Siemens NAN 67 Series Manual de servicio descargar pdf (Pagina 34)

3-10

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

C79000-G7076-C504-02

3.5 Declaring Multiple Instances

A multiple instance results from declaring a static variable of the same data

type as a function block (FB). In the code section, the instance is called as a

Ladder element.

For more detailed information about multiple instances, refer to the

Programming Manual /234/. Part 2 of this manual explains the syntax for

calling a multiple instance.

Keep to the following rules when declaring multiple instances:

S Declaring multiple instances is only possible in function blocks

S Function blocks within which a multiple instance has been declared must

also have an associated instance DB.

S A multiple instance can only be declared as a static variable (declaration

type “stat”).

To declare a multiple instance, you enter the variable name in the “Symbol”

column after the declaration type “stat”. Under data type, you enter the

function block. This can be done either by entering the absolute name of the

FB or a symbolic name. You can also add an optional comment.

TRAFFIC\...\FB60-<Offline>

varin

varout

varinout

tempo

BYTE

REAL

B#16#0

out

in_out

stat

temp

0.0

2.0

4.0

0.0

locinst

local instance

FB6

Decl. Symbol Data TypeInitial Value CommentAddress

Figure 3-5 Declaration of Multiple Instances (Example)

Multiple Instances

Rules

Inputting Multiple

Instances

Creating Logic Blocks

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 317 318

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