Using Net in Eagle

Hi Edmund,

the WIRE command is meant to draw simple lines as for symbols or a frame in the schematic drawing. You can use it in any layer, even in layer Nets. If the wire starts and ends exactly in a pin's conection point and is drawn in layer Nets, it behaves like an electrical connection.

But originally the NET is meant to draw  electrical connections. The benefit of NET is that the connection is always drawn in layer Nets. If you end a net at a pin connection point the net drops from the mouse cursor (a wire wouldn't). This indicates that the net is connected to the pin. Second option is that a junction (a connection point) is automtically set, if you connect two nets.

The WIRE command in the board editor is meant to draw lines in any layer. It is possible to connect two pads with a WIRE if it begins and ens exactly in the pads/smds origin, but the correct way is to use the ROUTE command, provided that you have drawn a schemtic before and that there are already signals (airwires) connecting pads/smds in your layout. ROUTE grabs/jumps automtically into the center of the pad/smd and so we are sure to have a well-defined connection between them.

If you don't have a schematic and started designing only a  board, you can use the SIGNAL command first to establish the connection (airwires) between your components. Then use ROUTE for laying out the tracks.

Hope this info helps.

Richard

Dear Richard,

thanks for the reply. But I am confused by the Eagle Tutorial Page 27 which states the following point:

Do not use the WIRE command to draw net or bus lines in the schematic.
Use NET or BUS instead!

Use ROUTE and not WIRE to dissolve airwires to tracks in the Layout
editor. Otherwise EAGLE would not set vias automatically when changing
signal layers.

But from your reply. you were saying that " If the wire starts and ends exactly in a pin's conection point and is drawn in layer Nets, it behaves like an electrical connection."

Please do enlighten me on this and appreciate your efforts.

Cheers

Edmund

Dear Richard,

thanks for the reply. But I am confused by the Eagle Tutorial Page 27 which states the following point:

Do not use the WIRE command to draw net or bus lines in the schematic.
Use NET or BUS instead!

Use ROUTE and not WIRE to dissolve airwires to tracks in the Layout
editor. Otherwise EAGLE would not set vias automatically when changing
signal layers.

But from your reply. you were saying that " If the wire starts and ends exactly in a pin's conection point and is drawn in layer Nets, it behaves like an electrical connection."

Please do enlighten me on this and appreciate your efforts.

Cheers

Edmund

Dear Richard,

thanks for the great information. Now I get what you mean.

Thanks for the insight.

Appreciate that.

Cheers

Edmund

Hello Edmund,

NET in the schematic and ROUTE in the board offer some simple benefits compared to WIRE.

NET:

It is always in the Nets layer - you don't have to care about the layer you draw in

The line width is always the same - you don't have to care about

Ending a net exactly in the pin connection point let the net drop from the mouse cursor - you can be sure that the connection is established

Connecting two nets results in a junctino - you can be sure that your schematic is proper readable

We do not forbid to use the WIRE command,  we strongly recommend to use NET. It makes things easier and gives more reliability in what you do.

It's less error-prone.

The same with ROUTE:

The trace always begins and ends in the center of the pad or SMD - you don't have to care about grid

You can use the magnetic pads functionality - results in a proper layout

If you change layers, vias will be set automatically - you don't have to deal with them separately

The same as in the schematic here. ROUTE offers benefits and assurance.

Richard