1, 2006 Aug 1, 2006 #1 U Uwe Bonnes Guest Is it possible to define the step function so that it influences multiple parameters at once? In this article, we only used the waveform viewer to check the voltage waveforms of V(OUTPUT) with the voltage probe. I've called the parameter Rx: The 1st line defines the steps I want to take as detailed above. Then you use .include and .step param and the TABLE function in LTspice to perform the sweeps. Here is a list of some hotkeys for creating your schematic: R: Place resistor. The best answers are voted up and rise to the top, Not the answer you're looking for? https://groups.io/g/LTspice/topic/50201465#60860). Making statements based on opinion; back them up with references or personal experience. to get control about its order of execution." So as long it is in the same text box, it will follow the order you write it in. Press question mark to learn the rest of the keyboard shortcuts. For the types of analysis, please see the following article. If you just want to simulate the 3 scenarios I wouldn't bother doing it with spice. However, to my knowledge it is not possible to achieve what you asked for. L: Place inductor. What I mean to do exactly is this: If there were just one resistor whose resistance to vary, then I would just set its resistance to "{r1}" (I use lower case letters to make it a different variable/parameter than R1) and use a command such as: However, since I have to change two parameters (together) two times each, I have read here that (at least on LTSpiceIV) that a workaround to my problem could be using something like this: Upon doing the simulation, I get the following warnings: For some reason, the simulation doesnt "break" if I add one extra element to the table. What is \newluafunction? Import Parametric Sweep data from LTSPice into Matlab, Modelling a low-pass filter on LTSpice to filter an input square wave at 50kHz to obtain a sinusoidal output at 50Hz, LTSpice, AD8677 instance has more connection terminals than the definition, LTspice singular matrix error by changing model parameters.