I have created a femm model and would now like to display a Blx graph like this. Anyone know how I can do that?
You can use Octave (free software) and a script to plot BL and inductance over excursion.
There is a sample script on the FEMM website (getblcurve.m) but please note that the script has (or had) a small bug that was relatively easy to fix if I remember correctly. At the beginning of the script, dX is declared as a variable and set to 1mm. But in the script itself a fixed value of 1 is used instead of the dX variable, so if you change the value for dX nothing actually changes in the simulation. Changing the fixed value for dX solves this so you can use different increments.
https://www.femm.info/wiki/Woofer
You need to download Octave, setup your FEMM file according to the info in the above link and you need to enable FEMM to be driven by Octave once in the octave command line. Then run the script and make sure the FEMM file is in the same folder as the script and is named correctly so Octave can find it.
It will probably be a pain to get it running but if you stick to the instructions you should be fine.
There is a sample script on the FEMM website (getblcurve.m) but please note that the script has (or had) a small bug that was relatively easy to fix if I remember correctly. At the beginning of the script, dX is declared as a variable and set to 1mm. But in the script itself a fixed value of 1 is used instead of the dX variable, so if you change the value for dX nothing actually changes in the simulation. Changing the fixed value for dX solves this so you can use different increments.
https://www.femm.info/wiki/Woofer
You need to download Octave, setup your FEMM file according to the info in the above link and you need to enable FEMM to be driven by Octave once in the octave command line. Then run the script and make sure the FEMM file is in the same folder as the script and is named correctly so Octave can find it.
It will probably be a pain to get it running but if you stick to the instructions you should be fine.
Thanks in any case 🙂 I haven't found the bug yet, but even without it it won't work for me because I can't manage the Kelvin Transformation boundary. I can't quite follow his instructions and unfortunately you can't download his FEMM file in order to have the whole thing more visually :/
The link to download the FEMM file is literally at the bottom of the page. 😎
As for the 'bug', it shouldn't be that hard to find. Just find the part in the code where it moves the voice coil through the gap. Replace the 1 with dX and you're done.
I think it's this line. Just replace the 1 with dX and you're good to go. But to be honest, if you are going down this road, a bit of dedication would be helpfull. The answers are all there, I found them so there is no reason you can't. Only thing standing between you and reaching your goals is... you
I've done everything so far, but I don't have that much experience with Octane, when I run the script a temp.femm is created and opened by my model. But I don't see any graphs or values there now. Do I have to click something else or how can I display the result now? 😀The link to download the FEMM file is literally at the bottom of the page. 😎
As for the 'bug', it shouldn't be that hard to find. Just find the part in the code where it moves the voice coil through the gap. Replace the 1 with dX and you're done.
I think it's this line. Just replace the 1 with dX and you're good to go. But to be honest, if you are going down this road, a bit of dedication would be helpfull. The answers are all there, I found them so there is no reason you can't. Only thing standing between you and reaching your goals is... you
Yeah those things happened to me too, you just have to stick to it untill it works. And if it doesn't work then the command pane usually shows you some kind of reason why it won't work. And I also had litteraly zero experience with Octave untill I needed it for this. Kudos to you for making it work. Every day is a great day to suck at something new