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3-23

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

C79000-G7076-C504-02

3.11 Editing Addresses and Parameters

The Block Editor uses the character string ??:? as placeholders for addresses

and parameters when you insert a Ladder instruction. All addresses and

parameters must be completed correctly for an executable code section. The

exceptions to this are FBs and SFBs or timer and counter boxes that do not

need to have all parameters assigned. Addresses and parameters can be

entered in absolute or symbolic form.

To edit an address or a parameter, open the corresponding text box by

clicking the placeholders ??.?. When you have completed your entry its

syntax is checked. If errors are found, the address or parameter is displayed

in red and an error message appears in the status bar. If the syntax is correct,

the next text box which has not yet been edited is opened.

m1.6

??.?

Step 1.

Step 2.

M1.6

Step 3.

Figure 3-14 Entering Addresses for Ladder Instructions

As you become familiar with the editing tools in Ladder, you can enter all

elements in a network first, and later assign the address or a parameter, to

each element.

Because they are marked in red, errors are easy to recognize. To allow you to

navigate more easily to errors located outside the currently visible screen

section, the Editor has two search functions: Edit

Go To...

Error/Next Error which can also be activated from buttons in the toolbar.

The error search extends beyond the network. This means errors are found

throughout the entire code section and not just within the network or

currently visible section of the program. If you activate the status bar with

the menu command View

Status Bar, information about the errors will be

displayed in the status bar.

You can correct errors and make changes in the overwrite mode (see

Section 3.13).

Uses

Procedure

Debugging

Creating Logic Blocks

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Siemens NAN 67 Series Manual de servicio Pagina 47