You are here

Differences between Symbol and Comp in the Allegro PCB Editor

Problem

What is the difference between "Symbol" and "Comp" in the Find filter in Allegro PCB Editor?

Why is the preselect mode not available for "Comps"?


Solution

"Symbols" are any component placed on the board, whether placed using a netlist or placed directly from a library (with no netlist associated). If you use Show Element to display information about a symbol that is associated with a netlist, you will see information about the package symbol (.dra), such as the symbol name and attached text. You will not see any information that is associated with a netlist (net names, pin numbers, pin type, and so on).

"Comps" are components that are associated with the logic (netlist). If you use Show Element to display information on "Comps", you will see more design-specific data. This includes any properties (SIGNAL_MODEL, ROOM, and so on) associated with the component (net names, pin numbers, pin type, class, and so on).

Why is the preselect mode not available for "Comps"?

In the preselect mode, an object/command selection is application mode dependent. Application modes are “tuned” for the typical operations that are executed while in that mode. Because manipulating properties on components is not a typical operation, when the preselect mode is active, Property Edit is not available for "Comps". Any command, included in the current Allegro PCB Editor product tier in use, is available from the appropriate Allegro PCB Editor menu or from the Allegro PCB Editor command line.

This “legacy” editing mode may be used, instead of the “pre-select” mode, when less common operations are required. To manipulate the properties of a component instance, use this legacy “post select” mode.

  • Select Edit > Properties from the Allegro PCB Editor menu. Ensure that both "Comps" and "Symbols" are selected in the Find filter.
  • Click on a visible symbol. "Comp" is selected because the component object is the parent object of the symbol object. The properties of that "Comp" are displayed in the Show Properties form and are editable in the Edit Properties dialog.
  • The Allegro PCB Editor console, if visible, reports that “Component: U1 has been selected.”