The result would be three simulation runs with C1 matching each of the values specified in the ".step" statement for each run. So I wrote a C++ script to create the tables as (long) text files. Make sure that the parameter of R2 is {R2}. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? ltspice step multiple parameters. Would the magnetic fields of double-planets clash? Are you sure you wish to delete this message from the message archives of LTspice@groups.io? 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. Here is a list of some hotkeys for creating your schematic: R: Place resistor. Is there a single-word adjective for "having exceptionally strong moral principles"? You should see ".step param R2 100 400 100" at the bottom of the screen. After placement, right-click ".step" of the mouse to open the ".step Statement Editor" screen. did phineas and ferb die in a car accident. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The best answers are voted up and rise to the top, Not the answer you're looking for? 2. Input Name of parameter to sweep: R2, Nature of sweep: Linear, Start value: 100, Stop value: 400, Increment: 100. Subscribe today! 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. The specialty shows in the expression 1-u(Temp) in the last line. After simulation, the graph pane will appear at the top of the schematic with the default settings of LTspice. Thankfully, LTSpice generates data when doing a transient analysis with multiple stepping parameters fairly easily. 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. Instead a combination of parameters using SPICE directives needs to be called for help . It described a complete circuit, so I extracted just the SCR description. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup, More than three nested parametric sweeps in LTspice. I managed to do it using the TABLE function for each of the five variables. We are commenting the second Spice directive for now. You can set custom plot colors in the preferences. Why does it seem like I am losing IP addresses after subnetting with the subnet mask of 255.255.255.192/26? Remember that R5 relates to the parameter designator. End result is that my circuit, which other than those two values is in a fixed state, is now complete and, in the example I was trying to get to, I can see the effect on the regulated output. You can break that back out into A and B as it executes. To plot a specific answer, right click on the graph, go to View and select Select Steps. You should now see .tran 10m at the bottom of the screen. Visitors have the right to withdraw their consent. Your control variable you are stepping could be a phase angle or time delay or similar that you input in one or more formulas/expressions to obtain resulting component values or parameters to be applied in the design as {parameter} However, with the .step increase order method that can be done faster. Model Statements: Some devices, such as, transistors and diodes require information on the device in order to make calculations. The command .step performs parameters sweeps. 2023 Please refer to the linked article for an explanation of After all, in order to learn how to use LTspice, it should be faster to use the practice form and to learn first than to read the instruction manual. Why does LTspice XOR gate have more than two inputs? The only change that we need to make is to add a set of values for the variable parameter RL. Use MathJax to format equations. Any number of parameters can be made into variables, however LTspice will run simulations on all the different combinations of each value. .step param B list 3 4. You need to replace this with your parameter designator; put that inside {} brackets, e.g. Now you can start using the Spice Directive dialogue box (.op Icon top right) and enter your script. Visit Stack Exchange Tour Start here for quick overview the site Help Center Detailed answers. This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing. Click Run on the toolbar to run the simulation. The proper directive for your case would then be: and set the value of the resistors to {R1} and {R2} respectively. LTSpice for Windows introductory tutorial The circuit It was used in class, and it is a nice example of a circuit that can be handled using node-voltage, mesh-current, or superposition techniques. Press keyboard letter "T" to show the spice directive. Welcome to EE.SE! How to pass parameters to subcircuits in LTSpice with the include statement? parameterized capacitance in the R-C circuit I had the sense that LTSpice does not support this, but I wanted to bounce this off of some other people first. Create an account to follow your favorite communities and start taking part in conversations. What is the point of Thrower's Bandolier? Menu Asking for help, clarification, or responding to other answers. 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. I'm just wondering if I can manually change the color settings of the data points. Difficulties with estimation of epsilon-delta limit proof, Follow Up: struct sockaddr storage initialization by network format-string. 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. The .step command in this case steps the parameter R through the values 10k, 20k and 30k. Subject of the new topic: Thanks Ian.M, i tried it but cant seem to get it to work. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? The list examples detailed above is a different way of achieving the end result required, but it looks like some of the comments are because, as was the case with me, it was not understood that you can't use the component designators without doing the {} thing. of runs 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. 1995 - 2023 Analog Devices, Inc. All Rights Reserved, LTspice: Using the .STEP Command to Perform Repeated Analysis. 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. This time, set the feedback resistor R2 of the op-amp. Thank you. 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. He holds a Master of Science degree in electrical and computer engineering from University of California, Santa Barbara. Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? How? For example, we can parameterize the capacitance C1 in this simulation with the following modifications to the schematic. The best answers are voted up and rise to the top, Not the answer you're looking for? To be clear I've used {R5} for my convenience and understanding. and what would happen then? 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. The DC operating point, .op simulation doesnt output an answer with respect to time. Thanks for weighing in! Press question mark to learn the rest of the keyboard shortcuts. The .param directive allows the creation of user-defined variables. In this post (. I have an LCR circuit including voltage sources where I need to sweep more than three parameters (nested sweep) for a transient simulation. In this article, it was placed near source V1. I hope I'm being clear. You can duplicate this by taking the text at the end of this section and saving it as a file in your LTSpice Relation between transaction data and transaction id. Step independent voltage source V1 from 1 to 20 logarithmically with 5 points per octave. Then use that parameter's values to control the other. As .tran 10m of dot command appear, place it at an appropriate position. Linear regulator thermal information missing in datasheet. 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). In this case, the resistance value is varied from 1k to 10k. Learn more about Stack Overflow the company, and our products. One parameter sweep/step can control multiple component values through expressions. .param Rf=table(n,1,1.3k,2,1.1k,3,1.2k,4,1k), .param Cf=table(n,1,54p,1,64p,2,64pF,4,64pF), So Rf gets the value of the current index ( defined in the .step directive) parameter combination) was used for each simulation. On the output graph, add the signals of interest to that graph (in this case Vo) and add a cursor. There are two ways to examine a circuit by changing the value of a parameter: You can either manually enter each value then re-simulate the circuit, or you can use the .STEP command to sweep across a range of values in a single simulation run and produce a side-by-side comparison. After running the simulation we get the following plot with Vo vs RL. into the resistor value field. Why is this sentence from The Great Gatsby grammatical? For additional information you may view the cookie details. http://tech.groups.yahoo.com/group/LTspice/files/%20Tut/Stepping%20to%20the%20max/. MathJax reference. I've done the trick with the Component Attributes dialogue on both components already. Analog Devices is in the process of updating our website. LTspice is employed for this experiment. D: Place diode. For more information on how to use the waveform viewer, see the following articles: The schematic used for the parametric analysis can be downloaded from the link below. 'Jonk' may be up to something but still unclear how to perform for example 5x10x4x4x6=4800 independent simulations by 'combining' parameters and then 'breaking them back'. Interested in the latest news and articles about ADI products, design tools, training and events? The way to do this is with a single .STEP command. The command ".step" performs parameters sweeps. #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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. It is provided free of charge by Analog Devices (originally by Linear Technology). Does a summoned creature play immediately after being summoned by a ready action? As regards your second question, X would be the different indexes that let me access the table's values. For example, combine parameter A and parameter B into a new parameter, (A*100+B), and sweep that. Click Simulate-Edit Simulation Cmd in the menu bar to open the Edit Simulation Command screen. Gabino Alonso is currently the director of strategic marketing for the Power by Linear Group. First, prepare a schematic for parametric analysis with LTspice. If you just want to simulate the 3 scenarios I wouldn't bother doing it with spice. 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. It is performed simultaneously with transient analysis, AC analysis, DC sweep analysis, etc. I am not sure if my question was well understood (yes I did find other similar posts but no applicable answers). Dear Donghoon Park, Thank you for creating such a useful tool! Lets find the value of RL that corresponds to the the maximum power transfer to RL in the circuit from Figure 4. Now lets add a second trace on the graph and add the following SPICE expression, V(vo)*I(R3), to calculate the power across R3 = RL. But this wouldn't vary the parameters independently. 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. Parametric analysis analyzes while changing parameters such as resistance, capacitor, inductor, and power supply of electronic circuit. Enter {R2} for the Resistance[]. rev2023.3.3.43278. I think this violates the Terms of Service. Another way to simulate a set of values at the same time is to use the increasing order option of the .step command. To learn more, see our tips on writing great answers. 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. 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. Refer to the following article for the detailed setting method of transient analysis. At LTspice, are there any methods to change the values at once? By computing 1-u(Temp) the temperature coefficient tc3 is effective only if Temp < 0 C. 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. 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. LTspice - Resistor value controlled by on/off switch, How can one label a node with more than one name in SPICE/ LTspice. In this article, we will explain in detail how to set the simulation command used for the following six types of analysis. LTspice table function. Parametric analysis is performed simultaneously with transient analysis, AC analysis, DC sweep analysis and so on. Can I specify that it should only change color when stepping one of the parameters? Notice Uin could be used as {Uin} in a voltage source or similar and so on. To know which value of RL corresponds to that particular answer, right click with your mouse on top of it and a pop up window will show you the respective parameter value. Making statements based on opinion; back them up with references or personal experience. The way to do this is with a single .STEP command. Use MathJax to format equations. 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. rev2023.3.3.43278. To understand the LTspice Model Parameters of Components we shall first understand the .param directive used in LTspice simulation software. A place to ask questions, discuss topics and share projects related to Electrical Engineering. #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. I would like to simulate those three situations and plot them together. From the list of options select the desired one. Lastly the .op command drives the operation. AC Op-amp integrator with DC Gain Control in LTspice, How to handle a hobby that makes income in US. Another use of variable parameters can be to find the maximum power transferred to a load. vegan) just to try it, does this inconvenience the caterers and staff? The problem was that the size of the tables (given by the number of total parameter combinations) was prohibitive to write by hand. You can break that back out into A and B as it executes. Unfortunately, there's no editing messages but I knew whoever responded would be sure to correct me : ). LTspice can be downloaded for free from here. Lets start by creating a user-defined variable in LTSpice. Are you sure you wish to repost this message? run a simulation immediately. C: Place capacitor. So the table of the values start with the index identifier (here n) then follows the pairs index, value . You can change them manually, which will take some time, but you can also set a variable parameter for RL and change its value automatically. In this article, we will briefly introduce the types of analysis that can be performed with LTspice. Found the answer in the group. Something like this: Paul asked how to step two parameters at once. https://groups.io/g/LTspice/topic/50201465#60860). and what would happen then? I need to do three transient simulations with different values of certain resistors (conveniently called R1 and R2) in each. Would the magnetic fields of double-planets clash? I need to try a large number of different combinations of parameter values (I have 5 parameters, each of them can take anywhere from 3 to 10 values, for a total number of combinations up to 5000). I cannot use Monte Carlo since the cursor information is missing (i.e. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. Of course, it does not matter if you enter 0.01 instead of 10m without using auxiliary units. Analog Devices is in the process of updating our website. LTspice can use auxiliary units other than m as shown in the following table. Making statements based on opinion; back them up with references or personal experience. In this article, we will focus on how to set up a independent voltage source for analysis. Are you sure you wish to repost this message? Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. - jonk Apr 16, 2020 at 4:28 The probe cursor indicates which 'key' (i.e. It only takes a minute to sign up. http://ltwiki.org/?title=Undocumented_LTspice#Stepping_a_Model, Powered by SMFPacks Advanced Attachments Uploader Mod. The addition of the curly braces around the variable is important as it tells LTspice IV that X is a parameter. Firstly, The parameter you wish to vary needs to be designated. Why does LTspice XOR gate have more than two inputs? communities including Stack Overflow, the largest, most trusted online community for developers learn, share their knowledge, and build their careers. I think this message isn't appropriate for our group. Radial axis transformation in polar kernel density estimate. Figure 1. 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 What is \newluafunction? This is useful for associating a name with a value for the sake of clarity and parameterizing your circuits. How should I go about getting parts for this bike? 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). Make sure the "SPICE directive" is selected and enter ".step". You are missing a comma in the Vac table after the pair 3,200V. Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? Check that SINE is selected and DC offset [V]: 0, Amplitude [V]: 2, Freq [Hz]: 500 is input. Therefore, for: .step param A list 1 2. communities including Stack Overflow, the largest, most trusted online community for developers learn, share their knowledge, and build their careers. For this exercise, we have 2 variable parameters, Vs and R, which gives a total of 4 possible solutions. One parameter sweep/step can control multiple component values through expressions. After running the simulation, you can iterate through all the answers the same way as we did in Figure 6 and 7. Besides, the Monte Carlo will take too long and it may 'duplicate' some combinations. is no. Here we are simulating RL from 10 to 10k in steps of 100. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. For this exercise, we have 2 variable parameters, Vs and R, which gives a total of 4 possible solutions. For instance, the forward voltage of a diode will change over different temperatures, the VBE of transistors, the RDSon of MOSFET and so on. In this article, we would like to easily check the analysis results with the LTspice voltage probe. Then you use .include and .step param and the TABLE function in LTspice to perform the sweeps. Interested in the latest news and articles about ADI products, design tools, training and events? Connect and share knowledge within a single location that is structured and easy to search. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup, How to use .step param with more than two parameters in LTSpiceIV. I understand this would be easy to do if the parameters were somehow related (eg: set the value of C={R*constant} or whatever), but what if Confirm that ".step" of the dot command is displayed as ".step param R2 100 400 100". "You can make nested .step loops up to 3 levels. Of course, if you know the syntax format, you can also enter it on the "Edit Text on the Schematic" screen. Thanks for contributing an answer to Electrical Engineering Stack Exchange! After much thrashing around, I found there are two aspects to this problem that need to be explored. Perform parametric analysis using the schematic in the following article. PSPICE is more suited for this but if you are good at scripting, this should be possible to solve in NGSPICE. What LTSpice does is automatically set each step to have a certain color automatically. 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. this is how I roll it in 1 run (same method as what mr stilltrying said). The Thevenin resistance is equal to RL for maximum power, in this case Rth = 12. Open the edit screen of resistance R2 by "right clicking" the resistance R2 of the schematic with the mouse. This article details how to use LTspice's Waveform Viewer. Setup the transient command as below. This multiple value parameter might have values with single quote, such as: abc, efg's, sms dio, 'you's dfd. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I would for example like to increase some capacitor and decrease the stimulus volrtage source simultaniously. LTSpice: How to start the step of a voltage source at a different time in the transient simulation than t=0s? 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. Google searching for SCR SPICE models, I found a SPICE file on EDN's website. LTspice: How can I show multiple probes with waveforms using stepping parameters in different colors? It only takes a minute to sign up. 2: R1 = 1 M\$\Omega\$, R2 = 10 M\$\Omega\$, Sim. Read more about our privacy policy. However, to my knowledge it is not possible to achieve what you asked for. Any SPICE directive with a * in front of it, will not run during simulation. Visit Stack Exchange Tour Start here for quick overview the site Help Center Detailed answers. Your answer is a simple tutorial on a basic LTspice concept. Are you sure you wish to delete this message from the message archives of LTspice@groups.io? Trying to understand how to get this basic Fourier Series. Its quite a . The general idea (not the implementation) came from the LTspice yahoo group (e.g. How to use Slater Type Orbitals as a basis functions in matrix method correctly? 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. In LTspice parameters are variables that can be reused throughout the schematic. Dot command can be created with Edit Text on the Schematic. Note: To download the simulation files provided in this article, the reader must have LTSpice installed. Each param should have 3 pairs in it, not three values. The .step command has different flavors. In this article, we will explain in detail the parametric analysis(.step) method in LTspice. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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! One way to achieve this is to create a list of desired values to test. They are defined with the .op SPICE directive " .param <name> = <value> ". After simulation, when you move the cursor close to the schematic wiring, the cursor changes to voltage probe. Normally, LTspice sets the resistance element parameter to a constant such as R = 10. Define the component parameter with a variable by editing the component attribute (Ctrlright-click on the component) and entering {X} for the Value, where X is a user defined variable name. (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).