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? 1. This time, set the feedback resistor R2 of the op-amp. "You can make nested .step loops up to 3 levels. Subscribe today! The best answers are voted up and rise to the top, Not the answer you're looking for? Why does LTspice XOR gate have more than two inputs? It would take time to add and adjust values using the .step list method. 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. 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). 2023 As regards your second question, X would be the different indexes that let me access the table's values. Here is an example waveform response of an RC circuit, for which the capacitance is stepped through three values. Doesn't analytically integrate sensibly let alone correctly. To learn more, see our tips on writing great answers. 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 I think this message isn't appropriate for our group. Welcome to EE.SE! What is \newluafunction? Does a summoned creature play immediately after being summoned by a ready action? 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. After we finish updating our website, you will be able to set your cookie preferences. Lets start by creating a user-defined variable in LTSpice. One parameter sweep/step can control multiple component values through expressions. In addition, since the schematic was prepared here, if you want to start analysis immediately, download it by clicking the link below. What sort of strategies would a medieval military use against a fantasy giant? 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. Visit Stack Exchange Tour Start here for quick overview the site Help Center Detailed answers. The command ".step" performs parameters sweeps. A .param statement can also be placed on a schematic as a SPICE Directive. If I'd used {Pickle} then the line would read: The next two lines in the script above tell LTSpice that the parameters for R5 and R6 should follow the steps designated as Rx. Model Statements: Some devices, such as, transistors and diodes require information on the device in order to make calculations. rev2023.3.3.43278. I think this violates the Terms of Service. Another use of variable parameters can be to find the maximum power transferred to a load. As .tran 10m of dot command appear, place it at an appropriate position. A .model statement tells LTspice what parameters to use for modeling semiconductors. In this article, it was placed near source V1. and what would happen then? Thanks for contributing an answer to Electrical Engineering Stack Exchange! Your answer is a simple tutorial on a basic LTspice concept. MathJax reference. Lets find the value of RL that corresponds to the the maximum power transfer to RL in the circuit from Figure 4. The probe cursor indicates which 'key' (i.e. Is it possible to step 2 parameters together? This video provides an overview of how to use the .STEP command to perform repeated analysis of a circuit in LTspice. 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. run a simulation immediately. Any number of parameters can be made into variables, however LTspice will run simulations on all the different combinations of each value. 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. 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. It is important to understand that if you place the ground reference in a different point you are going to get different results. What LTSpice does is automatically set each step to have a certain color automatically. I need to do three transient simulations with different values of certain resistors (conveniently called R1 and R2) in each. Then, in the waveform viewer, you can have three plot panes each showing only the result for each step by specifying "@" for the displayed value. In this article, we will briefly introduce the types of analysis that can be performed with LTspice. Note: For this approach to run without errors, make sure that the size of the list is equal to number of variable parameters. Menu 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. During homework exercises or labs, sometimes you need to analyze the circuits for different components values. Make sure the "SPICE directive" is selected and enter ".step". LTspice IV: Using the .STEP Command to Perform Repeated Analysis. 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). Once the simulation stops, I need to use cursors in Probe to figure out which combination of parameters generates close to a a certain result. After placement, right-click ".step" of the mouse to open the ".step Statement Editor" screen. You can break that back out into A and B as it executes. The Thevenin resistance is equal to RL for maximum power, in this case Rth = 12. Well for one the table command wants an index, which is X, then a set of xy pairs. If you move the keys up and down in your keyboard you will be able to change between all the different answers. 1995 - 2023 Analog Devices, Inc. All Rights Reserved, LTspice: Using the .STEP Command to Perform Repeated Analysis. Using Kolmogorov complexity to measure difficulty of problems? The waveform viewer is a function that displays the simulation results executed with LTspice as a LTspice-Independent Voltage Source Setting. For additional information you may view the cookie details. LTspice parametric sweep: how to force the simulator to continue with the next step? 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. Trying to understand how to get this basic Fourier Series. You've likely already given it a value, eg 1k0. If you preorder a special airline meal (e.g. Lets build the circuit in LTSpice. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Subject of the new topic: I cannot use Monte Carlo since the cursor information is missing (i.e. Press keyboard letter "T" to show the spice directive. Here we are simulating RL from 10 to 10k in steps of 100. color of data point should only depend on one parameter, not the other.). .step param B list 3 4. Read more about our privacy policy. I think this message isn't appropriate for our group. 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. I am not sure if my question was well understood (yes I did find other similar posts but no applicable answers). rev2023.3.3.43278. To see the results with respect to time, we need to change the simulation type to .tran, transient analysis. It described a complete circuit, so I extracted just the SCR description. The LTSPICE function u(x) is a step function with u(x)=1 for x > 0 and u(x)=0 else. 2023 For multiple lines in the "op" editor window use CTRL+M to keep all params in same textbox. Another way to simulate a set of values at the same time is to use the increasing order option of the .step command. communities including Stack Overflow, the largest, most trusted online community for developers learn, share their knowledge, and build their careers. 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. ltspice step multiple parameters. Thanks for contributing an answer to Electrical Engineering Stack Exchange! If you just want to simulate the 3 scenarios I wouldn't bother doing it with spice. Make sure that the parameter of R2 is {R2}. Now LT spice knows what you're talking about when you start writing your scripts. posted on January 25, 2022. Then you use .include and .step param and the TABLE function in LTspice to perform the sweeps. C: Place capacitor. Add a .step command via a SPICE directive that specifies the steps for the parameter by a linear, logarithmic or list of values. How to pass parameters to subcircuits in LTSpice with the include statement? D: Place diode. Interested in the latest news and articles about ADI products, design tools, training and events? 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. I could open up the plot legend that shows the color of each point, but I don't see anywhere to change these settings. Like this: .params R=tbl (n, 1,1k, 2,10k, 3, 22k) .params C=tbl (n, 1,1p, 2,10p, 3,22p) use {C} as cap value and {R} as resistor value Then use step command .step param n list 1,2,3 Click to expand. 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. 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. 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. 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 .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) After much thrashing around, I found there are two aspects to this problem that need to be explored. 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? How to use Slater Type Orbitals as a basis functions in matrix method correctly? Hope that explanation helps someone else so they're not spending three hours trying to figure out why the code lifted from the examples here may not be working. LTspice can use auxiliary units other than m as shown in the following table. Use MathJax to format equations. Whats the grammar of "For those whose stories they are"? The Group moderators are responsible for maintaining their community and can address these issues. For example, we can parameterize the capacitance C1 in this simulation with the following modifications to the schematic. Something like If you want to have the values of a resistor near to it, you can also enter (instead of value, when right clicking onto it). 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. Radial axis transformation in polar kernel density estimate. For additional information you may view the cookie details. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I hope I'm being clear. Thanks Ian.M, i tried it but cant seem to get it to work. Analog Devices is in the process of updating our website. MathJax reference. What LTSpice does is automatically set each step to have a certain color automatically. This time I set the variable to R2, but anything with alphanumeric characters is fine. Now lets say that we want to analyze Vo for 10 different types of RL. They are defined with the .op SPICE directive " .param <name> = <value> ". 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. I think this violates the Terms of Service. To be clear I've used {R5} for my convenience and understanding. 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. I have tried setting X to 0 1 2 instead of 1 2 3, but that does not work either. Will Gnome 43 be included in the upgrades of 22.04 Jammy? The new topic will begin with this message. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. So the table of the values start with the index identifier (here n) then follows the pairs index, value . 2: R1 = 1 M\$\Omega\$, R2 = 10 M\$\Omega\$, Sim. Would the magnetic fields of double-planets clash? 2022-06-30; Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Is there a single-word adjective for "having exceptionally strong moral principles"? This article details how to use LTspice's Waveform Viewer. The .step command is then used to step R through different values. Open the edit screen of resistance R2 by "right clicking" the resistance R2 of the schematic with the mouse. On the output graph, add the signals of interest to that graph (in this case Vo) and add a cursor. {R5} then Save. In LTspice parameters are variables that can be reused throughout the schematic. Now you can start using the Spice Directive dialogue box (.op Icon top right) and enter your script. PSPICE is more suited for this but if you are good at scripting, this should be possible to solve in NGSPICE. 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. 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. You should see ".step param R2 100 400 100" at the bottom of the screen. The way to do this is with a single .STEP command. 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). It only takes a minute to sign up. Step-by-step explanation lStep 1: Plot for step 6-7 Step 2: Plot for step 7-8 Step 3: Plot for step 9 Step 4: Plot for step 10 Step 5: Plot for step 11 Step 6: Plots for step 12 Step 7: Plot for step 13 Step 8: Plot for step 14 Crossing point: Frequency=336.5 Hz, Magnitude =695.218mV, Phase =44.09 o 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. Dot command can be created with Edit Text on the Schematic. The new topic will begin with this message. Remember that R5 relates to the parameter designator. Note: * is used as a comment in SPICE. Why does LTspice XOR gate have more than two inputs? Visitors have the right to withdraw their consent. LTSpice doesn't know what your talking about until you do that bit. 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. 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. To plot a specific answer, right click on the graph, go to View and select Select Steps. From the list of options select the desired one. One way to achieve this is to create a list of desired values to test. 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. 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. 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. For this exercise, we have 2 variable parameters, Vs and R, which gives a total of 4 possible solutions. 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 the parametric analysis(.step) method in LTspice. Then use that parameter's values to control the other. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? 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 The command .step performs parameters sweeps. Select Transient and enter 10 m for Stop time. 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. #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. But this wouldn't vary the parameters independently. Subject of the new topic: Andy More All Messages By This Member Andy I #129250 Example:.step param x list 0 1 2 3 4 5.param y={x}or.param y=table(x,+ 0, 5,+ 1, 7,+ 2, 18,+ 3, 22,+ 4, -6,+ 5, 5)or whatever. You are missing a comma in the Vac table after the pair 3,200V. Click Run on the toolbar to run the simulation. How? To implement this in LTspice, perform the following steps: Figure 1. Steps may be linear, logarithmic, or specified as a list of values. After running the simulation, you can iterate through all the answers the same way as we did in Figure 6 and 7. I would for example like to increase some capacitor and decrease the stimulus volrtage source simultaniously. In that case, the simulation takes too long, advancing more slowly every time, as it would never end. He holds a Master of Science degree in electrical and computer engineering from University of California, Santa Barbara. Of course, if you know the syntax format, you can also enter it on the "Edit Text on the Schematic" screen. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Is there a trick I can use to overcome the 'up to three nested loops' limitation? This is useful for associating a name with a value for the sake of clarity and parameterizing your circuits. http://ltwiki.org/?title=Undocumented_LTspice#Stepping_a_Model, Powered by SMFPacks Advanced Attachments Uploader Mod. The only change that we need to make is to add a set of values for the variable parameter RL. Now I want to take that parameter and apply it to my components. So I wrote a C++ script to create the tables as (long) text files. https://groups.io/g/LTspice/topic/50201465#60860). The best answers are voted up and rise to the top, Not the answer you're looking for? The general idea (not the implementation) came from the LTspice yahoo group (e.g. We are going to work on this exercise in a slightly different order than the one asked by the exercise. I have an LCR circuit including voltage sources where I need to sweep more than three parameters (nested sweep) for a transient simulation. 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. LTspice is employed for this experiment. Notice Uin could be used as {Uin} in a voltage source or similar and so on. Open the Independent Voltage Source screen by right-clicking the signal source V1 of the schematic with the mouse. Something like this: Paul asked how to step two parameters at once. 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. heidi swedberg talks about seinfeld; voxx masi wheels review; paleoconservatism polcompball; did steve and cassie gaines have siblings; trevor williams family; max level strength tarkov; zeny washing machine manual; ltspice step multiple parameters. LTspice table function. Linear regulator thermal information missing in datasheet. (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).
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