The Allen‑Bradley 1756‑IB32/B is a high‑density digital DC input module from the ControlLogix family, designed to deliver reliable field signal acquisition for demanding industrial automation environments. As a 32‑point sinking input module, the 1756‑IB32/B converts field device statuses (sensors, pushbuttons, limit switches) into logic signals for the PAC controller, supporting a wide operating voltage range of 10 – 31.2V DC (nominal 12/24V DC). This Series B revision offers enhanced component traceability and firmware stability, making it a preferred choice for both new system builds and legacy upgrade projects within the Rockwell Automation ecosystem.

Technical Specifications

The 1756‑IB32/B module is engineered for precision and noise immunity, featuring 32 input channels partitioned into 2 isolated groups of 16 points each. Key electrical parameters include:

• Input Voltage Range (Operating): 10 – 31.2V DC (sinking)

• Nominal Input Voltage: 12 – 24V DC

• Input Current (ON‑state, min.): 2.0 mA @ 10V DC

• Input Current (ON‑state, max.): 5.5 mA @ 31.2V DC

• Off‑state Max. Input Current: 1.5 mA (prevents false triggers)

• Off‑state Max. Voltage: 5V DC

• Backplane Current Draw: 120 mA @ 5.1V DC + 2 mA @ 24V DC

• Total Backplane Power: 0.66 W

• Max. Power Dissipation: 6.2 W @ 60 °C

• Thermal Dissipation: 21.1 BTU/hr @ 60 °C

Input Delay & Filtering

The 1756‑IB32/B provides flexible input filtering to combat electrical noise in harsh factory floors:

• OFF → ON Hardware Delay: ≤ 380 µs + user‑selectable filter time (0, 1, or 2 ms)

• ON → OFF Hardware Delay: ≤ 420 µs + user‑selectable filter time (0, 1, 2, 9, or 18 ms)

• Maximum Inrush Current: 250 mA (decays to <37% in 22 ms without activation)

Configurable filter times allow engineers to balance response speed against signal stability—critical for applications with contact bounce or proximity sensor chatter. The module’s electronic keying ensures correct slot placement, preventing damage from mismatched firmware or I/O types.

Environmental & Mechanical Ratings

The Allen‑Bradley 1756‑IB32/B operates reliably across a wide thermal envelope:

• Operating Temperature: 0 – 60 °C (32 – 140 °F)

• Storage Temperature: -40 – 85 °C

• Relative Humidity: 5 – 95% (non‑condensing)

• Enclosure Type: Open (IP20 protection when installed in a chassis)

• Agency Approvals: UL 508, CSA, CE, ATEX (for hazardous locations, Class I, Division 2)

Installation & Wiring Guide

Mounting the 1756‑IB32/B requires a single slot in any ControlLogix chassis (e.g., 1756‑A4, ‑A7, ‑A10, ‑A13, ‑A17). Follow these best practices:

1. Slot Selection: Insert the module into an available slot with power off. Engage the upper and lower locking tabs to secure it.

2. Removable Terminal Block (RTB): The module ships with a 36‑pin RTB (compatible with 1756‑TBCH or 1756‑TBS6H). Use shielded twisted‑pair cables for field wiring to reduce EMI.

3. Wiring Polarity: Wire sinking field devices (e.g., NPN sensors) with the common (DC‑) connected to the RTB’s return terminals. Apply DC+ to the input channel terminals.

4. Chassis Grounding: Connect the chassis ground terminal to a low‑impedance earth ground to ensure proper surge protection.

5. Configuration: After physical installation, set the module’s RPI (Requested Packet Interval), communication fault behavior, and input filter times via Studio 5000 Logix Designer®.

Packaging List

(Note: Certificate and 12‑month warranty clause are intentionally omitted per your request.)

• 1 × Allen‑Bradley 1756‑IB32/B input module (Series B, Rev B)

• 1 × 36‑pin Removable Terminal Block (RTB) (compatible with 1756‑TBCH / 1756‑TBS6H)

• 1 × RTB housing retaining clip (pre‑installed)

• 1 × Product information sheet (quick‑start guide with wiring diagrams)

• Anti‑static protective packaging

Shipping & Logistics

All orders for the 1756‑IB32/B are dispatched within 24 hours (business days) via FedEx, UPS, or DHL with full tracking and insurance. Express shipping options are available at checkout. Please note that the gross weight (0.45 kg) and dimensions (12.5 × 8.2 × 5.8 cm) apply to standard domestic and international courier calculations.

Frequently Asked Questions (FAQ)

Q1: Can the 1756‑IB32/B accept AC input signals?
No. The 1756‑IB32/B is a DC sinking input module rated for 10‑31.2V DC only. For AC inputs, refer to the 1756‑IA series or 1756‑IM series modules.

Q2: Is the 1756‑IB32/B compatible with a 1756‑CNB ControlNet bridge?
Yes. The 1756‑IB32/B communicates over the ControlLogix backplane. When used with a 1756‑CNB or 1756‑ENBT bridge, it supports distributed I/O configurations with configurable RPI (typically 0.5 – 750 ms).

Q3: How do I replace a faulty 1756‑IB32/B without rewiring all field cables?
Simply unplug the existing RTB from the old module, remove the module from the chassis, insert the replacement 1756‑IB32/B, and reattach the same RTB. The electronic keying will verify compatibility upon power‑up.

Q4: What is the difference between Series B and earlier revisions of the 1756‑IB32?
Series B (Rev B) includes updated component sourcing, improved thermal dissipation characteristics, and better firmware compatibility with Studio 5000 v32 and later. It remains form‑fit‑function interchangeable with Series A.

Q5: What filter time should I choose for high‑speed counting applications?
For fast pulse signals (e.g., encoder or high‑speed counter inputs), set the filter time to 0 ms on the 1756‑IB32/B to achieve the minimum hardware delay (380 µs OFF→ON / 420 µs ON→OFF). For noisy switch contacts, use 1 ms or 2 ms to debounce.