Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | Allen-Bradley 1746-IB32 |
| Manufacturer | Allen-Bradley (Rockwell Automation) |
| Product Type | Digital DC Input Module |
| Series | SLC 500 |
| Number of Inputs | 32 |
| Input Type | Sinking (NPN) |
| Points per Common | 8 points per common (4 groups total) |
| Operating Voltage | 15-30V DC @ 50°C; 15-26.4V DC @ 60°C |
| Nominal Input Voltage | 24V DC |
| Nominal Input Current | 5.1 mA @ 24V DC |
| Signal Delay (Max) | 3 ms (On and Off) |
| Backplane Current (5V DC) | 50 mA |
| Backplane Current (24V DC) | 0 mA |
| Isolation from Backplane | 1500V AC for 1 minute |
| Off-State Voltage (Max) | 5.0V DC |
| Off-State Current (Max) | 1.5 mA |
| Power Dissipation | 6.65W total (0.20W per point) |
| Mounting | SLC 500 Chassis, Slot 2 or Higher |
| Fuse Protection (Series A/B/C) | 2.5A non-replaceable fuse per common |
| Fuse Protection (Series D) | Not fused |
| Lifecycle Status | Discontinued (November 24, 2022) |
Main Features and Advantages
High-Density 32-Channel Design: The Allen-Bradley 1746-IB32 delivers exceptional channel density by integrating 32 input points within a single-width SLC 500 module, maximizing the use of valuable chassis slots. This density is achieved without compromising signal integrity or isolation, as the module maintains 1500V AC isolation between the backplane and field circuits . For applications requiring extensive sensor monitoring—such as automated assembly lines, material handling systems, and process control panels—the Allen-Bradley 1746-IB32 reduces the total module count, associated wiring, and cabinet footprint compared to lower-density alternatives.
Sinking Input Configuration with Group Isolation: The Allen-Bradley 1746-IB32 employs a current-sinking input design, where field devices switch the DC negative return path to the module inputs. The 32 channels are organized into four groups of eight points, with each group sharing a common terminal and offering group-to-group isolation . This configuration simplifies wiring of NPN-type sensors and provides flexibility in grouping inputs by function, machine zone, or voltage source, reducing cross-talk and improving troubleshooting efficiency.
Comprehensive Diagnostic Indication: Every input channel on the Allen-Bradley 1746-IB32 features an individual LED status indicator, providing real-time visual confirmation of each point’s on/off state . This per-channel visibility is invaluable during commissioning and maintenance, allowing technicians to verify sensor operation, diagnose wiring faults, and confirm program logic response without requiring external test equipment or software monitoring. The module also includes a module-level status LED for power and fault indication.
Series-Dependent Protection Features: Early series of the Allen-Bradley 1746-IB32 (Series A, B, and C) incorporate a non-replaceable 2.5A fuse per common group to protect external wiring from overcurrent damage . Series D and later modules eliminate these fuses, relying on external circuit protection instead . This evolution reflects changing installation practices and simplifies the module by removing a non-serviceable component, while still maintaining robust electrical protection through upstream protective devices.