Overview
The Allen-Bradley 1746-NI4 is a high-resolution 4-channel analog input module designed for the SLC 500 programmable controller platform. This module is designed for use with the SLC 500 system from Allen-Bradley / Rockwell Automation. It supports various input types, including voltage and current signals, making it versatile for different applications. Although discontinued as of April 29, 2021, the 1746-NI4 remains a workhorse in legacy manufacturing, process control, and HVAC automation systems worldwide.
Key Features
- 4 Configurable Analog Input Channels: Each channel can be set independently for voltage or current inputs, eliminating the need for separate input cards
- High Resolution 16-Bit Conversion: Offers a resolution of 14 bits and a non-linearity specification of 0.05% of full scale
- Flexible Signal Compatibility: Handles both ±10 V DC and ±20 mA current, adapting to different sensor standards
- Noise Rejection: Equipped with features to minimize electrical noise, which is critical for maintaining signal integrity in industrial environments
- Easy Installation: Designed for easy installation and integration into existing SLC 500 systems, with clear wiring considerations outlined in the accompanying documentation
Technical Specifications
- Data Conversion: 16-bit two’s complement binary via delta-sigma modulation
- Conversion Time: 512 µs for all channels in parallel
- Voltage Input Range: ±10V DC
- Current Input Range: ±20 mA
- Accuracy: 0.384% of full scale at 0 to 60°C (32 to 140°F)
- Input Bandwidth: 10 Hertz for NI4 modules
- Input Impedance: 380K ohms per channel (Series B and later)
- Operating Temperature Range: 0 to 60°C (32 to 140°F)
- Mounting: Single-slot installation in 1746 chassis
- Voltage Category (EMC): 500V DC isolation
- Certifications: C-UL Listed; complies with NEMA ICS 2-230
Typical Applications
The high-resolution conversion ensures accurate representation of analog signals, crucial for industries that require fine process control, such as chemical dosing or temperature regulation. The 1746-NI4 is well-suited for:
- Temperature and pressure monitoring in process industries
- Sensor signal acquisition (thermocouples, transmitters, load cells)
- Flow rate and level measurement
- Machine-mounted analog data logging
- Legacy SLC 500 system retrofits and upgrades
Compatibility & Replacements
Compatible With
- SLC 500 modular processors (1746-L series, 1746-P series)
- SLC 500 fixed I/O systems with analog expansion
- Allen-Bradley RSLogix 500 / Studio 5000 (legacy SLC mode)
- 1746 chassis (single-slot mounting)
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. The 1746-NI4 is a dedicated 4-channel input module and does not directly interchange with analog output modules (NO4I, NO4V) or combination modules (NIO4I, NIO4V). Consult Rockwell Automation documentation for migration paths.
Works With
- Allen-Bradley RSLogix 500 software (legacy SLC programming)
- Hardwired and PLC-based control logic
- Standard 4-20 mA sensor loops and industrial transmitters
- Direct voltage measurement applications (±10V full scale)
- Manual or automated calibration routines documented in the SLC 500 user manual
