I am drawing a schematics in Altium Designer and faced this function when I double click on the components. I need to know when there is a component with different parts, ex: 4 parts. I have to assign the first part as Part 1/4 and the second part as 2/4 ... etc
Do I need to Enable the Locked function or not ? And what does it mean ?
In short
Parts inside component
A Component may have more than one parts, for ex: LM324 has 4 op-amps inside. With the part option, you select which one to use. Altium will create netlist for the pins with the part you have selected.
Part locked
Now, when you annotate the schematic, Altium not only changes the component names with ? (for ex U?), but also the parts. This may cause trouble in PCB because it effects witch pins of the part is connected to the rest of the circuit. If you select "part locked", Altium will keep all locked parts with your selections. For ex: A component with locked enable, lets say U?/part2 will not change to U1/part1 when you annotate schematics. It will be something like Uxx/part2 always.
Expanding on Viral - Embedded hardware's answer. The locked function also makes the component non-selectable which means a single click would not select the component. This feature comes in handy when you have overlapping components.
Locked function when enabled, it means components value,name,annotate cannot be modified. This function is given to prevent the accidentally changing of the any of the components in schematic.
