Overview
The Allen-Bradley 1771-SDN is a 2-channel DeviceNet scanner module engineered for PLC-5 processors in the 1771 I/O family. This module acts as the primary interface between a PLC-5 controller and DeviceNet networks, enabling seamless communication with distributed field devices, drives, sensors, and remote I/O nodes. It supports both scanning and messaging operations, making it essential for legacy PLC-5 automation architectures that require DeviceNet connectivity.
Key Features
- 2-Channel DeviceNet Interface — Two independent DeviceNet ports allow connection of up to 63 nodes per channel
- Block Transfer and Discrete I/O Support — Communicates with PLC-5 processor via Block Transfer reads/writes and DIO transfers
- Advanced Messaging — Supports strobe, poll, Change of State (COS), and cyclic messaging for flexible device communication
- LED Diagnostics — Status indicators, reset button, and node address display on front panel for easy troubleshooting
- Series A/B/C Backward Compatibility — Series B and C modules are drop-in replacements with configuration switch adjustment for seamless upgrades
Technical Specifications
- Communication Rate: 125 kbps (Kbits/s)
- DeviceNet Channels: 2 independent ports
- Maximum Nodes per Channel: 63 DeviceNet nodes
- Operating Temperature: 0–60°C
- Backplane Current: 1.2 A @ 5V
- Module Type: Printed Circuit Board (PCB), single-slot chassis mount
- Configuration: Software setup via RSNetWorx; hardware node address and chassis settings via configuration switches
- Messaging Protocol: DeviceNet Scan I/O and Process Messages
Typical Applications
- Connecting distributed I/O and remote racks to legacy PLC-5 systems
- Controlling DeviceNet-enabled drives, sensors, and variable frequency drives (VFDs)
- Implementing decentralized control architecture in existing 1771 automation racks
- Upgrading and maintaining legacy PLC-5 control systems with DeviceNet integration
- Data exchange between PLC-5 processors and industrial visualization and SCADA systems
Compatibility & Replacements
Compatible With
- Allen-Bradley PLC-5 processors
- 1771-A1B through 1771-A4B I/O chassis and later models
- DeviceNet field devices and industrial nodes
- RSNetWorx configuration software
- Block Transfer messaging and Discrete I/O communication protocols
Replaces / Drop-In Replacement For
- 1771-SDN Series A (full replacement with electronic keying adjustment)
- 1771-SDN Series B (fully interchangeable with switch 5 configuration)
Works With
- RSNetWorx DeviceNet configuration and commissioning software
- DeviceNet Protocol (industrial networking standard)
- PLC-5 ladder logic and structured text programming environments
- 1771 series I/O modules and communication modules
