Preferred power supply connections?

Olin wrote on Thu, 25 February 2010 07:16

dingebre wrote on Wed, 24 February 2010 21:57

This image kind of shows what I mean.

 

No, it shows a mess.  There is rotated text all over the place, labels

overlapping other labels and parts, and missing values.  If you don't

care about your design, there is no reason I should either.

Hi Olin, you're reading too much into the "design". This is not a real

schematic.

I'm only illustrating the power connections. I am showing the +/-15 volts

to the plug, and one way I was thinking to do the other power nets. I don't

even know if this design is electrically "real"

I only ask a little patience. I'm very new to using Eagle and want to learn

good habits. Would you maybe take a second look? I'd like some advice about

how to handle the power nets on the "real" circuits I'd like to work on.

Should I do it kind of like in that illustration? Use the supply library

+/- 15 for the plug and then a generic supply symbol to connect the +/-

supplies on the components? Or is there a better way?

Thanks for looking Olin.

David

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dingebre wrote on Thu, 25 February 2010 11:42

Hi Olin, you're reading too much into the "design". This is not a real

schematic.

 

I'm only illustrating the power connections.

It is still a good idea to keep in mind that neatness counts, especially

when you are presenting to others.  Some may look past that, but why allow

it to be a issue when it would only have taken a extra minute to make

things more readable?

Quote:

I only ask a little patience. I'm very new to using Eagle and want to

learn good habits. Would you maybe take a second look? I'd like some

advice about how to handle the power nets on the "real" circuits I'd like

to work on.

I don't use specific parts at all to label power nets.  I don't treat power

nets any different from other nets that are drawn in separate pieces,

although I've seen others use explicit power symbols commonly.  In Eagle,

nets in the schematic are automatically connected if they have the same

name.  To show airwires in a Eagle schematic, I name the nets and then use

DRAW LABEL to show the net name in the schematic.  It's important to use

DRAW LABEL instead of TEXT because DRAW LABEL shows the true net name as

Eagle understands it.  If you change the net name, the text drawn with DRAW

LABEL will automatically change.

For power nets I use names like "5V", "-12V", "BATT", or whatever I think

will be most descriptive in context of that schematic.  I also like to show

power connections on top, ground on the bottom, with signal from left to

right to the extent this can be reasonably done.  Keep in mind that the

schematic is not only to define the machine readable connections to Eagle,

but it is also the primary documentation of your circuit to humans.  As

such, neatness and clarity are very important considerations.

Quote:

Should I do it kind of like in that illustration? Use the supply

library  +/- 15 for the plug and then a generic supply symbol to connect

the +/- supplies on the components? Or is there a better way?

You'll probably find as many opinions as people.  There are several

reasonably "right" ways.  I've tried to explain what I do, but I recognize

there are other ways that others prefer.  As long as Eagle understands the

connections, there aren't hidden gotchas for making changes, and your

circuit is easy to understand from the schematic, then it's a acceptable

method.

You can take a look at http://www.embedinc.com/products/usbprog/eusb3.pdf

as a example of how I do things.  The first page is the main power supply.

Note all the named wires ending at the right side because the logical flow

is out from the power supply.  You can see various other places in the

schematic that connect to these power rails, usually coming in from the top

or left as a simple visual reference that the power is coming in instead of

being produced there.  Note that no explicit power symbols were used, just

named nets with carefully placed labels.

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dingebre wrote on Thu, 25 February 2010 11:42

Hi Olin, you're reading too much into the "design". This is not a real

schematic.

 

I'm only illustrating the power connections.

It is still a good idea to keep in mind that neatness counts, especially

when you are presenting to others.  Some may look past that, but why allow

it to be a issue when it would only have taken a extra minute to make

things more readable?

Quote:

I only ask a little patience. I'm very new to using Eagle and want to

learn good habits. Would you maybe take a second look? I'd like some

advice about how to handle the power nets on the "real" circuits I'd like

to work on.

I don't use specific parts at all to label power nets.  I don't treat power

nets any different from other nets that are drawn in separate pieces,

although I've seen others use explicit power symbols commonly.  In Eagle,

nets in the schematic are automatically connected if they have the same

name.  To show airwires in a Eagle schematic, I name the nets and then use

DRAW LABEL to show the net name in the schematic.  It's important to use

DRAW LABEL instead of TEXT because DRAW LABEL shows the true net name as

Eagle understands it.  If you change the net name, the text drawn with DRAW

LABEL will automatically change.

For power nets I use names like "5V", "-12V", "BATT", or whatever I think

will be most descriptive in context of that schematic.  I also like to show

power connections on top, ground on the bottom, with signal from left to

right to the extent this can be reasonably done.  Keep in mind that the

schematic is not only to define the machine readable connections to Eagle,

but it is also the primary documentation of your circuit to humans.  As

such, neatness and clarity are very important considerations.

Quote:

Should I do it kind of like in that illustration? Use the supply

library  +/- 15 for the plug and then a generic supply symbol to connect

the +/- supplies on the components? Or is there a better way?

You'll probably find as many opinions as people.  There are several

reasonably "right" ways.  I've tried to explain what I do, but I recognize

there are other ways that others prefer.  As long as Eagle understands the

connections, there aren't hidden gotchas for making changes, and your

circuit is easy to understand from the schematic, then it's a acceptable

method.

You can take a look at http://www.embedinc.com/products/usbprog/eusb3.pdf

as a example of how I do things.  The first page is the main power supply.

Note all the named wires ending at the right side because the logical flow

is out from the power supply.  You can see various other places in the

schematic that connect to these power rails, usually coming in from the top

or left as a simple visual reference that the power is coming in instead of

being produced there.  Note that no explicit power symbols were used, just

named nets with carefully placed labels.

--

Browser access to CadSoft Support Forums at http://www.eaglecentral.ca