# Altium - Do Schematic Variables Exists?

In Altium Designer (v.16.0), I would like to assign several resistors with the value "R", and being able to change them only by assigning the value of R to e.g. 10k, at some place of the application.

I've been unable to seek this on internet nor in the tutorials, i always got with the Parameter concept, which are the standards values specifying the components. I am thinking on general values, like global variables, or local variables per Schematic, so you can use them as in a design stage, eventually using operations such as R/2 or 2R, etc.

• You can assign all of these resistors to a Class, then use Find Similar Objects to select them all and change their properties all at once. – The Photon Feb 7 '18 at 5:27
• If you are ok with scripting in Delphi or VB you can create a post processing script that will put this effect in your BOM, not your schematic though. Essentially you would parse each components Value field that you populate with R*x then apply your scalar to the same field. I cannot think of a way for altium to do this for you in the schematic apart from variants, but that's still not quite what you are asking for. – Luke Gary Feb 7 '18 at 10:49
• I am actually wanting to do this for the simulation stage. The running VB could change the value of components at my command. It is an interesting alternative...... – Brethlosze Feb 7 '18 at 13:21

## 1 Answer

I do not believe Altium supports this kind of parameterized behavior. As Photon suggested, you can add them to a class or take some other kind of action that will allow you to select them, or use the assembly variant functionality to swap between different value configurations-- but you'll have to assign the part changes individually in each variant.

If you have the components in a database, you could change the value in the database and update the components, but that is probably going to be messy.

• Is it possible to define such variables as Spice code into the AdvancedSim Generated Netlists?. Because those files are generated, i think it is not possible to introduce Spice script into there... – Brethlosze Apr 16 '18 at 19:47
• @hyprfrcb I don't know the answer to that. – Daniel Apr 17 '18 at 19:52
• I found it is possible to define parameters, just like the .PARAM SPICE command, which indeed works exactly like that. It is found under Simulation>Global Parameters. – Brethlosze Apr 20 '18 at 17:38