Siemens S7-1500 Function Manual page 77

Glossary
Instance data block (DB)
Each call of a function block in the STEP 7 user program is assigned a data block that is
automatically generated. Values of the input, output and in/out parameters, as well as local
block data, are stored in the instance data block.
IP address
The IP address is made up of four decimal numbers, each with a value range of 0 to 255.
The decimal numbers are separated by a dot (e.g. 192.162.0.0).
The IP address consists of the following:
● Address of the network
● Device address (PROFINET interface of the IO controller/IO devices)
Local data
This memory area accepts the temporary local data of a block for the duration of processing.
Memory reset
Procedure for setting the memories of the CPU to a defined initial state.
Operating states
Operating states describe the behavior of an individual CPU at any given point in time.
The CPUs of the SIMATIC standard systems feature the STOP, STARTUP and RUN
operating states.
The primary CPU of the redundant system S7-1500R/H has the operating states STOP,
STARTUP, RUN, RUN-Syncup and RUN-Redundant. The backup CPU has the operating
states STOP, SYNCUP and RUN-Redundant.
Optimized block access
Data blocks with optimized access have no fixed structure. In the declaration, the data
elements only receive a symbolic name, and no fixed address within the block. The elements
are automatically arranged in the block's available memory area in such a way that its
capacity is optimally exploited.
In these data blocks, you can only address tags symbolically. For example, you would
access the "FillState" tag in the "Data" DB as follows:
"Data".FillState
Optimized access offers the following advantages:
● The data is structured and saved in a manner that is optimal for the CPU used. This
allows you to increase CPU performance.
● Access errors, e.g. from the HMI, are not possible.
● You can selectively define individual tags as retentive.
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Structure and Use of the CPU Memory
Function Manual, 10/2018, A5E03461664-AC