Allen-Bradley 1756-IB16/A ControlLogix DC Digital Input Module

Configured for DC discrete signal acquisition in ControlLogix backplane architectures, the Allen-Bradley 1756-IB16/A (1756-IB16 digital input module) provides direct electrical state sampling of 16-channel 24 V DC field inputs and maps status transitions into the ControlLogix controller through deterministic backplane I/O scanning.

Suffix Breakdown & Model Matrix

The provided configuration defines a fixed module structure 1756-IB16/A with no additional functional suffix segmentation or option-coded electrical variants described in the available specification set.

Hardware Specifications

ControlLogix Backplane Deterministic Input Scanning

The 1756-IB16/A executes DC input state acquisition through ControlLogix backplane cyclic scheduling, where each of the 16 channels is sampled and mapped into controller input tags per scan interval. The module participates in chassis-level deterministic communication using backplane arbitration, ensuring consistent synchronization between field input state transitions and controller task execution. Electronic keying and slot-level identity verification prevent mismatched module configuration during runtime insertion.

Frequently Asked Questions (FAQ)

Q: Can the 1756-IB16/A be replaced under power (RIUP)?
A: Yes, the module supports Removal and Insertion Under Power within ControlLogix chassis rules, provided controller and chassis configuration allow I/O resynchronization.

Q: How is input isolation implemented?
A: Each input channel group is isolated from the backplane with 250 V galvanic isolation to reduce ground potential coupling between field wiring and controller logic.

Q: What determines input update latency?
A: Input delay is typically < 1 ms and is governed by internal opto-isolation switching and ControlLogix backplane scan scheduling.

Field Installation Guidelines

• Install module in a compatible ControlLogix chassis slot with proper backplane engagement.

• Maintain separation between DC input wiring and high-power switching conductors to reduce induced noise coupling.

• Use shielded cables where long field runs are present; terminate shields at a single cabinet ground reference point.

• Verify correct input voltage range (10 to 30 V DC) prior to energizing field circuits.

• Ensure terminal wiring integrity and mechanical seating before applying system power.