Siemens v1.0 Wartungshandbuch PDF herunterladen (Seite 44)

Simple example

2.4 Create program

STEP 7 Basic V10.5

44 Getting Started, 12/2009, A5E02651459-01

PLC tag table

The PLC tag table contains the definition of the tags and constants that are valid for a PLC.

A PLC tag table is created automatically for each PLC created in the project.

The following table shows the meaning of the individual table columns of the "Tags" tab:

Column Description

Symbol you can click in order to move a tag into a network via a drag-and-drop

operation for use as an operand.

Name Unique name within the PLC that you assign to the tag.

Data type Data type that you specify for the tag.

Address Tag address.

Retentivity The values of retentive tags are retained even after the power supply is

switched off.

Monitor value Current data value in the PLC.

This column only appears if an online connection is available and you select

the "Monitoring" button.

Comment Comments to document the tags.

2.4.7 Defining and interconnecting PLC tags

Introduction

In the TIA Portal you have the options of directly creating tags when you create the user

program in the networks. The following steps show you how to define PLC tags and

interconnect the inserted LAD instructions with PLC tags. Depending on the tag values, the

LAD instructions are executed and thereby control the switching on and off of the machine.

Requirements

● The project has been created.

● The PLC is configured.

● The block "Main [OB1]" is open.

● The LAD instructions "Normally open contact", "Output coil" and "Negated coil" are

inserted in the first network of the organization block "Main [OB1]".

1 2 ... 39 40 41 42 43 44 45 46 47 48 49 ... 201 202

Keine Kommentare

Siemens v1.0 Wartungshandbuch Seite 44