Aligning D-Sub Pins

On Thu, 31 Mar 2011, Alex wrote to us saying :

>I am trying to precisely align a d-sub 25 connector on a PCB according to a

>technical drawing provided by a company. In the drawing the part is aligned

>based on the top left pin in the d-sub assembly.

 

My problem is that the coordinate locus for the dsub connector in EAGLE is

>in the center of the part, with dimensions to the top left pin arbitrarily

>defined. I am attempting to match/ move the entire pin assembly such that

>the top left pin is the coordinate locus for the entire part.

>Does anyone have any tips?

Yes: get the "company" to provide a more useful drawing. The exact size

of a D-sub connector is quite well defined, but nobody really cares

where the corner pin is. The people designing the case need the outline,

and the PCB designer needs all the pins. The standard way to specify the

position is by the centre, just like Eagle does.

Alternatively, get a data sheet of D-sub connectors and it will tell you

what offsets you need to add to the supplied drawing to find the centre.

Then locate the standard library part on your PCB at that location.

--

Rob Pearce                       http://www.bdt-home.demon.co.uk

The contents of     | All power corrupts, but we need electricity.

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purely my opinion.  |

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word.               |

On 03/31/2011 04:44 PM, Alex wrote:

Hello!

 

I am trying to precisely align a d-sub 25 connector on a PCB according to a

technical drawing provided by a company. In the drawing the part is aligned

based on the top left pin in the d-sub assembly.

Alex,

Try this:

Open the library from which you added the connector to the schematic and

examine the package.  Show the properties of pin 1 and note the

coordinates.  These are relative to the center of the part.

On the PCB, add or subtract these coordinates to those that are provided

by the company, and do a precise move.  By "precise", I mean type

something like this in the command line text box:

    move J3 (newXCoord newYCoord)

Of course, replace J3 with whatever name your connector has.

Enjoy,

    - Chuck

On 3/31/2011 4:44 PM, Alex wrote:

Hello!

 

I am trying to precisely align a d-sub 25 connector on a PCB according to a

technical drawing provided by a company. In the drawing the part is aligned

based on the top left pin in the d-sub assembly.

 

  My problem is that the coordinate locus for the dsub connector in EAGLE is

in the center of the part, with dimensions to the top left pin arbitrarily

defined. I am attempting to match/ move the entire pin assembly such that

the top left pin is the coordinate locus for the entire part.

 

Does anyone have any tips?

 

Please let me know if this needs to be clarified.

 

Thanks,

Alex

I think you need to use the library editor to examine the

package/footprint for the D-sub connector.   By using the info command

you can get the exact coordinates for the top left pad/hole in question

relative to the part origin.    Once you know the coordinates of the top

left pin relative to the package/part origin a little math will tell you

where you need to place the part on the board to get the top left pin in

the right spot.

Jim

Alex wrote:

Hello!

 

I am trying to precisely align a d-sub 25 connector on a PCB

according to a technical drawing provided by a company. In the

drawing the part is aligned based on the top left pin in the d-sub

assembly.

 

My problem is that the coordinate locus for the dsub connector in

EAGLE is in the center of the part, with dimensions to the top left

pin arbitrarily defined. I am attempting to match/ move the entire

pin assembly such that the top left pin is the coordinate locus for

the entire part.

A couple of hints.

The responders have all suggested using the current library part, finding

the offset of pin1 relative to the part's origin and offsetting the part by

this much so the part ends up with the pin1 in the correct place.

Verify the placement using MARK. You can measure back to the point the

company provided as the reference point.

Alternatively you make a device variant that has the origin on pin1

Create a copy of the library package. GROUP and move all the package content

so pin1 ends up at the origin point. This a new package which you use to

create a variant within the device.

HTH

Warren

Warren, this is exactly what I want to do. How can I group and move the

entire pinset such that the top left pin is at exactly the origin?

For being a precision tool, EAGLE sure makes it difficult to decide exactly

how to place that origin...

--

Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

On 4/5/2011 3:27 PM, Alex wrote:

Warren, this is exactly what I want to do. How can I group and move the

entire pinset such that the top left pin is at exactly the origin?

 

For being a precision tool, EAGLE sure makes it difficult to decide exactly

how to place that origin...

I would:

   grid finest

   show all layers

   group all elements of drawing

     click move button

     right click the new origin pin

     type (0 0) into command line and hit enter.

fix layers

grid last

This almost worked, it was off by about 1.5mils from the origin of the

part. You have to be sure right click at the exact center of the new

origin pin, by zooming, to get it better.

Alex wrote:

Warren, this is exactly what I want to do. How can I group and move

the entire pinset such that the top left pin is at exactly the origin?

 

For being a precision tool, EAGLE sure makes it difficult to decide

exactly how to place that origin...

The origin of the part is established when the library part is created. It

cannot be done/changed in the board editor.

You can only move the origin if you modify the library part.

Normally for this use you would not modify the existing part package but

create another package, initially copied from the current package, and use

that to create a device variant, the package of which has the origin on pad

1.

If you are struggling with the process to perform what I have said I

susupect  you have not spent the time to read the manual and worked through

the tutorials for creating library parts. If you are to be successful with

Eagle, part/library creation is a 'must have' skill.

If you wish to avoid doing this then use the method proposed by others to

get the package/pad located as desired and then confirm it is placed

corrrectly relative to your reference point. You will need to use similar

techniques to do it this way  as you need when doing it the library way.

If you want a very easy  'eye-ball' method I would do it as follows:

Place a MARK, using the command line, at the position you want the pad. If

you have done it correctly this willl be the exact position you need to move

the pad (the whole DB9) to.

Then set the ALT grid to finest.

Next grab the DB9 and with the ALT key depressed, so the Alt grid is active,

move the DB9 until the pad is over the MARK cross. You should continue to

increase the magnification as you get closer and closer which you do with

the scroll of the mouse.

HTH

Warren

"Alex" <omegacore@gmail.com> wrote in message

news:ing4vv$9rk$1@cheetah.cadsoft.de...

Warren, this is exactly what I want to do. How can I group and move the

entire pinset such that the top left pin is at exactly the origin?

 

For being a precision tool, EAGLE sure makes it difficult to decide

exactly

how to place that origin...

Its not hard. You just need to learn the basics.

Here is a general way for any kind of grid:

-Find the coord of the new origin (x y)

-Make sure all layers are visible

-Type the command "group all"

-Type the command "move (>cx y) (0 0)" where x and y is the coord of the new

origin you want.

You're done!

The '>' simulates a right mouse button click, and the 'c' simulates ctrl

button. This is more convenient to do with a command than the mouse, cause

the mouse resolution isn't good enough, and the mouse pointer coordinates

may be affected by the grid.

On Wed, 6 Apr 2011, Morten Leikvoll wrote to us saying :

>This is more convenient to do with a command than the mouse, cause

>the mouse resolution isn't good enough, and the mouse pointer coordinates

>may be affected by the grid.

And because point-and-click type interfaces are fundamentally the wrong

tool for high precision. That's why we need grids in the first place. If

you want to be very precise about where to put things, you need to be

precise in what you instruct the tool to do. For that you need a command

line.

--

Rob Pearce                       http://www.bdt-home.demon.co.uk

The contents of     | All power corrupts, but we need electricity.

this message are    |

purely my opinion.  |

Don't believe a     |

word.               |

Morten Leikvoll wrote:

>[...]

>-Type the command "group all"

>-Type the command "move (>cx y) (0 0)" where x and y is the coord of the new

>origin you want.

the 'c' in 'move (>cx y) ...' is not neccessary - but won't hurt

either

--

Lorenz