Hi i am new user here and working on PLCs from last 10 years. As per my knowledge the compiler needs a device memory area which it can use to assign local labels at compilation time. You can define these in the Tool menu (Device/Label Automatic-Assign Setting). For example, say you use a local label of datatype Bit somewhere in your code. The compiler needs to assign an address to this local bit at compilation time before transferring it to the plc. In my example, the compiler takes a device address out of the device memory area that you have reserved for bits. That could be an M-range or a B-range or whatever depending on what you have defined.
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