Siemens SIMATIC S7-400H System Manual page 56

Installation of a CPU 41x–H
5.7 Structure and Functions of the Memory Cards
What memory card capacity to use?
The capacity of your memory card is determined by the scope of the user program.
Determining memory requirements using SIMATIC Manager
You can view the block lengths offline by selecting the "Properties - Block folder offline"
dialog box (Blocks > Object Properties > Blocks tab).
The offline view shows the following lengths:
● Size (sum of all blocks, without system data) in load memory of the PLC
● Size (sum of all blocks, without system data) in the RAM of the PLC
Block lengths on the engineering device (PG/PC) are not shown in the properties of the
block container.
Block lengths are shown in "byte" units.
The following values are shown in the block properties:
● Required local data volume: Length of local data in bytes
● MC7: Length of MC7 code in bytes
● Length of DB user data
● Length in load memory of the PLC
● Length in RAM of the PLC (only if hardware assignment is known.)
The views always show these block data, regardless whether it is located in the window of
an online view or of an offline view.
When a block container is opened and "View Details" is set, the project view always indicates
RAM requirements, regardless of whether the block container appears in the window of an
online or offline view.
You can add up the block lengths by selecting all relevant blocks. SIMATIC Manager outputs
the total length of the selected blocks in its status bar.
The view does not indicate the lengths of blocks (VATs, for example) which can not be
downloaded to the PLC.
Block lengths on the engineering system (PG/PC) are not shown in the Details view.
56
System Manual, 09/2007, A5E00267695-03
S7-400H