reads a region of Allen Bradley PLC Device memory.
The Allen Bradley Register Block Tag
reads a region of Allen Bradley PLC Device memory.
Note: This tag is only intended for use with file based PLC Devices. For example MicroLogix.
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 for information on how this field is formatted. Click the Browse button  to access the memory address editor.
|
| WordCount | UINT | 2.2 | The number of words to read. |
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 the data.
The Allen Bradley Register Block Tag supports these tag commands:
| Tag Command | Version | Description |
|---|---|---|
| Refresh | 2.2 | Requests an immediate read of the data from the PLC Device. |
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.
The Allen Bradley Register Block Tag builds on the features of these tag types:
To learn how activities are scheduled using Interval and Offset.
Allen Bradley PLC Data Address
To learn how to choose a data location in an Allen Bradley PLC Tag.
To learn about the I/O Analog Data Point Tag that can be associated with the Allen Bradley Register Block Tag.
To learn about the I/O Digital Data Point Tag that can be associated with the Allen Bradley Register Block Tag.
To learn about the I/O String Data Point Tag that can be associated with the Allen Bradley Register Block Tag.
To learn about the I/O Word Data Point Tag that can be associated with the Allen Bradley Register Block Tag.
I/O Double Word Data Point Tag
To learn about the I/O Double Word Data Point Tag that can be associated with the Allen Bradley Register Block Tag.
For an overview of the Allen Bradley Driver.
To learn about properties common to all Word Register Block Tags.
For the meaning of terms used in Fernhill SCADA.