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SCE_EN_040-020_R1209_Startup Programming in High-Level Languages with S7-SCL and SIMATIC S7-300
4.4 Interface of the block calculate_tankcontent [FC140]
The interface of the block must be declared before the program can be written. In the interface
declaration, the local tags known only in this block are defined.
The tags or interface parameters are divided into two groups:
 Block parameters that form the block interface for the call in the program.
Type
Designation
Function
Available in
Input parameters
Input
Parameters whose values are
read by the block.
Functions, function blocks, and some
types of organization blocks
Output parameters
Output /
Return
Parameters whose values are
written by the block.
Functions and function blocks
In/out parameters
InOut
A parameter whose value is read
by the block when it is called and
is written back by the block to
the same parameter after it is
processed.
Functions and function blocks
 Local data that is used for saving intermediate results.
Type
Designation
Function
Available in
Temporary local data
Temp
Tags that are used to store
temporary intermediate results.
Temporary local data is retained
for one cycle only.
Functions, function blocks, and
organization blocks
Static local data
Static
Tags that are used for saving
static intermediate results in the
instance data block. Static data
is retained until it is overwritten,
which may be after several
cycles.
Function blocks