When modifying the schematic, there may be changes that you want export to an existing PCB layout. This process is called forward annotation. Similarly, when modifying the PCB layout, there may be changes that you want to export to the schematic. This process is called backward annotation.
Both forward and backward annotation consist of the following steps:
?Compare the netlists for the two design versions
?Create the ECO (engineering change notice) file that describes the changes needed to update the original design to match the new design with changes
?Import the ECO file into the original design
Note: You cannot perform forward and backward annotation between PowerLogic and BlazeRouter because BlazeRouter does not import or export ECO files.
Forward Annotation
If PowerLogic and PowerPCB are on the same computer, you can perform forward annotation using ECO To PCB on the Design tab of the
OLE PowerPCB Connection dialog box. ECO To PCB compares the PowerLogic schematic in memory to the current PowerPCB design, and then automatically updates the PowerPCB design with the resulting ECO file.
If PowerLogic and PowerPCB are not on the same computer, you can use the Forward ECO to PCB dialog box to compare the design versions and create the ECO file, and then import the ECO file into PowerPCB. For information, see the "Importing Files" topic in PowerPCB Help.
Backward Annotation
If PowerLogic and PowerPCB are on the same computer, you can perform backward annotation using ECO From PCB on the Design tab of the OLE PowerPCB Connection dialog box. ECO From PCB compares the PowerLogic schematic in memory to the current PowerPCB design, and then automatically updates the PowerLogic design with the resulting ECO file.
If PowerLogic and PowerPCB are not on the same computer, in PowerLogic create a PADS-format ASCII netlist file (.asc), in PowerPCB compare the design to the schematic netlist file (.asc), and then in PowerLogic import the ECO file. For information, see Creating a Netlist, the "Comparing and Updating Designs" topic in PowerPCB Help and Backward Annotate from PCB.
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