Placing variables on a schematic

Altair Forum User
Altair Forum User
Altair Employee
edited August 2023 in Community Q&A

New user here but how does one place variables within easy reach on the schematic? For example, say you have several FETs and you want to vary Rds_on for the devices. Is there a way to place a variable "Rds_on" in the schematic for easy changing? Using v 11.0.3

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2023

    Hi Dennis,

    What you are looking for is the parameter file element. This is found in "elements->other"

    The parameter file is a text based file that can contain variable definitions for you Rdson variable you would use a statement like this

    Rdson = 100m

    In each of your FET models you would use 'Rdson' as the value and the parameter file definition would assign 100m to each one. Be careful it is CaSe SenSitIVE. As above engineering units are allowed or you can use 10e notation.

    m = 10e-3
    k = 10e3
    M = 10e6
    u = 10e-6
    etc…

    Have you had a chance to see any of the tutorial videos? Parameter files are used in many of them.

    Also please have a look in the examples folder, the are examples that use parameter files throughout, mostly in the motor drives folder.

    Finally, please have a look in the user manual at the use of the parameter file, you are allowed to insert math expressions and use conditional logic in them.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2023

    Alright, I found this parameter file thing so thanks. I thought that would be for external files but apparently not. I have gotten very used to ltspice format so a little learning here on my part.

    I have looked through some of the example files but I guess I did not look through enough.

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