Add a .step command via a SPICE directive that specifies the steps for the parameter by a linear, logarithmic or list of values. There are two ways to examine a circuit in LTspice by changing the value for a particular parameter: you can either manually enter each value and then simulate the circuit to view the response, or use the .step command to sweep across a range of values in a single simulation run. The new topic will begin with this message. Then use that parameter's values to control the other. 2022-06-30; I think this message isn't appropriate for our group. 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 Learn more about Stack Overflow the company, and our products. flower arranging classes northern virginia. How to use .step param with more than two parameters in LTSpiceIV, electronics.stackexchange.com/questions/20811/, How Intuit democratizes AI development across teams through reusability. Interested in the latest news and articles about ADI products, design tools, training and events? Its quite a simple implementation that can be used to go trough multiple parameters at the same time.LTspice Tutorial series:EP1-Getting started: https://youtu.be/JRcyHuyb1V0EP2-AC simulation and the Baxandall tone control circuit: https://youtu.be/P_ENvucaZkIEP3-.param and .step directives: https://youtu.be/ARE5nwiHI0QEP4-How to import libraries and component models: https://youtu.be/8V5XabccFaEEp5- Stock example simulations to play with: https://youtu.be/MwfeMjcM4zYEp6- Basics of FFT analysis and .four statment: https://youtu.be/rVAvW1Jh2AEEP7- Dependent voltage and current sourceshttps://youtu.be/Jn8mJG3qeooEp8- Turning a datasheet into a component modelhttps://youtu.be/0smuo8bMRn4EP9- Independent voltage and current sourceshttps://youtu.be/nPZ7vneN3v8Ep10- .wave statement and audio file processinghttps://youtu.be/mdJm-TzrBsAEp11 The effect of temperature on your circuithttps://youtu.be/VzxnNrOMcMoEP12 Modeling a DC brushed motorhttps://youtu.be/Wc4XzTrWSpoEp13- Worst Case, Monte Carlo and Gaussian statistics circuit analysishttps://youtu.be/NdGqboW2VcYEP14 - Digital circuits and logic gates https://youtu.be/JttE2NObDPMEP15- SMPS EMI and electrical noise and filtershttps://youtu.be/QEAzcaiBrpYEP16- Feedback loop simulationhttps://youtu.be/X4yaBwaO1gkEp17 - Verifying Simulation Modelshttps://youtu.be/DSDiIkKQaAEEp18 - Simulating Capacitorshttps://youtu.be/QpWPTolhfEoEp 19 - Simulating Inductorshttps://youtu.be/65fNDRows90EP 20 - Noise simulations https://youtu.be/Dh5XmFXlljIEp21 - Models and Librarieshttps://youtu.be/GUFMfSlD2AMEp22- Voltage and current limited sourcehttps://youtu.be/DnKnuJd3-ecEp23- Measuring Power Factorhttps://youtu.be/qZXOMPxbqh8Ep24 - Modeling a vacuum tube triodehttps://youtu.be/7v9dG1uteAQEp25- Using standard symbolshttps://youtu.be/BFMVujjH0loEp26- Modeling transformershttps://youtu.be/muUwe8X51oYEp27 - Stepping sets of parametershttps://youtu.be/1iOzX91LJ8gSpecial Thanks to all my supporters on Patreon! The only change that we need to make is to add a set of values for the variable parameter RL. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. You need to replace this with your parameter designator; put that inside {} brackets, e.g. Now LT spice knows what you're talking about when you start writing your scripts. Especially @afiskon and Ralf B.!If you liked this video be sure to check out my other videos and you can also subscribe to be up to date with all the new ones!If you want to support the creation of more and better videos please consider checking out: https://www.patreon.com/feszelectronics Perform parametric analysis using the schematic in the following article. Doesn't analytically integrate sensibly let alone correctly. Lastly the .op command drives the operation. We are commenting the second Spice directive for now. This is useful for associating a name with a value for the sake of clarity and parameterizing your circuits. Dear Donghoon Park, Thank you for creating such a useful tool! E.G: In this example, I want to modify two resistors (R5 and R6) so I can see the output of my regulators, assuming that I change the values from 1 ohm to 5000 ohms over 100 steps. We are going to work on this exercise in a slightly different order than the one asked by the exercise. Dot command can be created with Edit Text on the Schematic. Lets use the circuit below as our first example: Lets say we want to analyze the output voltage (Vo) for several different values of a load resistor (RL). This could be a case of you get what you pay for. run a simulation immediately. Why is this sentence from The Great Gatsby grammatical? By clicking Accept All, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. I've called the parameter Rx: The 1st line defines the steps I want to take as detailed above. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Input Name of parameter to sweep: R2, Nature of sweep: Linear, Start value: 100, Stop value: 400, Increment: 100. If you check the voltage waveform of OUTPUT, you can see that it increases from 2V to 8V each time the parameter of feedback resistor of op amp increases. So I wrote a C++ script to create the tables as (long) text files. Refer to the following article for the detailed setting method of the signal source. If you just want to simulate the 3 scenarios I wouldn't bother doing it with spice. Lets start by creating a user-defined variable in LTSpice. did phineas and ferb die in a car accident. After we finish updating our website, you will be able to set your cookie preferences. As .tran 10m of dot command appear, place it at an appropriate position. 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. . Create an account to follow your favorite communities and start taking part in conversations. 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? This is useful for associating a name with a value for the sake of clarity and parameterizing sub circuits so . The LTSPICE function u(x) is a step function with u(x)=1 for x > 0 and u(x)=0 else. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Parametric analysis is performed simultaneously with transient analysis, AC analysis, DC sweep analysis and so on. Click on "Simulate" icon bar then "Edit Simulation Cmd" to show the Transient section. Note: To download the simulation files provided in this article, the reader must have LTSpice installed. 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 this exercise, we have 2 variable parameters, Vs and R, which gives a total of 4 possible solutions. 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. Then use that parameter's values to control the other. http://tech.groups.yahoo.com/group/LTspice/files/%20Tut/Stepping%20to%20the%20max/. 1995 - 2023 Analog Devices, Inc. All Rights Reserved, LT6108 / LTC6994 Demo Circuit - Energy-Tripped Circuit Breaker with Automatic Delayed Retry (5-80V Input, 500mA Threshold), LTspice: AC Analysis Using The Step Command, LTspice: Using the .STEP Command to Perform Repeated Analysis. You can combine your sweeps by inventing integers that composite them together and then divide them back out using LTspice functions that are available to you. After running the simulation, you can iterate through all the answers the same way as we did in Figure 6 and 7. The way to do this is with a single .STEP command. We are going to find c) and d) first and then find the equivalent Thevenin a), and at last we will find the current in RL for b). Disconnect between goals and daily tasksIs it me, or the industry? A place to ask questions, discuss topics and share projects related to Electrical Engineering. Groups.io. I think this message isn't appropriate for our group. The simulation time varies depending on the size of the circuit. Prior to joining ADI, Gabino held various positions in marketing, engineering, operations, and education at Linear Technology, Texas Instruments, and California Polytechnic State University. This video provides an overview of how to use the .STEP command to perform repeated analysis of a circuit in LTspice. {R5} then Save. The Group moderators are responsible for maintaining their community and can address these issues. For example, combine parameter A and parameter B into a new parameter, (A*100+B), and sweep that. (I.e. If you simulate multiple parameters at the same time, LTSpice will compute all possible combinations between those parameters. LTSpice doesn't know what your talking about until you do that bit. #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. Figure 1. Is there a single-word adjective for "having exceptionally strong moral principles"? I could open up the plot legend that shows the color of each point, but I don't see anywhere to change these settings. The way to do this is with a single .STEP command. Stepping Parameters in LTspice IV LinearTechnology 10.8K subscribers Subscribe 486 Share Save 103K views 11 years ago LTspice with with Gabino Alonso, Strategic Marketing. Read more about our privacy policy. He holds a Master of Science degree in electrical and computer engineering from University of California, Santa Barbara. Therefore, for: .step param A list 1 2. If you want to lay out the schematic editor and graph pane, see the following . Difficulties with estimation of epsilon-delta limit proof, Follow Up: struct sockaddr storage initialization by network format-string. Does the LT Spice monte carlo simulation definitely output the max and min voltage for any number of simulation runs? When a temperature sweep is used, LTSpice automatically vary the properties of components with respect to desired temperatures. After much thrashing around, I found there are two aspects to this problem that need to be explored. By computing 1-u(Temp) the temperature coefficient tc3 is effective only if Temp < 0 C. You can set custom plot colors in the preferences. Open the edit screen of resistance R2 by "right clicking" the resistance R2 of the schematic with the mouse. For additional information you may view the cookie details. So the table of the values start with the index identifier (here n) then follows the pairs index, value . and what would happen then? Another use of variable parameters can be to find the maximum power transferred to a load. I guess I'll just have to export the data and plot it elsewhere. .step param B list 3 4. After we finish updating our website, you will be able to set your cookie preferences. Setup the transient command as below. Visitors have the right to withdraw their consent. (c) and (d) answer -> RL = 12 for P = 33.33 W. To answer (a), we need the open circuit voltage (Voc) and the Thevenin resistance (Rth). The DC operating point, .op simulation doesnt output an answer with respect to time. LTspice can use auxiliary units other than m as shown in the following table. It could be {Pickle1} and it would still work. You are missing a comma in the Vac table after the pair 3,200V. Add a cursor to the graph and check the value of RL that gives you the maximum power value (the global maximum of the power curve). How should I go about getting parts for this bike? Trying to understand how to get this basic Fourier Series. For How to set up detailed transient analysis. I'm confused, do you want to simulate 3 situations or more? Press J to jump to the feed. In this article, we will briefly introduce the types of analysis that can be performed with LTspice. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Make sure the "SPICE directive" is selected and enter ".step". color of data point should only depend on one parameter, not the other.). Asking for help, clarification, or responding to other answers. In this article, it was placed near source V1. 2: R1 = 1 M\$\Omega\$, R2 = 10 M\$\Omega\$, Sim. Multiple; T: tera: 10 12: G: giga: 10 9: Meg: mega: 10 6: k: kilo: 10 3: m: milli: 10-3: u: micro: 10-6: n: nano: 10-9: p: pico: 10-12: f: femto: 10-15: . You can combine your sweeps by inventing integers that composite them together and then divide them back out using LTspice functions that are available to you.