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Advice please - what grid settings to use ?

e14 Contributor

Following on from my last posting "Nets won't connect to pins".

 

Whats the best way to choose grid settings? I seem to work with a mix of

components that either use an old fashioned 0.1 inch pitch, or newer SMC

metric components based on a 0.5 mm pitch. How should I set up the

schematic grid to make it as easy as possible to connect both sets of

components?

 

On a similar line, when I place a new component from a library onto a

schematic, I assume it's the cross-hairs on the component that will

actually align with the grid?

 

If this is correct, then I guess that when I create a new library component

I need to make sure that the pins align with the same grid that the

cross-hairs are on? If I create a component with a grid of 0.05 inch, and

then add pins at 0.1 inch intervals (say 0.05, 0.15, 0.25 inches etc). Then

if I use this component on a schematic with a 0.1 inch grid, the pins will

never align with the grid and I'll never manage to connect them to a net

(unless I change the grid settings of course)

 

All advice appreciated!

 

Thanks

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  • Lima schrieb:

     

    Whats the best way to choose grid settings? I seem to work with a mix of

    components that either use an old fashioned 0.1 inch pitch, or newer SMC

    metric components based on a 0.5 mm pitch. How should I set up the

    schematic grid to make it as easy as possible to connect both sets of

    components?

     

    First of all, never confuse the sizes and grid settings of the

    schematic with those of the board! Metric packages and/or small pitch

    are in absolutely no way related to the sizes and grids in the schematic.

     

    On a similar line, when I place a new component from a library onto a

    schematic, I assume it's the cross-hairs on the component that will

    actually align with the grid?

     

    All pins of any symbol should align with the grid used within the

    schematic - referenced to the symbols origin. A pretty common standard

    in EAGLE is to use 0.1 inch here, and all libraries coming with EAGLE

    (should) use that value.

    If you then place such symbols in your schematic using the same grid,

    every pin will be on grid and can easily be connected.

     

    Regardless of the package metrics, there is absolutely no need to ever

    use a different placement grid in the schematic. However, for labels and

    nets I often use smaller grids of 25 and 50 mils, for which I have set

    the alternative grid to 25 mil with a multiplier of four (so the grid

    display doesn't change when switching to it).

     

    If this is correct, then I guess that when I create a new library component

    I need to make sure that the pins align with the same grid that the

    cross-hairs are on? If I create a component with a grid of 0.05 inch, and

    then add pins at 0.1 inch intervals (say 0.05, 0.15, 0.25 inches etc). Then

    if I use this component on a schematic with a 0.1 inch grid, the pins will

    never align with the grid and I'll never manage to connect them to a net

    (unless I change the grid settings of course)

     

    Exactly. So take care to always use the same grid.

     

    Tilmann