Siemens Memory Specifications download pdf (Page 13)

2 S7-1200/1500 Innovations

2.6 Optimized blocks

Programming Guideline for S7-1200/1500

V1.2, Entry ID: 81318674

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Recommendation

 Always only use optimized blocks.

– They do not require absolute addressing and can always be addressed

with symbolic data (object related). Indirect addressing is also possible with

symbolic data (see chapter 3.6.2 ARRAY data type and indirect field

accesses).

– The processing of optimized blocks in the controller is much faster than

with standard blocks.

 Avoid the copying/assigning of data between optimized and non-optimized

blocks. The required conversion between source and destination format

requires high processing time.

Example: Setting optimized block access

The optimized block accesses for all newly created blocks for S7-1200/1500 is

enabled by default. Block access can be set for OBs, FBs and global DBs. For

instance DBs, the setting depends on the respective FB.

The block access is not reset automatically when a block is migrated from a

S7-300/400 controller to a S7-1200/1500. You can change the block access later

on to “optimized block access”. You need to recompile the program after changing

the block access. If you change the FBs to “optimized block access”, the assigned

instance data blocks are automatically updated.

Follow the instructions below, in order to set the optimized block access.

Table 2-4: Setting optimized block access

Step Instruction

1. Click the “Maximizes/minimizes the Overview” button in the project navigation.

2. Navigate to “Program blocks“.

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 73 74

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Siemens Memory Specifications Page 13