How to create a generic part


#1

Hi,

I’m trying to create a generic resistor with european symbol (rectangle). But even by starting to create my part from an existing generic part, once created, it is no more generic. I can no more change its value on my schematic.

Am I doing something wrong ?


#2

Hmmm I’m not sure but generic parts are supported.

If you place the generic resistor on the schematic and double-click to edit it, the properties list should allow you to put any value in it, along with any part number once you know what part to buy.


#3

Hi,
Thanks for response.
The problem is that in my modified generic resistor, I’m no more able to modify any of its value like I can on standard generic parts.


#4

The only workaround I found is to define a new attribute resistance (same name as the original).
Set the original attribute as unvisible and set the new as visible.
This new attribute can be edited…
As I’m new to upverter, I don’t know what are the side effects that this hack may have :wink:


#5

Hi @svetsch

Yes, we do not allow core attributes to be edited on components so that the components get corrected in library … in hopes that we will approach a complete library over time.

There will not be any major side effect, just that it might appear wrong in the BoM view/export.

Out of curiosity, why are you using a made generic resistor instead of the built in generic. I would love to figure out how we can make generics better so you do not have to use this work around :slight_smile:

Michael


#6

Hi,

It is just because I prefer the european style of resistor (simple rectangle) instead of the american one.
Samuel


#7

Hi,
A related question.

We got feedback from our board manufacturer/assembler that the 0402 footprint for the “Generic resistor” and “Generic cap” that we used extensively in our design is NOT suitable for manufacturing. The problem is that the 0.5mm distance between pads’ inner edges is too large.
After a long search we found component footprints should be following IPC7351B, which Upverter doesn’t seem to be following for generic components.
When we tried to fork a generic resistor part to change the footprint, we can go through the whole process, see the resulting change on our layout, but after a while (less than an hour) the layout reverts to the previous footprint. When clicking on part in schematic, it represents the
modified footprint. Behavior is very counter intuitive - how can we trust the tool if it automatically reverts parts in layout, but not in the parts dBase (it should do neither)?

What is recommended procedure for creating a part so that we can swap out all our 0402 footprints.

It would be very useful to at least carry over the component values (ie avoid defining a “shadow” resistance value as suggested above. Similarly, creating a completely new part doesn’t appear to allow creating attributes (like resistance, capacitance and voltage) that can be viewed in the schematic and copied over during a swap.

Best of all would of course be if generic parts would be aligned with IPC7351 so we don’t have to fiddle around with generic part variants, but we need a short term workaround until that happens.

Note; IPC7351B isn’t publicly avail, but we found a nice KEMET doc that provides guidance.
KEMET
The above cited inter-pad distance should be 0.28mm per their doc.