I can't find the component, do I need to create the footprint for it?


#1

So I was looking for a LEM HLSR-P/SP3 current transducer in the component list. Can’t find it so do I need to create a custom component for it ?

Thanks.


#2

That particular part is so unique and so specialized that you will have to create both the schematic symbol and the footprint.

Dale


#3

Hi, Dale. Thanks for answering.

I got another question, do I need to use this to create the footprint?

Also if this is the one that I need to use then, which one is the diameter for the pads and the drill size.

Thanks again.


#4

Yeah, that’s the footprint information. Everything there is obviously in millimeters and it’s using a drafting syntax and notation that I’m not very fluent in. (My drafting tools still include the pen nibs for making your drawings permanent with India ink.)

Looks like the pads for the series current path are 3.1mm (125 mil) dia, with 1.6mm (63 mil) holes. They’re spaced on a 2.54mm (100 mil) pitch, so the pads actually overlap. I’d be tempted to draft them as rounded rectangles, to keep the edges a continuous, smooth line.

The pads for the other signals seem to be 1.9mm (75 mil) dia with 1mm (39 mil) holes. That hole size seems a little large - they may be using a large hole to absorb tolerances in the module’s packaging. I’d look at the package drawing and consider a smaller hole size - a size already in use elsewhere on your board. I wouldn’t try to run any traces between those pads using the specified dimensions.

Dale


#5

Thank you Dale for your detailed response.


#6

The dimensions in boxes are ‘Basic Dimensions’ and are the ideal numerical value, the real world dimension will differ from this, depending on tolerances.


#7

Thanks for the great reference & tutorial!

Dale


#8

Another goodie for my personal library. Thanks, have a :beer: on me.


#9

There is a library for these footprints - https://github.com/KiCad/Hall-Effect_Transducers_LEM.pretty

If you are willing to submit a pull request with this new footprint, please do! Maybe others can benefit from your hard work


#10

Thanks again Joan_Sparky.


#11

Thanks for the libraries. I created the footprint last night. I used guide provided by the other two users above.

What do you mean by pull request?


#12

This is the way to contribute to github projects.

  1. You need to create a github account
  2. Fork the repository in question
  3. Create a new branch (give it a meaningfull name. eg: Adding-part-xy ) on your personal repository
  4. Do your changes on this branch (add your footprint)
  5. Commit your changes to your online repo
  6. Open your repo in the browser and create a pull request.
    1. In the pull include the information what you changed
    2. Also include a screenshot of the part

The wiki page of the packages3d library gives a detailed explanation on how to contribute:
(The how to page of the kicad library is very similar but with less details.)


#13

okay, thanks for the info.