Rockwell-automation Logix5000 Controllers I/O and Tag Data Programming Manuale Utente Scaricare il pdf (Pagina 55)

Chapter 3

Force I/O

Use a force to override data that your logic either uses or produces. For example,

use forces to:

• Test and debug your logic.

• Check wiring to an output device.

• Temporarily keep your process functioning when an input device has failed.

Use forces only as a temporary measure. They are not intended to be a permanent

part of your application.

When you use forces, take these precautions.

ATTENTION: Forcing can cause unexpected machine motion that could injure personnel. Before you use a force,

determine how the force affects your machine or process and keep personnel away from the machine area.

− Enabling I/O forces causes input, output, produced, or consumed values to change.

− Enabling SFC forces causes your machine or process to go to a different state or phase.

− Removing forces may still leave forces in the enabled state.

− If forces are enabled and you install a force, the new force immediately takes effect.

Enable forces

You must enable forces for a force to take effect. You can only enable and disable

forces at the controller level.

• You can enable I/O forces and SFC forces separately or at the same time.

• You cannot enable or disable forces for a specific module, tag collection, or

tag element.

Important: If you download a project that has forces enabled, the application prompts you to enable or disable forces

after the download completes.

When forces are in effect (enabled), a appears next to the forced element.

Introduction

Precautions

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Rockwell-automation Logix5000 Controllers I/O and Tag Data Programming Manuale Utente Pagina 55