Allen-Bradley 1785-PFB Profibus Module

The Allen-Bradley 1785-PFB acts as a sophisticated communication gateway for the PLC-5 controller platform. This Series B module enables seamless integration between Rockwell Automation systems and Profibus DP networks. By supporting high-speed data exchange, the module allows PLC-5 processors to communicate effectively with diverse remote I/O peripherals and third-party automation hardware. Furthermore, the unit features a dual-role architecture, allowing it to function as either a DP master or a DP slave depending on the system configuration. This versatility makes it an essential component for facilities running multi-vendor hardware environments.

Technical Specifications

Operational Safety and Configuration

Proper installation is critical for protecting the 1785-PFB internal components. Users must never insert or remove the module while the I/O chassis has active power, as this can cause permanent electrical damage. During setup, the DP master must manage specific configuration data for every slave on the network, including address assignments and bus parameters. Once configured, the module maintains stable operation in demanding industrial settings. Although Rockwell Automation discontinued this series in 2011, it remains a vital legacy component for maintaining existing PLC-5 infrastructure and distributed control networks.

Common Industrial Applications

The 1785-PFB facilitates robust connectivity in several automation sectors:

• Distributed I/O: Linking PLC-5 racks to remote Profibus-compatible sensor blocks.
• Third-Party Integration: Connecting Allen-Bradley controllers to Siemens or ABB drives.
• Legacy System Expansion: Extending the life of PLC-5 systems with modern fieldbus devices.
• Process Automation: Managing complex data transfers in chemical or water treatment plants.