Overview
The Allen-Bradley 1746-NI8 is a single-slot analog input module designed for SLC 500 fixed and modular chassis. This 8-point analog input module provides non-isolated differential channels with selectable voltage (±10V DC) or current (4–20 mA) input ranges, making it suitable for integrating analog sensors and instrumentation into SLC 500 control systems. The module performs successive approximation analog-to-digital conversion with programmable low-pass digital filtering for reliable signal acquisition.
Key Features
- Eight analog input channels with independently selectable voltage or current input configuration
- Fast signal conversion with 6 millisecond update time and 1–75 Hz bandwidth
- High resolution conversion: 16-bit analog-to-digital conversion for precise data acquisition
- Programmable digital filtering with continuous autocalibration for signal conditioning
- Low backplane current draw: 200 mA @ 5V DC, 100 mA @ 24V DC
- Isolated backplane design with 750V DC isolation voltage for noise immunity
Technical Specifications
- Input Voltage: ±10V DC (selectable per channel)
- Input Current: 4–20 mA (selectable per channel)
- Number of Inputs: 8 differential channels
- Conversion Method: Successive approximation A/D converter
- Resolution: 16 bits
- Update Time: 6 milliseconds
- Bandwidth: 1–75 Hz
- Backplane Current @ 5V DC: 200 mA
- Backplane Current @ 24V DC: 100 mA
- Power Dissipation: 1 W @ 5V, 2.4 W @ 24V
- Isolation Voltage: 750V DC
- Operating Temperature: 0–60°C
- Mounting: Rack mount, single I/O slot (not Slot 0)
- Weight: 0.55 lbs
- Series: SLC 500
Typical Applications
The 1746-NI8 is commonly deployed in:
- Temperature and pressure sensor data acquisition in manufacturing processes
- Level, flow, and position monitoring in process control systems
- Legacy machine control upgrades requiring analog feedback integration
- Data logging and real-time monitoring applications with time-sensitive requirements
- Multi-channel analog input expansion for existing SLC 500 systems
Compatibility & Replacements
Compatible With
- SLC 500 fixed I/O chassis (non-slot 0 positions)
- SLC 500 modular I/O chassis
- SLC 500 controllers running APS (Allen-Bradley PLC/5 and SLC instruction sets)
- RSLogix 500 (legacy programming software)
- EtherNet/IP gateway modules for remote I/O connectivity
- Allen-Bradley chassis backplane architecture
Replaces / Drop-In Replacement For
- Earlier SLC 500 analog input modules requiring upgrade to 16-bit resolution
- Verify compatibility with your system integrator before ordering legacy module replacements
Works With
- RSLogix 500 programming platform
- SLC 500 instruction set and function blocks
- Allen-Bradley Channel IO (DH-485, DH+) communication modules
- Standard SLC 500 I/O configuration routines
- Analog scaling and conversion subroutines in RSLogix 500
