Allen-Bradley 1791ES-IB16 I/O Module

The 1791ES-IB16 is a 24 VDC EtherNet/IP safety input module belonging to the Allen-Bradley CompactBlock Guard I/O family. Designed for safety-critical machine automation, it provides 16 current-sinking safety input channels capable of evaluating single- or dual-channel safety devices. The unit communicates using the CIP Safety protocol over EtherNet/IP, seamlessly interfacing with GuardLogix, GuardPLC, or SmartGuard controllers to meet SIL 3 and Category 4 / PLe requirements.

Safety Input Configuration and Diagnostic Pulse Testing

The 1791ES-IB16 can be configured for 16 single-channel safety inputs or 8 dual-channel safety inputs depending on system safety architecture. It incorporates built-in test pulse outputs that continuously monitor field wiring for short circuits, cross-faults, and ground faults without interrupting operational signals. Point-level channel diagnostics provide immediate feedback regarding open loops, line faults, or channel discrepancies.

Network Integration and Cabinet Installation

Integrating CIP Safety over standard EtherNet/IP enables safety signals and standard control data to traverse the same network cable. Network configuration and safety signature management are managed through Studio 5000 Logix Designer via assigned Safety Network Numbers (SNN). The module features an integrated DIN rail mount, removable terminal blocks for simple field replacement, and front-panel status LEDs indicating module health, communication status, and individual input channel states.

Frequently Asked Questions

Q: Can the 1791ES-IB16 inputs be configured for both single-channel and dual-channel safety devices?

A: Yes, the module supports configuration as either 16 independent single-channel safety inputs or 8 dual-channel safety input pairs via programming software.

Q: What is the purpose of the pulse test outputs on the 1791ES-IB16?

A: Pulse test outputs supply power to field contact devices (such as E-stops or interlocks) while injecting microscopic low pulses to detect wire-to-wire shorts and short-circuits to 24 VDC power.