Product Analysis: Allen-Bradley 1746-IB32
The Allen-Bradley 1746-IB32 is a high-density 32-point digital DC input module for the SLC 500™ platform. This module is designed for applications where space in the I/O chassis is limited, providing twice the capacity of standard 16-point modules in a single slot. It is a 24V DC sinking module, making it ideal for large-scale industrial projects requiring massive discrete signal counts.
Advanced Connectivity and High Density
Unlike standard SLC modules that use a terminal block, the 1746-IB32 utilizes a high-density 40-pin connector. This requires specialized wiring harnesses or the use of 1492 interface modules to manage the 32 input leads. This design significantly reduces the physical footprint of the PLC system while maintaining high-speed signal processing capabilities across all 32 channels.
Key Technical Characteristics
- Number of Inputs: 32 Points.
- Voltage Category: 24V DC (Sinking).
- Operating Voltage Range: 15–30V DC.
- Backplane Current (5V DC): 0.050 A.
- Off-State Voltage (Max): 5.0V DC.
- On-State Current (Min): 5.1 mA at 15V DC.
- Input Delay (Max): 3ms (on/off) – faster than 16-point models.
Thermal and Electrical Efficiency
Despite its high density, the 1746-IB32 is engineered for thermal stability. It features two isolated groups of 16 inputs each, allowing for different power sources if necessary. The module’s extremely fast 3ms response time makes it suitable for high-speed counting and packaging applications where standard 8ms delays are unacceptable. Its 1500V AC isolation ensures robust protection for the SLC processor.
| Category | Parameter |
| Total Inputs | 32 Points |
| Connector Type | 40-pin (requires 1746-N3 or 1492 cable) |
| Max Off-State Current | 1.5 mA |
Product Utility
The 1746-IB32 is the preferred choice for modernizing SLC systems where additional I/O is needed without adding new chassis. It is commonly found in complex conveyor systems and high-bay warehouse automation where high signal density is a requirement.
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For ultra-high density I/O, this 32-point card is best utilized in a large 1746-A10 10-slot chassis.
