Same net but different net class with Eagle

Fabrizio,

Look in the shorts.lbr file.  It consists of two SMD pads that overlap. 

By putting a short in series with your smaller resistor, it forms two

different nets.  The net between the short and the resistor could be

assigned a different class allowing the narrower trace.  I can send a

shorts library to you.  Olin Lathrop is the original author, and I've

added a couple of my own.  Olin has published it on the Internet, which

is where I found it years ago.

My primary use of shorts is to connect different grounds together.  i.e.

I'll have a DGND, AGND, and HVGND representing grounds used in different

areas of a design (digital, analog, and high voltage).  In the end, all

these grounds need to be connected together.  I'll connect DGND to GND

through a short, then AGND to GND, and HVGND to GND.  Just plain old GND

will be routed back to the battery, or power supply or whatever.

Of course, you could use the narrower trace just as you have it now. 

When you do the DRC, you can approve the error it generates and it'll

never bother you again... at least until you move it.

HTH,

    - Chuck

On 4/16/19 02:38, Fabrizio Boco wrote:

I have a trace which powers an external device and with a large size because it carries a relative high current (more than 1A).

Along this trace I have a small value resistor to monitor the flowing current.

The resistor is connected to an ADC to measure current. The traces between the resistor and the ADC can be smaller than the power traces because not much current flows there.

I am not able to use two different net classes for the power trace and for the ADC traces. A soon as I change the class of the power trace, the sensors traces get the same net class and viceversa.

I have also tried to put a 0 ohm resistors along the sensor traces but this doesn't help neither.

Can anyone help me with this issue?

Thx

 

--

To view any images and attachments in this post, visit:

https://www.element14.com/community/message/274385

Fabrizio,

shorts.lbr can be found at

http://www.diymodules.org/eagle-show-library?type=usr&id=1012210749&part=shorts.lbr

HTH,

    - Chuck

On 4/17/19 13:54, Chuck Huber wrote:

Fabrizio,

 

Look in the shorts.lbr file.  It consists of two SMD pads that

overlap.  By putting a short in series with your smaller resistor, it

forms two different nets.  The net between the short and the resistor

could be assigned a different class allowing the narrower trace.  I

can send a shorts library to you.  Olin Lathrop is the original

author, and I've added a couple of my own.  Olin has published it on

the Internet, which is where I found it years ago.

 

My primary use of shorts is to connect different grounds together. 

i.e. I'll have a DGND, AGND, and HVGND representing grounds used in

different areas of a design (digital, analog, and high voltage).  In

the end, all these grounds need to be connected together.  I'll

connect DGND to GND through a short, then AGND to GND, and HVGND to

GND.  Just plain old GND will be routed back to the battery, or power

supply or whatever.

 

Of course, you could use the narrower trace just as you have it now. 

When you do the DRC, you can approve the error it generates and it'll

never bother you again... at least until you move it.

 

HTH,

    - Chuck

 

 

On 4/16/19 02:38, Fabrizio Boco wrote:

I have a trace which powers an external device and with a large size because it carries a relative high current (more than 1A).

Along this trace I have a small value resistor to monitor the flowing current.

The resistor is connected to an ADC to measure current. The traces between the resistor and the ADC can be smaller than the power traces because not much current flows there.

I am not able to use two different net classes for the power trace and for the ADC traces. A soon as I change the class of the power trace, the sensors traces get the same net class and viceversa.

I have also tried to put a 0 ohm resistors along the sensor traces but this doesn't help neither.

Can anyone help me with this issue?

Thx

 

--

To view any images and attachments in this post, visit:

https://www.element14.com/community/message/274385

Fabrizio,

shorts.lbr can be found at

http://www.diymodules.org/eagle-show-library?type=usr&id=1012210749&part=shorts.lbr

HTH,

    - Chuck

On 4/17/19 13:54, Chuck Huber wrote:

Fabrizio,

 

Look in the shorts.lbr file.  It consists of two SMD pads that

overlap.  By putting a short in series with your smaller resistor, it

forms two different nets.  The net between the short and the resistor

could be assigned a different class allowing the narrower trace.  I

can send a shorts library to you.  Olin Lathrop is the original

author, and I've added a couple of my own.  Olin has published it on

the Internet, which is where I found it years ago.

 

My primary use of shorts is to connect different grounds together. 

i.e. I'll have a DGND, AGND, and HVGND representing grounds used in

different areas of a design (digital, analog, and high voltage).  In

the end, all these grounds need to be connected together.  I'll

connect DGND to GND through a short, then AGND to GND, and HVGND to

GND.  Just plain old GND will be routed back to the battery, or power

supply or whatever.

 

Of course, you could use the narrower trace just as you have it now. 

When you do the DRC, you can approve the error it generates and it'll

never bother you again... at least until you move it.

 

HTH,

    - Chuck

 

 

On 4/16/19 02:38, Fabrizio Boco wrote:

I have a trace which powers an external device and with a large size because it carries a relative high current (more than 1A).

Along this trace I have a small value resistor to monitor the flowing current.

The resistor is connected to an ADC to measure current. The traces between the resistor and the ADC can be smaller than the power traces because not much current flows there.

I am not able to use two different net classes for the power trace and for the ADC traces. A soon as I change the class of the power trace, the sensors traces get the same net class and viceversa.

I have also tried to put a 0 ohm resistors along the sensor traces but this doesn't help neither.

Can anyone help me with this issue?

Thx

 

--

To view any images and attachments in this post, visit:

https://www.element14.com/community/message/274385