Allen-Bradley 1791DS-IB8XOB8 Guard I/O DeviceNet 16-Point Safety Digital Combination Module

Product Overview

The Allen-Bradley 1791DS-IB8XOB8 serves as a high-integrity safety I/O block designed for distributed safety control networks using the DeviceNet protocol. This combination module allows automation engineers to interface safety-critical field devices directly with safety controllers, eliminating localized, complex hardwiring. By executing internal safety diagnostics and communicating via the CIP Safety protocol over DeviceNet, this unit satisfies the strict requirements for functional machine safety up to Safety Integrity Level (SIL) 3 and Category 4/PLe standards.

Core Functional Characteristics and Technical Performance

• Safety I/O ConfigurationThe module establishes reliable field connections through 8 safety inputs and 8 solid-state safety outputs, alongside 4 dedicated pulse test outputs. The hardware utilizes the test outputs to detect cross-channel shorts and broken wires, thereby reinforcing system architecture integrity. The safety inputs operate on a 24V DC current-sinking configuration, while the sourcing solid-state safety outputs deliver 0.5A per channel to control actuators, safety contactors, or safety relays safely.
• Network Intelligence and SecurityTo protect the industrial setting from malicious or accidental alterations, the hardware incorporates a secure configuration lock. This lock restricts unauthorized configuration changes once the safety supervisor commissions the network. Furthermore, the internal processor runs continuous self-diagnostic routines to monitor the physical and communication health of individual channels and reports comprehensive status bytes back to the master controller.
• Industrial Ergonomics and HousingEngineered with a compact IP20 enclosure, the compact module mounts directly onto standard DIN rails to optimize cabinet space footprint. The hardware withstands substantial mechanical stress, tolerating operational vibrations up to 5G. Additionally, the unit functions seamlessly within a broad temperature window, making it highly suitable for deployment near heavy manufacturing machinery.

Technical Specifications

• Manufacturer: Allen-Bradley / Rockwell Automation
• Product Series: Guard I/O 1791DS Series
• Catalog Number: 1791DS-IB8XOB8
• Hardware Function: DeviceNet Safety Digital Combination Module
• Safety Inputs: 8 Channels (Current Sinking)
• Safety Outputs: 8 Channels (Solid-State Sourcing, 0.5A Max)
• Pulse Test Outputs: 4 Channels
• Nominal Operating Voltage: 24V DC (20.4 to 26.4V DC Range)
• Safety Ratings: SIL 3 (IEC 61508), Category 4 / PLe (EN ISO 13849-1)
• Physical Dimensions: 80 mm x 196 mm x 77 mm
• Net Weight: 0.2 kg
• Harmonized Tariff Code (HS Code): 8537101190

Industrial Applications

• Robot manufacturing cells requiring secure monitoring of light curtains, E-stop pushbuttons, and interlock switches.
• Material handling conveyors necessitating distributed safety blocks over expansive DeviceNet line topologies.
• Automotive stamping operations requiring high vibration tolerance and immediate solid-state safety circuit interruptions.
• Packaging machines utilizing dual-channel safety devices to control safety power elements.