This function in the 'Project' 'Check' menu tests whether in allocation of variables via the "AT" declaration overlaps have arisen at specific memory areas. For example, an overlap occurs when allocating the variables "var1 AT %QB21: INT" and "var2 AT %QD5: DWORD" because they both use byte 21. The output then appears as follows:

%QB21 is referenced by the following variables:

PLC_PRG (3): var1 AT %QB21

PLC_PRG (7): var2 AT %QD5

Results are displayed in the message window.