Allen Bradley Register Block Tag

Introduction

The Allen Bradley Register Block Tag Register Block Tag Icon specifies a region of Allen Bradley PLC memory and how often to read the data from the PLC.

Configuration Properties

The Allen Bradley Register Block Tag supports the configuration properties of the Word Register Block Tag plus these additional configuration properties:

Property Type Version Description
ScanInterval TIME 2.2 The interval between each scan. See Interval and Offset for information on how Intervals and Offsets define the time of activities.
ScanOffset TIME 2.2 The offset added to the ScanInterval to get the actual scan time. See Interval and Offset for information on how Intervals and Offsets define the time of activities.
Device Reference 2.2 The Allen Bradley PLC Tag where the register block is located.
DataAddress STRING[16] 2.2 The data address of the first word of the register block.
See Allen Bradley PLC Data Address Format for information on how this field is formatted. Click the Browse button Browse button to access the memory address editor.
WordCount UINT 2.2 The number of words to read.

WordCount Property

The Allen Bradley protocol defines maximum limits for the number of words that can be read in a single read request. When the WordCount property exceeds these limits, the driver will use multiple read requests to read all of the data.

Tag Commands

The Allen Bradley Register Block Tag supports these tag commands:

Tag CommandVersionDescription
Refresh 2.2 Requests an immediate read of the data from the PLC.

Note: Event triggered data reads (from the Refresh tag command) and periodic data reads (defined by the ScanInterval property) are independent. You can use the Refresh tag command, or the ScanInterval property, or both to determine when the data is read from the PLC.

Relationships to Other Tag Types

The Allen Bradley Register Block Tag builds on the features of these tag types:

Further Information

Interval and Offset

To learn how activities are scheduled using Interval and Offset.

Allen Bradley PLC Data Address Format

To learn about how to specify a data location in an Allen Bradley PLC Tag.

IO Analog Data Tag

To learn about the IO Analog Data Tag that can be associated with the Allen Bradley Register Block Tag.

IO Digital Data Tag

To learn about the IO Digital Data Tag that can be associated with the Allen Bradley Register Block Tag.

IO String Data Tag

To learn about the IO String Data Tag that can be associated with the Allen Bradley Register Block Tag.

IO Word Data Tag

To learn about the IO Word Data Tag that can be associated with the Allen Bradley Register Block Tag.

IO Double Word Data Tag

To learn about the IO Double Word Data Tag that can be associated with the Allen Bradley Register Block Tag.

Allen Bradley Driver

For an overview of the Allen Bradley Driver.

Word Register Block Tag

To learn about properties common to all Word Register Block Tags.

Glossary

For the meaning of terms used in Fernhill SCADA.