It is important to understand that if you place the ground reference in a different point you are going to get different results. After simulation, when you move the cursor close to the schematic wiring, the cursor changes to voltage probe. 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. Perform parametric analysis using the schematic in the following article. For example, combine parameter A and parameter B into a new parameter, (A*100+B), and sweep that. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. Is there a single-word adjective for "having exceptionally strong moral principles"? The Thevenin resistance is equal to RL for maximum power, in this case Rth = 12. Can I have two (or more) different symbols for the same LTspice schematic? After simulation, the graph pane will appear at the top of the schematic with the default settings of LTspice. 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. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? By computing 1-u(Temp) the temperature coefficient tc3 is effective only if Temp < 0 C. This is not what OP is asking about. But this wouldn't vary the parameters independently. On the output graph, add the signals of interest to that graph (in this case Vo) and add a cursor. Linear regulator thermal information missing in datasheet. What LTSpice does is automatically set each step to have a certain color automatically. Click Run on the toolbar to run the simulation. Add a .step command via a SPICE directive that specifies the steps for the parameter by a linear, logarithmic or list of values. For the types of analysis, please see the following article. 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. This multiple value parameter might have values with single quote, such as: abc, efg's, sms dio, 'you's dfd. In this article, we only used the waveform viewer to check the voltage waveforms of V(OUTPUT) with the voltage probe. Your answer is a simple tutorial on a basic LTspice concept. parameter combination) was used for each simulation. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. Menu Visit Stack Exchange Tour Start here for quick overview the site Help Center Detailed answers. Here is a list of some hotkeys for creating your schematic: R: Place resistor. If you just want to simulate the 3 scenarios I wouldn't bother doing it with spice. You should now see .tran 10m at the bottom of the screen. Its quite a . I found most of the solution for passing multiple value to stored procedure is to create a user defined function to put the string to a table, then grab the value from table to stored procedure. This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing. One parameter sweep/step can control multiple component values through expressions. A place to ask questions, discuss topics and share projects related to Electrical Engineering. https://groups.io/g/LTspice/topic/50201465#60860). As regards your second question, X would be the different indexes that let me access the table's values. 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. Figure 1. For LTspice, use tables to define params. Another way to simulate a set of values at the same time is to use the increasing order option of the .step command. 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. I am not sure if my question was well understood (yes I did find other similar posts but no applicable answers). Confirm that ".step" of the dot command is displayed as ".step param R2 100 400 100". Note: To download the simulation files provided in this article, the reader must have LTSpice installed. Using Kolmogorov complexity to measure difficulty of problems? Thanks for contributing an answer to Electrical Engineering Stack Exchange! Open the edit screen of resistance R2 by "right clicking" the resistance R2 of the schematic with the mouse. 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. This is the setting for performing a parametric analysis that changes the variable R2 from 100 to 400 ohms in 100 ohm linear steps. The command ".step" performs parameters sweeps. We are almost there. In this article, it was placed near source V1. D: Place diode. For instance, plot V in a circuit with R=1 and C=1, then plot V with R=2 and C=2, then plot V with R=3 and C=3, etc. This is useful for associating a name with a value for the sake of clarity and parameterizing sub circuits so . To understand the LTspice Model Parameters of Components we shall first understand the .param directive used in LTspice simulation software. To learn more, see our tips on writing great answers. They are defined with the .op SPICE directive " .param <name> = <value> ". Why does it seem like I am losing IP addresses after subnetting with the subnet mask of 255.255.255.192/26? Visit Stack Exchange Tour Start here for quick overview the site Help Center Detailed answers. Input Name of parameter to sweep: R2, Nature of sweep: Linear, Start value: 100, Stop value: 400, Increment: 100. Press keyboard letter "T" to show the spice directive. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? 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. It described a complete circuit, so I extracted just the SCR description. It would take time to add and adjust values using the .step list method. 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. We are going to work on this exercise in a slightly different order than the one asked by the exercise. Instead a combination of parameters using SPICE directives needs to be called for help . The best answers are voted up and rise to the top, Not the answer you're looking for? Are you sure you wish to repost this message? I guess I'll just have to export the data and plot it elsewhere. Visitors have the right to withdraw their consent. Note: For this approach to run without errors, make sure that the size of the list is equal to number of variable parameters. LTspice parametric sweep: how to force the simulator to continue with the next step? LTspice table function. Linear Algebra - Linear transformation question. Make sure the "SPICE directive" is selected and enter ".step". 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. You can break that back out into A and B as it executes. Here is an example waveform response of an RC circuit, for which the capacitance is stepped through three values. It is performed simultaneously with transient analysis, AC analysis, DC sweep analysis, etc. Lastly the .op command drives the operation. In LTspice parameters are variables that can be reused throughout the schematic. 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. rev2023.3.3.43278. However, to my knowledge it is not possible to achieve what you asked for. How do/should administrators estimate the cost of producing an online introductory mathematics class? This video provides an overview of how to use the .STEP command to perform repeated analysis of a circuit in LTspice. Normally, LTspice sets the resistance element parameter to a constant such as R = 10. In this article, we will briefly introduce the types of analysis that can be performed with LTspice. In this article, we will explain in detail the parametric analysis(.step) method in LTspice. 2023 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} LTspice IV: Using the .STEP Command to Perform Repeated Analysis. 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 . Are you sure you wish to repost this message? For additional information you may view the cookie details. To learn more, see our tips on writing great answers. After simulation, the graph pane will appear at the top of the schematic with the default settings of LTspice. LTspice: How can I show multiple probes with waveforms using stepping parameters in different colors? http://tech.groups.yahoo.com/group/LTspice/files/%20Tut/Stepping%20to%20the%20max/. 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. 2. 2023 this is how I roll it in 1 run (same method as what mr stilltrying said). rev2023.3.3.43278. Is there a trick I can use to overcome the 'up to three nested loops' limitation? You need to replace this with your parameter designator; put that inside {} brackets, e.g. 3: R1 = 1 k\$\Omega\$, R2 = 1 M\$\Omega\$. The Group moderators are responsible for maintaining their community and can address these issues. It only takes a minute to sign up. Click SPICE Directive on the toolbar to display Edit Text on the Schematic screen. For example, combine parameter A and parameter B into a new parameter, (A*100+B), and sweep that. For this particular example, the increasing order option goes from 1k to 10k in increment steps of 2k. MathJax reference. 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). 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. To plot a specific answer, right click on the graph, go to View and select Select Steps. 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. Why does LTspice XOR gate have more than two inputs? Check that SINE is selected and DC offset [V]: 0, Amplitude [V]: 2, Freq [Hz]: 500 is input. Subject of the new topic: Subscribe today! We are commenting the second Spice directive for now. Then you use .include and .step param and the TABLE function in LTspice to perform the sweeps. 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. Why does LTspice XOR gate have more than two inputs? Can be one line. Subject of the new topic: It's important to have all .step commands in one text box. It only takes a minute to sign up. Groups.io, Is there a way to have LTspice step multiple parameters as a, --- In LTspice@, "dan.friedrichs" . The addition of the curly braces around the variable is important as it tells LTspice IV that X is a parameter. LTSpice doesn't know what your talking about until you do that bit. Thankfully, LTSpice generates data when doing a transient analysis with multiple stepping parameters fairly easily. The specialty shows in the expression 1-u(Temp) in the last line. 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. During homework exercises or labs, sometimes you need to analyze the circuits for different components values. 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. The probe cursor indicates which 'key' (i.e. Relation between transaction data and transaction id. This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing. 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. 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. Use MathJax to format equations. Once you run and view your simulation results in the waveform pane you can review the step information of a particular trace by attaching a cursor (click onto the trace label), using the up and down arrow keys to navigate the steps and then right-clicking onto the cursor to view the step information. 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: . I have tried setting X to 0 1 2 instead of 1 2 3, but that does not work either. 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. Difficulties with estimation of epsilon-delta limit proof, Follow Up: struct sockaddr storage initialization by network format-string. Now I want to take that parameter and apply it to my components. The LTSPICE function u(x) is a step function with u(x)=1 for x > 0 and u(x)=0 else. You should see ".step param R2 100 400 100" at the bottom of the screen. Notice Uin could be used as {Uin} in a voltage source or similar and so on. The best answers are voted up and rise to the top, Not the answer you're looking for? For more information on how to use the .step command to improve your understanding of a schematic, review the Help Topics in LTspice IV. Click "SPICE Directive" on the toolbar to display "Edit Text on the Schematic" screen. Does a summoned creature play immediately after being summoned by a ready action? of runs I hope I'm being clear. 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. L: Place inductor. parameters through use of the Component Attribute Editor. Model Statements: Some devices, such as, transistors and diodes require information on the device in order to make calculations. 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. Lets start by creating a user-defined variable in LTSpice. The only change that we need to make is to add a set of values for the variable parameter RL. 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. 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. The .step command causes an analysis to be repeatedly performed while stepping through a model parameter, global parameter or independent source. Trying to understand how to get this basic Fourier Series. which parameter combination corresponds with which waveform). For How to set up detailed transient 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). For multiple lines in the "op" editor window use CTRL+M to keep all params in same textbox. 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 . I could open up the plot legend that shows the color of each point, but I don't see anywhere to change these settings. 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 LTspice requires setting of the signal source when simulating. After we finish updating our website, you will be able to set your cookie preferences. Asking for help, clarification, or responding to other answers. Would the magnetic fields of double-planets clash? 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. You've likely already given it a value, eg 1k0. #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. 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. This is useful for associating a name with a value for the sake of clarity and parameterizing your circuits. This is useful if you want to maintain a relation or control some indirect physical property of the design like a current or filter property. Setup the transient command as below. Of course, it does not matter if you enter 0.01 instead of 10m without using auxiliary units. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. communities including Stack Overflow, the largest, most trusted online community for developers learn, share their knowledge, and build their careers. (I'm using the .op command). .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) 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. How to use Slater Type Orbitals as a basis functions in matrix method correctly? So I wrote a C++ script to create the tables as (long) text files. Are you sure you wish to delete this message from the message archives of LTspice@groups.io? The command .step performs parameters sweeps. Then use that parameter's values to control the other. 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. It is necessary to set the part which changes the parameter in parametric analysis. flower arranging classes northern virginia. In this case, the resistance value is varied from 1k to 10k. Doesn't analytically integrate sensibly let alone correctly. 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. The simulation time varies depending on the size of the circuit. For this exercise, we have 2 variable parameters, Vs and R, which gives a total of 4 possible solutions. Is it possible to step 2 parameters together? I had the sense that LTSpice does not support this, but I wanted to bounce this off of some other people first. One of those flavors is the ability to include a list of values for your variable name. You are missing a comma in the Vac table after the pair 3,200V. How to pass parameters to subcircuits in LTSpice with the include statement? In this article, we will introduce the "Initial Settings" when installing the latest version of LTspice XVII. Run the simulation and you should get the same results as in Figure 3. 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. Read more about our privacy policy. What sort of strategies would a medieval military use against a fantasy giant? Whats the grammar of "For those whose stories they are"? After we finish updating our website, you will be able to set your cookie preferences. 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). 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 One parameter sweep/step can control multiple component values through expressions. Groups.io. Now lets change the values of RL automatically and analyze the results. Open the Independent Voltage Source screen by right-clicking the signal source V1 of the schematic with the mouse. 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. You can duplicate this by taking the text at the end of this section and saving it as a file in your LTSpice Click Simulate-Edit Simulation Cmd in the menu bar to open the Edit Simulation Command screen. 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. and what would happen then? The .param directive allows the creation of user-defined variables. For instance, the forward voltage of a diode will change over different temperatures, the VBE of transistors, the RDSon of MOSFET and so on. 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.