Product Overview

The Allen-Bradley 1746-NIO4I is a high-performance analog combination module designed for the SLC 500™ series PLC platform. This module provides a dual-purpose interface by integrating two analog input channels and two analog current output channels into a single-slot hardware design. It is specifically engineered for applications that require high-precision feedback and control, such as closed-loop PID systems, where simultaneous sensor monitoring and actuator command are essential.

By consolidating both input and output functions, the 1746-NIO4I optimizes chassis space and reduces the overall hardware footprint of the SLC controller. Each input channel is independently selectable via software for either voltage or current modes, providing the flexibility to interface with diverse field instruments including pressure transducers, flow meters, and temperature transmitters without the need for hardware jumpers.

Key Technical Characteristics

The 1746-NIO4I is distinguished by its high-resolution conversion capabilities, ensuring that subtle changes in process variables are accurately captured and controlled.

• Mixed I/O Configuration: Features 2 differential inputs and 2 single-ended current outputs, allowing for full-duplex analog control within one module.

• High-Resolution Precision: Utilizes advanced 16-bit analog-to-digital (A/D) and digital-to-analog (D/A) conversion to deliver granular signal processing for demanding industrial tasks.

• Specialized Current Outputs: The two output channels are dedicated to sourcing 4-20 mA signals, the industry standard for driving proportional valves, dampers, and variable speed drives.

• Enhanced Noise Rejection: Built-in electrical isolation and digital filtering circuits protect signal integrity against the electromagnetic interference (EMI) commonly found in heavy industrial motor control centers.

• Backplane Efficiency: Operates using a combination of 5V DC and 24V DC power from the SLC backplane, maintaining low thermal dissipation to ensure long-term component reliability.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1746-NIO4I

• Product Series: SLC 500

• Number of Inputs: 2 Differential Channels (Voltage or Current)

• Number of Outputs: 2 Current Channels (4-20 mA)

• Resolution: 16-Bit

• Input Ranges: ±10V DC, 1-5V DC, 0-5V DC, 0-10V DC; 0-20 mA, 4-20 mA

• Output Range: 0-20 mA (Scalable to 4-20 mA)

• Backplane Current Draw: 55 mA @ 5V DC; 115 mA @ 24V DC

• Isolation: 500V DC (between user I/O and backplane)

• Dimensions: 3.5 x 13.0 x 14.5 cm

• Weight: 0.9 kg

Application and Integration

The 1746-NIO4I is a staple in distributed control systems where precision and space-saving are prioritized. It integrates seamlessly into any SLC 500 fixed or modular chassis and is fully compatible with RSLogix 500 programming software. Its high-resolution data handling makes it ideal for:

• Chemical Processing: Maintaining precise flow rates and mixing ratios through continuous feedback.

• Water Treatment: Regulating pump speeds based on real-time pressure sensor data.

• HVAC Systems: Coordinating large-scale damper positions and fan speeds for environmental control.

• Material Testing: Capturing high-speed load cell data and controlling hydraulic tensioning systems.