Tag Archives: schematic capture

Parameters in Altium Designer

I use Altium Designer a lot for schematic capture and PCB layout: drawing electronic circuits, in other words. It has a handy feature called ‘Parameters’ which should make it easy to add a piece of data, for example a version number or the author’s name, to a project and have it appear on all of the documents which form part of that project. I’ve always had trouble getting it to work, but I’ve finally cracked it and I’m writing down my findings here so that I don’t forget them. Other people may find it useful too.


1. It’s possible to set parameters on a project and then refer to them in documents, but if there is a parameter in the document with the same name, it will hide the project parameter.

For example, all schematic documents have a ‘Revision’ parameter by default. If I set a ‘Revision’ parameter for the project, it won’t appear in any of the documents because the document ‘Revision’ parameter hides it. If I choose a new name which isn’t already used in the documents, like ‘ProjectRevision’, it does appear in the document.

2. In schematic documents, parameters are referred to using the equal sign:


In PCB documents, they’re referred to using a dot:


It’s bonkers, but it’s true.

Here’s my recipe for getting a version number to appear on both schematic documents and the PCB layout.

  1. Set your version number on the project using Project -> Project Options -> Parameters. Call it something which isn’t one of the default document parameters. I use ProjectRevision.
  2. In schematic sheets, use =ProjectRevision in text strings to call up the version number.
  3. In PCB sheets, use .ProjectRevision in text strings to show the version number.
  4. Make sure ‘Convert Special Strings’ is switched on in both schematic and PCB editors otherwise you won’t see the version number.

For the schematic editor, select Tools -> Preferences -> Schematic -> Graphical Editing and make sure ‘Convert Special Strings’ is ticked.

For the PCB editor, select Design -> Board Layers and Colours -> View Options and make sure ‘Convert Special Strings’ is ticked.

That’s it. Using parameters has made managing my Altium projects quicker and easier.