Siemens SIMATIC S5-115U, User Manual

Page: 184 / 676

Introduction to STEP 5 S5-115U Manual
Block Header
In contrast to other types of blocks, function blocks have other organization information in
addition to the block header.
Its memory requirements consist of the following:
•
block description as for other blocks (five words)
• block name (five words)
• block parameter for parameter assignment (three words per parameter).
Creating a Function Block
In contrast to other blocks, parameters can be assigned to FBs. To assign parameters, you must
program the following block parameter information:
•
Name of the block parameter (formal operands)
Each formal operand receives a name (declaration "DECL"). The name can contain up to four
characters and must begin with an alpha character. You can program up to 40 block para-
meters per function block.
• Block Parameter Type
You can enter the following parameter types:
- I
input parameters
- Q output parameters
- D data
- B blocks
- T timers
- C counters
Output parameters are represented to the right of the function symbol in graphics representation
(CSF). The other parameters are to the left.
• Block Parameter Data Type
You can specify the following data types:
- BI
for operands with bit address
- BY for operands with byte address
- W for operands with word address
- K for constants
7-12
EWA 4NEB 811 6130-02b