modify resistor footprint

[johanP]

I would like to change the resistor footprint for a student lab where the pads have to be made larger than the regular size. I cannot find a good match in the existing resistor footprints. How can I add a home-made footprint to the virtual component resistor?

[NatashaB]

This depends on the version of Multisim you are using.  If you are using V10.1:

1. Create your custom resistor footprint in Ultiboard and save to your User Database
2. In Multisim, place down a resistor
3. Double-click on the resistor and select Edit Footprint
4. Choose Select from Database
5. Browse through the User Database in the Select a Footprint dialog; you should see the footprint you created in Ultiboard.

If you are using an older version, you will need to click Add from the Select a Footprint dialog, and enter the footprint name exactly as you saved it in Ultiboard.  There is a KnowledgeBase article available here for further information: http://digital.ni.com/public.nsf/allkb/B0077C481ED8E47B862572110061FA6B.

Hope this helps!

[johanP]

When I try backward annotation, Multisim doesn't recognize my modified footprints. (I've copied the existing resistor footprint ex. R0207R10, modified the pads, and then saved it as a new PCB-part ex. R0207R10_100/0.7). When using backward annotation all my modified footprints are removed. How can I use backward annotation with modified footprints?

Best regards,

Johan Pattyn

[NatashaB]

This is just a hunch, but I think the issue could be that you have created the footprint in Ultiboard, but haven't created the link to it in Multisim.  The latest version of Multisim creates this link automatically, but if you are using an older version, you will need to do it manually.  Which version of Multisim are you using?

Multisim needs a reference to the footprint in Ultiboard to be able to associate the correct footprint to your component in Multisim.  This is done in the Select a Footprint dialog.

The link above should help you create the association between Ultiboard and Multisim.  Did you get a chance to run through it?

[johanP]

I use the circuit design suite version 10.1 Education Edition. I can create the link from multisim to ultiboard for my modified footprints. If necessary I have also modified the pinout, ex. 1;2; in multisim links to A;C; in Ultiboard. Forward annotation works satisfactory.

I tested a small circuit with only components from the master database.  When I change the footprint in Ultiboard, after backward annotation the component is removed in multisim. So it has nothing to do with the use of custom footprints. This is very disturbing. Ex. When routing my PCB I see that the order of pins in my created footprint for a USB socket is wrong. So I modified the pin names in my footprint. After using change/update footprint I can no longer use backward annotation or the according component in multisim will be removed. I think I can fix this by manually deleting the log-file. I've succeeded using the backward annotion for deleting a pin from a net in the netlist editor in ultiboard. But when the changes are somewhat more elaborated ex. changing a resistor from parallel to serial, multisim doesn't succeed in making the correct changes. So I think I would need to make the changes step by step; backward annotate after each step and delete the log file before making the next step.

Best regards,

Johan Pattyn 

[johanP · Accepted solution]

What I have read on http://zone.ni.com/devzone/cda/tut/p/id/7321#toc6 concerning backward annotation confirms what I have found out:

"the back annotation process does have limitations upon what changes can be effectively transferred back to the schematic".

[electronifyindia]

Hi johanP,

To create a custom resistor footprint with larger pads for your student lab, follow these steps:

1. Create a New Footprint: Use your PCB design software’s footprint editor to create a new resistor footprint. Adjust the pad sizes as needed for your lab requirements.
2. Save the Footprint: Save this new footprint with a unique name to distinguish it from the standard footprints.
3. Assign the Footprint: In your component library, assign this custom footprint to the virtual component resistor.

For detailed tutorials and additional support, visit Electronify India.

Best of luck with your project!