On 10:50 AM 29/10/2001 +0000, Andrew Ircha said:
>Forgive me if this subject has been done to death. If so, please offer
>me some pointer to a repository.
>I'd like to change the designators on my PCB to make it easier to find
>components on the board. There's been some talk about a synchroniser,
>but I've found the discussion confusing because there's nothing I can
>immediately see is called a synchroniser under the Protel menus, and
>because I've not joined the threads from the beginning.
>Presumably there is more than one way to do this, and judging from
>Protel's track record one of these methods is more reliable than the
>I'd like to change the designators so they read in some kind of
>ascending order from say, left to right across the board.
>Any advice gratefully received.

1) The synchronizer is a pair of processes that you can use to exchange 
info between Sch and PCB.  It extends the facilities of the old netlist 
load (which still exists).  It appears in your Sch menu as Design|Update 
PCB, and in PCB as Design|Update Schematic.  It works by associating a 
hidden handle with each Schematic component and PCB footprint.  These 
hidden handles are then used to match sch component with a PCB component - 
regardless of changes to the designators etc.  When you first try to update 
a PCB from a Sch you will be  prompted to match sch components by PCB 
component - create the initial match.  You have the opportunity to change 
the match and to manually match components which do not have then same 
designator.  The system automatically initially offers a match based on 
designators.  If you use the Update PCB  process to load in components into 
a PCB then the match is obviously made automatically.

2) Before re-annotating in the PCB it is strongly recommended that you set 
up the hidden handle match by running the synch - this will save you a lot 
of work in manually matching.  Then you can safely re-annotate as many 
times as you like before back annotating the Sch (using the Design|Update 
Schematic process).  When back annotating the sch it is useful to know that 
footprint and comment changes are transferred back to the sch but it does 
not transfer back any netlist info (i.e. changes to pin connections). I use 
the update sch to transfer all the bottom side (wave) footprints to the sch 
to ensure complete match - that is when I design the sch everything has a 
reflow footprint, as the PCB design progresses it is sometimes necessary to 
flip a component(s) to the bottom side.  On a wave/reflow PCB this may 
entail using different footprints for top and bottom, the Update Sch 
process helps keep everything in match. I use the synchroniser exclusively 
(and have since it was introduced) to do the initial load of the footprints 
into the PCB.  In the old days of netlists and no hidden handles, it was 
necessary to immediately run the back-annotate command when a PCB 
re-annotate was done to ensure the all important was-is file was 
current.  This was a pain.

3) as others have mentioned there is a re-annotate process in PCB that can 
do the re-numbering.  There have been some reports on this list of some 
problems with the designator ordering, I think.  I can't recall the details.

4) when you run the synch you may find that you see a whole lot of hatched 
rectangles on your PCB.  These are "rooms" and can be deleted if you do not 
wish to use the rooms feature.

Bottom line - you will get an easier result by making sure your Sch and PCB 
are matched through the synch before doing your PCB re-annotate.  Do this 
by running Design|Update PCB.  It is very instructive to check the Preview 
changes button so you can see (and edit/delete) the macros that will be run 
over the PCB.  Also, think carefully about which options you want to 
include.  Delete Components (removing footprints not in the Sch design) may 
not be what you want if you have mechanical parts that you have not 
exploded - they will get removed.  The assign net to connected copper 
option can really slow down the update.

There is more that could be said but that is enough from me I think,
Ian Wilson

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