Allen-Bradley 1791DS-IB16 Safety Input Module

Configured for discrete safety signal acquisition in Guard I/O networks, the Allen-Bradley 1791DS-IB16 (1791DS-IB16 Safety Input Module) provides direct physical and electrical execution of fail-safe input monitoring.

Hardware Specifications

Deterministic Safety Network Integration

The 1791DS-IB16 operates within the Guard I/O 1791DS/ES platform, utilizing deterministic network communication to ensure timely delivery of safety-critical data. Firmware flash compatibility is strictly enforced; updates must be managed through the controller's safety task configuration to maintain the integrity of the safety signature. The module supports I/O density scaling within a Guard I/O cluster, allowing for modular expansion of safety inputs. Backplane bus communication velocity is optimized to meet functional safety response time requirements, and users must ensure the network scan interval is configured to support the safety loop's latency constraints.

Frequently Asked Questions (FAQ)

Q: Does the 1791DS-IB16 support hot-swapping under power?

A: Hot-swapping is not supported. All power to the module and the associated network segment must be removed before removing or inserting the unit to prevent backplane damage and ensure compliance with safety installation protocols.

Q: Can single-channel inputs be combined for dual-channel safety functions?

A: Yes. While the inputs are physically single-channel, dual-channel configurations are achieved at the safety controller level by mapping two inputs and configuring the safety function block for discrepancy monitoring and time-based fault detection.

Field Installation Guidelines

1. Mounting: Install the module on a standard 35 mm DIN-rail. Ensure the locking mechanism is fully engaged to maintain structural stability.
2. Grounding: Connect the module chassis ground terminal to a low-impedance common ground reference to mitigate electrical interference.
3. Wiring: Use 22-14 AWG shielded copper wire for input connections. Keep input signal wiring separated from high-voltage AC lines to prevent induced noise.
4. Input Logic: Ensure input signals are derived from voltage sources that meet the defined 11 VDC minimum threshold for ON state and 5 VDC maximum threshold for OFF state.
5. Shielding: Terminate cable shields at the designated ground plane to ensure shielding continuity, avoiding ground loops that may impact signal sensitivity.