Essenital settings in S7 PLC
The following settings are needed for S7-1200 and S7-1500
1. Change the CPU protection level:
a. Open your PLC project in TIA Portal.
b. Select the PLC in the project tree and choose the Properties command.
c. Choose "Full Access".
2. Change DBs settings:
a. Open the "Program Blocks" folder in the project navigation.
b. Right-click the block the access type of which you want to change.
c. Select the "Properties..." item in the pop-up menu.
d. In the "Attributes" tab, Uncheck "Optimized block access".
For more information, review this document from Siemens website.