Siemens NAN 67 Series Wartungshandbuch PDF herunterladen (Seite 56)

4-4

Ladder Logic (LAD) for S7-300 and S7-400

C79000-G7076-C504-02

4.2 Selecting a Method

When you create a DB in the SIMATIC Manager or in the LAD Editor, you

must select the method you want to use. You are prompted to select the

method in a dialog box.

New Data Block

Cancel

Create

eference:

OK Help

ata Block

Data Block Referencing a U

ser-Defined Data Type

Data Block Referencing a F

unction Block

Block: DB7

rogramming Tool: DB Editor

FB6

FB88

FB101

Figure 4-2 Selecting a Method and Assigning an FB/UDT

When creating a DB based on either a UDT or as an instance data block of an

FB, you make your selection in the list box that displays all existing UDTs

and FBs. The UDT or FB must already exist.

How you proceed from here depends on whether you are creating the DB by

assigning it or by creating a single declaration.

S Since the assigned UDT or FB defines the structure of the data block, you

have actually already created the new data block. The declaration table is

displayed on your screen, but no further changes can be made to it.

S If you are defining the structure of a shared data block, you must now edit

the declaration table, declaring the variable names and data type and, if

you require, the initial value and comment (see Section 4.3).

Procedure

How to Proceed

Creating Data Blocks and User-Defined Data Types

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