Doubling up tracks on different layers

David Ingebretsen wrote:

Michael Sansom wrote on Thu, 01 April 2010 09:24

Guys,

 

I've got a problem I hope someone can help me out with.  I have some

very high current traces on my PCB (15A and 30A).  I'm using 2oz copper

 

but in order to get track widths that aren't completely ridiculous I

need to double up the tracks on two layers.  I'm new at Eagle (last

used OrCAD PCB editor which is a stripped down version of Allegro) and

I can't seem to make this happen.  When I route the initial track on the

 

first layer naturally the ratsnest for this route disappears (since it

 

is now connected).  Eagle won't allow me to start a track on the second

 

layer because there is no longer an active ratsnest.  How do I get

around this?

 

This is also a generic issue.  If I want to start routing on a pin that

 

the ratsnest currently isn't touching (but it is unrouted, the ratsnest

 

is just terminated on a different unrouted pin) Eagle won't let me.

This is different from Allegro where I could start routing on any pin

and if it was unrouted the ratsnest would immediately snap to that pin.

 

  This is somewhat annoying since it is forcing me to route nets in the

 

order that Eagle decides to snap the ratsnest to instead of routing in

 

the order that is most logical to me.  I'm sure there is a way around

this, but I've yet to find it.

 

Thanks,

 

Michael

 

I can't help on the first issue, but for the second one, press and hold

ctrl when you are starting your trace and you can start at any location on

the net.

Also, remember, too, you can press down alt as well to use the alternate

grid spacing temporarily.

 

DAvid

Thanks to both of you.  Yes, I use the ALT key a lot to switch to my

minimum grid spacing and that works well but I wasn't aware of the CTL

key allowing me to start a line on a pin/pad that wasn't terminated in a

ratsnest line.

That first question is really important.  The ability to run the same

track on different layers is a key ability when doing layouts with high

current nets.  Doug seems to imply that using CTL might work in that

situation as well.  I'll try it and see what happens.

Moving from one layout package to another is always a pain as you get

trained to think in terms of whatever package you have the most

experience with.  After using Eagle for a week or so it seems that there

are many fine attributes of this package.  The ability to alter a

schematic and have the results show up immediately in the pcb layout

package is a huge plus.  And in terms of pure execution speed it seems

faster than Allegro in many places.  However, there are a few things

that I really miss.  Allegro would let me constrain my tracks to be

purely orthogonal with 45 degree bends, and would automatically keep

tracks vertical/horizontal as you routed across the board.  Also, it

would enforce spacing requirements in real time as you routed a trace

(so you didn't find out that you have tracks closer than your design

rules permit only after running a DRC).

All and all it is a very good value.  However, I would think that with

the addition of a few key features it could compete with anything out

there.  Would be interesting to know what sort of features are on the

road map for future releases.

-Michael

Quote:

Allegro would let me constrain my tracks to be

purely orthogonal with 45 degree bends, and would automatically keep

tracks vertical/horizontal as you routed across the board. Also, it

would enforce spacing requirements in real time as you routed a trace

(so you didn't find out that you have tracks closer than your design

rules permit only after running a DRC).

Hi,

To change the orthogonal bend style when routing, you can use the right

mouse button while you're drawing the trace.  Just keep cliking the right

button to change the angle style to what you like.

I don't know a way to enforce spacing from one wire to the next while

routing, I've always controlled this with grid, track-width, and being very

careful, but it's a pain.  PADs had a mode where it would "hold" the

routing to design rule spacings as you were doing it, but I haven't found a

way to do this in Eagle.

If anyone knows, I'd be very interested too.

Cheers,

Alex

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"Michael Sansom" <mssansom@hotmail.com> wrote in message

news:hpg1g0$lrj$1@cheetah.cadsoft.de...

I like Eagle and think it is a hell of a value for the money, but it is a

little frustrating that there are a few features found in other tools that

are missing that would take Eagle to the next level and allow it to

compete with almost any package out there.  Hopefully some of this will

get addressed in future releases.

People are not the same. Software is made by people for people. So it can't

be an application to please everyone. Eagle is made for people that love and

use Eagle. Some of them want to bring new features in this software, some of

them wants to keep-it as it is (even changing the version number is an

"almost acceptable change" for some of them )

And the "not so good" news is that Cadsoft is never hurry to implement

changes in their software (maybe the effort is too heavy, or they can't, or

they won't )

But as it is now, it's usable for much more than just routing a PCB with 3

resistors and an IC.

Alex Faveluke wrote:

Quote:

Allegro would let me constrain my tracks to be

purely orthogonal with 45 degree bends, and would automatically keep

tracks vertical/horizontal as you routed across the board. Also, it

would enforce spacing requirements in real time as you routed a trace

(so you didn't find out that you have tracks closer than your design

rules permit only after running a DRC).

 

 

Hi,

 

To change the orthogonal bend style when routing, you can use the right

mouse button while you're drawing the trace.  Just keep cliking the right

button to change the angle style to what you like.

 

I don't know a way to enforce spacing from one wire to the next while

routing, I've always controlled this with grid, track-width, and being very

careful, but it's a pain.  PADs had a mode where it would "hold" the

routing to design rule spacings as you were doing it, but I haven't found a

way to do this in Eagle.

 

If anyone knows, I'd be very interested too.

 

 

Cheers,

 

Alex

 

 

Yeah, I discovered the routing mode that enforced orthogonal tracks with

45 degree bends, and that does help.  However, if after routing a track

in this manner I then move/shove the track I loose my guarantee of

orthogonal lines and 45 degree bends, which is a bummer.

I've seen PADS and it's enforcement of spacing rules in real time while

routing is very much like Allegro's.  That feature tremendously speeds

manual routing and is a huge asset.  I don't believe that Eagle can

support this as it stands.  I don't know how PADS works in this respect

but Allegro would also enforce spacing rules when you moved/shoved

tracks after initial routing. i.e. if you shoved a track too close to

the adjacent track such that it violates the spacing constraints it

would either shove the adjacent track over (if it could without it

colliding with something else) or it would just not allow it to happen

and the track you were shoving would "bounce" off.  Again, great asset

to have when routing a dense board.  Both tools allowed you to easily

optimize your routing channel such that every track in parallel was

placed at the minimum spacing.

I like Eagle and think it is a hell of a value for the money, but it is

a little frustrating that there are a few features found in other tools

that are missing that would take Eagle to the next level and allow it to

compete with almost any package out there.  Hopefully some of this will

get addressed in future releases.

-Michael

Alex Faveluke wrote:

Quote:

Allegro would let me constrain my tracks to be

purely orthogonal with 45 degree bends, and would automatically keep

tracks vertical/horizontal as you routed across the board. Also, it

would enforce spacing requirements in real time as you routed a trace

(so you didn't find out that you have tracks closer than your design

rules permit only after running a DRC).

 

 

Hi,

 

To change the orthogonal bend style when routing, you can use the right

mouse button while you're drawing the trace.  Just keep cliking the right

button to change the angle style to what you like.

 

I don't know a way to enforce spacing from one wire to the next while

routing, I've always controlled this with grid, track-width, and being very

careful, but it's a pain.  PADs had a mode where it would "hold" the

routing to design rule spacings as you were doing it, but I haven't found a

way to do this in Eagle.

 

If anyone knows, I'd be very interested too.

 

 

Cheers,

 

Alex

 

 

Yeah, I discovered the routing mode that enforced orthogonal tracks with

45 degree bends, and that does help.  However, if after routing a track

in this manner I then move/shove the track I loose my guarantee of

orthogonal lines and 45 degree bends, which is a bummer.

I've seen PADS and it's enforcement of spacing rules in real time while

routing is very much like Allegro's.  That feature tremendously speeds

manual routing and is a huge asset.  I don't believe that Eagle can

support this as it stands.  I don't know how PADS works in this respect

but Allegro would also enforce spacing rules when you moved/shoved

tracks after initial routing. i.e. if you shoved a track too close to

the adjacent track such that it violates the spacing constraints it

would either shove the adjacent track over (if it could without it

colliding with something else) or it would just not allow it to happen

and the track you were shoving would "bounce" off.  Again, great asset

to have when routing a dense board.  Both tools allowed you to easily

optimize your routing channel such that every track in parallel was

placed at the minimum spacing.

I like Eagle and think it is a hell of a value for the money, but it is

a little frustrating that there are a few features found in other tools

that are missing that would take Eagle to the next level and allow it to

compete with almost any package out there.  Hopefully some of this will

get addressed in future releases.

-Michael