Overview
The Allen-Bradley 1746-NI16I is a high-density analog current input module engineered for SLC 500 series programmable logic controllers. This 16-channel module provides isolated analog signal acquisition for complex process automation applications. Each channel converts current-based input signals to digital values with 16-bit resolution, enabling precise monitoring of temperature, pressure, flow, and level across industrial environments.
Key Features
- 16 Isolated Analog Input Channels: Backplane-isolated architecture reduces noise and enhances signal integrity in demanding industrial settings.
- Multi-Range Current Support: Configurable for 0–20 mA, 4–20 mA, ±20 mA, and 0–1 mA input signals.
- 16-Bit Resolution: High-resolution A/D conversion ensures accurate measurement of process variables.
- Single-Slot Design: Occupies one slot in SLC 500 chassis (any position except slot 0) for compact integration.
- Status Indication: 5 LED indicators (one per 4-channel group plus module status) provide real-time diagnostic feedback.
- Sigma-Delta Conversion: Advanced A/D technology for fast, stable signal processing.
Technical Specifications
- Input Channels: 16 single-ended, arranged in 4 isolated groups of 4 inputs each
- Input Ranges: 0–20 mA, 4–20 mA, ±20 mA, 0–1 mA (current-only; not voltage-compatible)
- Resolution: 16-bit
- Backplane Current (5V): 125 mA maximum
- Backplane Current (24V): 75 mA maximum
- Power Consumption: 2.425 W maximum (0.625 W @ 5V DC, 1.8 W @ 24V DC)
- Input Impedance: 249 Ω
- Common Mode Voltage Range: ±10.25 V relative to analog common terminal
- Maximum Input Voltage: ±8 V between analog common and any input terminal
- Maximum Input Current: ±30 mA
- Operating Temperature: −25 to 60°C (−13 to 140°F)
- Non-Operating Temperature: −40 to 85°C (−40 to 185°F)
- Relative Humidity: 5–95% without condensation
- Isolation Voltage: 500 V AC / 710 V DC (60 seconds)
- Update Speed: 9–630 milliseconds (configurable)
- Terminal Block: Removable terminal block (RTB) for single-ended wiring
Typical Applications
The 1746-NI16I is widely deployed in process control, batch operations, environmental monitoring, and closed-loop feedback systems. Common uses include:
- Temperature and pressure monitoring in manufacturing plants
- Flow rate measurement and control in water treatment and chemical processes
- Precision level sensing in tanks and reservoirs
- Industrial sensor integration in legacy SLC 500 automation systems
- Multi-point data acquisition for SCADA and reporting applications
Compatibility & Replacements
Compatible With
- SLC 500 fixed processors (SLC 5/01, 5/02, 5/03, 5/04, 5/05)
- SLC 500 modular processors
- SLC 500 expansion chassis
- RS-Logix 500 programming software
- Allen-Bradley PLC-5 ecosystem (via compatible hardware)
Replaces / Drop-In Replacement For
The 1746-NI16I is a direct replacement for earlier SLC 500 analog input modules in current-signal applications. It supersedes earlier models requiring similar 16-channel current input functionality. Verify part number compatibility with your legacy system documentation.
Works With
- RS-Logix 500 development environment
- Allen-Bradley ControlLogix/CompactLogix (via appropriate gateway modules)
- EtherNet/IP communication (via adapter modules)
- Proportional-Integral-Derivative (PID) control routines
- Data scaling and engineering units conversion within SLC 500 firmware
