Allen-Bradley 1756-IB32/B ControlLogix Digital DC Input Module

Configured for 10–31.2 VDC discrete signal acquisition in ControlLogix backplane architectures, the Allen-Bradley 1756-IB32/B (1756-IB32/B Digital DC Input Module) provides 32-channel grouped digital input acquisition across two 16-point input groups within ControlLogix Series B chassis systems. Field voltage states are converted into backplane-transferred discrete status data for controller scan processing.

Input acquisition is executed via chassis slot arbitration, where grouped channel blocks are sampled and synchronized with ControlLogix execution cycles.

Suffix Breakdown & Model Matrix

The 1756-IB32/B is a single Series B catalog configuration. No additional suffix segmentation or option coding structure is defined in the provided dataset. No structural decomposition is applied.

Hardware Specifications

ControlLogix Backplane Communication and Grouped Input Architecture

The module communicates through ControlLogix backplane cyclic scheduling, where grouped input data is transferred via slot-based deterministic arbitration. Each 16-point group is scanned as a shared electrical domain, and state updates are synchronized with controller task execution cycles.

Backplane data exchange is executed through internal bus communication rather than external field protocol timing. Input status aggregation is performed at group level prior to controller memory mapping, resulting in reduced per-channel isolation granularity compared to individually isolated modules.

Thermal load distribution is managed across chassis backplane power domains, where dissipation is calculated at module level and contributed to enclosure-level heat balance.

Frequently Asked Questions (FAQ)

Q: How are the 32 inputs structured internally?
A: The module organizes 32 inputs into two groups of 16 points each, sharing grouped isolation domains per section.

Q: What is the impact of backplane current draw on chassis design?
A: The module draws 120 mA at 5.1 VDC and 2 mA at 24 VDC, which must be included in total chassis backplane power budgeting.

Q: What does the 5 V maximum off-state voltage indicate?
A: It defines the maximum leakage threshold tolerated at input terminals when channels are in OFF state, ensuring valid logic-level discrimination.

Field Installation Guidelines

Install the module into a compatible ControlLogix chassis with verified backplane power capacity. Ensure full seating of terminal assemblies and correct alignment of both 16-point input groups.

Maintain separation between DC input wiring and high-energy switching conductors to reduce induced coupling across grouped channels. Use single-point grounding for shield termination to maintain signal reference stability.

Verify input group mapping and voltage configuration in ControlLogix programming software prior to energizing field circuits. Avoid mixing external reference potentials across grouped input sections.