Allen-Bradley 1746-IV32 SLC 500 24VDC 32-Channel Digital Input Module

Product Overview

When upgrading or maintaining an SLC 500 control system, the Allen-Bradley 1746-IV32 delivers a cost-effective solution for discrete input monitoring. This 24VDC digital input module provides 32 channels organized into four groups of eight, allowing efficient wiring and reduced installation costs. By using a single-slot design, it minimizes chassis space usage and lowers overall system footprint—directly contributing to lower enclosure and cabling expenses. The module is part of the proven SLC 500 family, ensuring long-term reliability and easy replacement.

Technical Specifications

The 1746-IV32 operates with an input voltage range of 15 to 30V DC at 50°C and 15 to 26.4V DC at 60°C, offering flexibility in varying thermal environments. Its minimum on-state voltage is 15.0V DC, and maximum off-state voltage is 5.0V DC, with off-state current limited to 1.5 mA. Nominal input current is 5.1 mA at 24V DC. The module draws 0.050 Amperes at 5 Volts DC from the backplane, keeping power consumption low and reducing energy costs over the system lifecycle. Signal delay is 3 ms for ON and 8 ms for OFF transitions, ensuring fast response for time-sensitive applications. Storage temperature ranges from -40°C to +85°C, and operating temperature from 0°C to +60°C, with relative humidity of 5 to 95% without condensation.

Industry Applications

In material handling systems, the 1746-IV32 monitors conveyor belt sensors and limit switches, with its 32 inputs handling multiple zones simultaneously. The 24VDC sourcing design simplifies wiring with common industrial sensors, reducing installation time and material costs. In packaging machinery, the module detects product presence and position, where its 3 ms ON delay ensures accurate timing for high-speed lines. For water treatment facilities, the 1746-IV32 monitors valve positions and level switches, operating reliably across the 15-30VDC range even in fluctuating power conditions. Each application benefits from the module's 1500V AC isolation from the backplane, protecting the control system from electrical noise and reducing downtime.

Installation Guide

Install the 1746-IV32 into any SLC 500 chassis slot—local, extended, or distributed I/O rack. Ensure the chassis power supply provides sufficient backplane current (0.050 A at 5V DC). Wire each group of eight inputs with a common return, using the 2.5A electronically-fused common per group. Verify input voltage stays within 15-30V DC at 50°C or 15-26.4V DC at 60°C. For Series A, B, and C modules, note the non-replaceable internal fuses per common; Series D modules lack group fusing. Always follow Rockwell Automation guidelines for proper grounding and noise immunity per NEMA ICS 2-230.

Maintenance & Reliability

Routine inspection of the 1746-IV32 should focus on environmental conditions—keep ambient temperature below 60°C and humidity within 5-95% non-condensing. The module withstands 2.5G vibration at 57-200 Hz and 30G operational shock, reducing failure risk in industrial environments. Because the fuses are non-replaceable, avoid overcurrent conditions by verifying load wiring. The module's 0.2W per point heat dissipation (6.65W total) requires adequate airflow in the enclosure. Regular cleaning of the chassis and module contacts prevents signal degradation, extending service life and lowering total cost of ownership.

Compatibility & Integration

The 1746-IV32 integrates seamlessly with any SLC 500 processor, including 5/01, 5/02, 5/03, 5/04, and 5/05 models. It works in local, extended, and distributed I/O racks, providing flexibility for system expansion. The module uses the standard SLC 500 backplane interface, requiring no special adapters. For mixed-voltage systems, the 1746-IV32 handles 24VDC inputs while other modules manage 120VAC I/O, as noted in its application as a combination 120VAC I/O module. This compatibility reduces spare parts inventory and simplifies system design.

Selection Guide & Purchasing Advice

Before ordering the 1746-IV32, verify your system's backplane current capacity and ensure the input voltage matches your sensor outputs. The module is available in Series A, B, C, and D—confirm which series your system requires, as fuse configurations differ. BluePLC Industrial stocks genuine Allen-Bradley 1746-IV32 modules with full warranty and technical support. Contact us to check current lifecycle status and availability. For complete technical specifications, please contact BluePLC Industrial.