Back annotation from CAD into Text documents?

Hello Folks,

Is there a way to back annotate a text from a schematic or netlist output or other means?

I write my docs while doing the schematic and can only use the designators as they pop up when parts are placed. However, when doing the renumbering so R1, C1, Q1 and so on start at the upper left all designators change. Then it's hand editing the text.

When the layouters are done they send back annotation again. Then the text needs to be edited. Again. Any hope?

Regards, Joerg

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Joerg
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Hi Joerg, I'm not quite following you. Examples?

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Jim Thompson

Why don't you just write your documentation _after_ you have a final schematic?

I think OrCAD has management tools built-in??

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Jim Thompson

I use Macro Express. One of many macros I've written adds a time and date stamp. And, anytime I make a change, I simply "Save As" to keep track of the REV's. PSpice also has "Checkpoints", storing intermediate steps in building a schematic, but I always forget to use it ;-)

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Hello Jim,

When I start a design I place parts as I go. Let's say, the switcher first just to get the ugly stuff out of the way. Then maybe an amp in the lower left, then a digital section in the upper right.

Now the part designators will be nearly random. R1 is somewhere in the middle because I had place it first, C1 somewhere else because that was my first cap. At the same time I begin writing the module spec, using these designators as Cadsoft Eagle assigns them. It assigns them in a way that the number increases by one every time you place, regardless where on the board you place. This was the same with OrCad and others.

To make a schematic more readable to the client's engineers it is then customary to run a "re-number". Now R1 is in the upper left corner, so is C1, Q1 and so on. Then the designator numbers increase towards the lower right. IOW what used to be R1 is now R83. The dilemma: Now none of the designators in my module spec are correct. They all need to be changed by hand.

Ok, off to layout. Usually done by third parties just like you have yours done outside. If it is a large board it is again customary to start C1, R1, Q1 and so on in the upper left of the physical PCB. That may not at all be the circuitry that is in the upper left of the schematic, meaning the resistor I had changed from R1 to R83 in the spec now becomes R37. So here I go again, having to change all the numbers in the module spec for the second time.

Regards, Joerg

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Joerg

Hello Jim,

Writing in parallel helps a lot in making sure it is complete and all thoughts are in there. The thoughts might not all stay but I won't forget any. Too often I have seen engineers design a complicated board the size of a baking pan and then scratch their head later. What was I thinking? Why did I do that over here? What's L3 doing in there?

I grew up in med electronics and we are all used to this. In the med world parallel documenting is actually regulated into the process, at least for sensitive gear. You have to create a design history file. And when the FDA inspector cometh that file better be there.

Mine didn't but it's old. I am not aware of anything in there until version 9 that would do document back annotation.

BTW, Cadsoft Eagle does a nice job in design history. I print every intermediate step and stamp the date and time on it. But this CAD program also keeps these files as running backups. So I could always show the version I had, say, Monday last week.

Regards, Joerg

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Joerg

Hello Jim,

Writing in parallel helps a lot in making sure it is complete and all thoughts are in there. The thoughts might not all stay but I won't forget any. Too often I have seen engineers design a complicated board the size of a baking pan and then scratch their head later. What was I thinking? Why did I do that over here? What's L3 doing in there?

I grew up in med electronics and we are all used to this. In the med world parallel documenting is actually regulated into the process, at least for sensitive gear. You have to create a design history file. And when the FDA inspector cometh that file better be there.

BTW, when a client's engineer crashed his motorcycle the fact that he kept his spec current saved their bacon. I could jump right in.

Mine didn't but it's old. I am not aware of anything in there until version 9 that would do document back annotation.

BTW, Cadsoft Eagle does a nice job in design history. I print every intermediate step and stamp the date and time on it. But this CAD program also keeps these files as running backups. So I could always show the version I had, say, Monday last week.

Regards, Joerg

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Joerg

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