Product Overview

The Allen-Bradley 1784-SD2 is a 2 GB Secure Digital (SD) memory card used with compatible ControlLogix and GuardLogix programmable automation controllers. It provides nonvolatile storage for controller user programs, tag data, and diagnostic information.

The card is particularly associated with the ControlLogix 5570 and 5580 controller generations. It is installed in the designated SD card socket on the processor, allowing the controller to retain application information independently of its normal operating power.

One important application of the 1784-SD2 is controller program backup and recovery. Engineers can use the supported Logix programming environment to save controller information to nonvolatile memory and restore stored data when required. Compatible controllers can also be configured to load an application from the memory card during startup.

The 1784-SD2 also has a diagnostic function. Rockwell Automation recommends leaving the SD card installed in compatible ControlLogix 5580 and GuardLogix 5580 controllers so that diagnostic information can be written to the card when a controller fault occurs.

Unlike the CompactFlash memory cards used by earlier ControlLogix 5560 controllers, the 1784-SD2 uses Secure Digital technology. Its application therefore depends on the processor generation and supported memory-card configuration.

For industrial maintenance teams, this card is useful for controller backup, application restoration, diagnostic data retention, and long-term management of compatible Logix-based automation systems.

Technical Specifications

Product Features

1. 2 GB Storage Capacity

The 1784-SD2 provides 2 GB of Secure Digital storage for controller applications, tag data, and associated information. This capacity supports nonvolatile storage requirements in compatible Logix controller installations.

2. Nonvolatile Data Retention

Stored information remains available without continuous controller power. This allows engineers to maintain a separate copy of important application data for supported backup and recovery operations.

3. ControlLogix 5570 Compatibility

The card supports applicable ControlLogix 5570 controller configurations. It can be used as an optional memory card for compatible processors in this generation.

4. ControlLogix 5580 Integration

The 1784-SD2 is supplied as the installed memory card in standard ControlLogix 5580 controller configurations. It provides the storage location for controller data and diagnostic information.

5. GuardLogix Controller Support

The card is also associated with compatible GuardLogix 5580 controllers. It supports the nonvolatile memory functions available through the corresponding safety controller architecture.

6. Program Backup and Restoration

The memory card allows supported controller applications to be saved and restored through the Logix programming environment. This helps maintenance teams recover application information during servicing.

7. Diagnostic Data Storage

Compatible controllers can write diagnostic information to the installed SD card when certain faults occur. This information can assist Rockwell Automation in investigating controller problems.

8. Configurable Startup Loading

Supported controller configurations allow applications stored in nonvolatile memory to be loaded during powerup. This provides an additional recovery option for applications requiring predefined startup behavior.

Working Principle

The 1784-SD2 operates as a removable nonvolatile memory device within a compatible Logix controller.

During normal operation, the controller executes its application program using its internal processing resources. The SD card provides a separate storage location for retaining the user program, tag data, and other supported information.

When an engineer initiates a save operation through the programming software, the controller transfers the selected information to the installed memory card. The saved information remains available even when the controller is powered down.

During a recovery operation, the controller can retrieve the stored application from the card. Depending on the processor configuration, the memory can also be configured as the source for application loading during startup.

On compatible ControlLogix 5580 and GuardLogix 5580 controllers, the card also serves a diagnostic purpose. When a fault occurs, the controller can automatically write diagnostic information to the installed SD card.

Typical Operating Sequence:

1. Install the 1784-SD2 in the designated SD card socket.
2. The controller detects and accesses the installed memory card.
3. The PLC executes its application during normal operation.
4. An engineer initiates a supported nonvolatile memory save operation.
5. The controller transfers the selected program and tag data to the SD card.
6. The card retains the stored information without continuous power.
7. During maintenance, the saved application can be accessed for recovery.
8. Compatible controller configurations can load stored information during startup.
9. Diagnostic information can also be written to the card following supported fault conditions.

Role in Allen-Bradley ControlLogix Control Architecture

Within the Allen-Bradley ControlLogix architecture, the 1784-SD2 provides nonvolatile storage for controller applications and diagnostic information.

The processor handles logic execution, I/O management, and communication with other automation equipment. The SD card operates as an additional storage resource, allowing important controller information to be retained separately from normal operating memory.

In ControlLogix 5570 systems, the 1784-SD2 can serve as an optional memory card. In ControlLogix 5580 systems, it is supplied as the standard installed SD card.

For GuardLogix 5580 controllers, the card also supports diagnostic data retention. Keeping the card installed allows relevant diagnostic information to be recorded when a fault occurs.

The memory card should be selected according to the processor generation, firmware requirements, and supported storage configuration rather than simply its nominal capacity.

Industrial Applications

Installation and Maintenance

1. Verify Part Number: Confirm that the memory card is Allen-Bradley 1784-SD2 with a storage capacity of 2 GB.
2. Check Controller Compatibility: Verify that the target processor belongs to a supported ControlLogix or GuardLogix controller generation.
3. Check Firmware Requirements: Confirm that the processor firmware and programming software support the intended memory-card operations.
4. Back Up Existing Applications: Save the current controller program and important tag data before performing memory card replacement or maintenance.
5. Inspect the Card: Examine the SD card for physical damage, contamination, or damaged electrical contacts.
6. Prepare the Controller: Follow the applicable Rockwell Automation instructions for accessing the processor’s SD card socket.
7. Install the Memory Card: Insert the 1784-SD2 into the designated socket according to the correct orientation.
8. Verify Card Recognition: Check that the controller recognizes the installed SD card and that the required storage functions are available.
9. Configure Memory Operations: Set the appropriate save and load behavior through the supported Logix programming software.
10. Test Backup Functions: Perform a controlled save operation and verify that the required application information has been stored correctly.
11. Check Diagnostic Storage: For compatible ControlLogix 5580 and GuardLogix 5580 installations, verify that the memory card remains installed for diagnostic data recording.
12. Document Maintenance Results: Record the memory card part number, controller model, firmware version, stored application information, and maintenance date.

Compatible System Components

Recommended Related Models

Key Advantages

• 2 GB Secure Digital nonvolatile memory.
• Compatible with supported ControlLogix 5570 and 5580 configurations.
• Supports compatible GuardLogix 5580 controller applications.
• Stores user programs and controller tag data.
• Supports application backup and restoration.
• Allows configured program loading during controller startup.
• Provides diagnostic data storage for compatible controllers.
• Suitable for industrial controller maintenance and recovery operations.

Technical FAQs

1. What is the storage capacity of the 1784-SD2?

The 1784-SD2 provides 2 GB of Secure Digital storage. It is intended for nonvolatile storage of user programs, tag data, and supported diagnostic information in compatible Logix controllers.

2. Can the 1784-SD2 be used with both ControlLogix 5570 and 5580 controllers?

Yes, the card is supported in applicable configurations of both controller generations. The 5570 family can use it as an optional memory card, while the ControlLogix 5580 family uses it as the standard installed SD card.

3. Why does Rockwell Automation recommend leaving the 1784-SD2 installed in a ControlLogix 5580 controller?

The installed card provides a storage location for diagnostic information. When a controller fault occurs, relevant diagnostic data can be automatically written to the card to assist with fault investigation.

4. What is the difference between the 1784-SD2 and 1784-CF128?

The 1784-SD2 is a 2 GB Secure Digital card used with supported newer Logix controller generations. The 1784-CF128 is a 128 MB CompactFlash card associated with the earlier ControlLogix 5560 platform. They use different memory interfaces and are not interchangeable.