Overview
The Allen-Bradley 1746-NI8 is an 8-channel analog input module engineered for SLC 500 programmable logic controllers. This compact, single-slot module converts analog voltage and current signals into digital values that the SLC 500 processor can interpret, making it suitable for applications requiring precise analog signal measurement and closed-loop process control.
Key Features
- 8 Independent Input Channels: Each channel is individually selectable for voltage or current input, supporting mixed-signal configurations without additional modules.
- High-Resolution 16-Bit A/D Conversion: Provides 1 mV or 1 µA input resolution with common-mode rejection of 75 dB at DC and 100 dB at 50/60 Hz.
- Software-Configurable Input Ranges: Supports ±10V DC, 0–10V DC, 1–5V DC, 0–5V DC, 0–20 mA, 4–20 mA, and ±20 mA per channel.
- Rapid Signal Conversion: 6 millisecond update time with 1–75 Hz bandwidth; digital low-pass filter for noise rejection.
- Removable Terminal Block: 18-position screw terminal for quick wiring, maintenance, and replacement without rewiring field connections.
- Diagnostic LEDs: Nine status indicators for real-time input monitoring and troubleshooting.
Technical Specifications
- Input Channels: 8 differential or single-ended, software-selectable per channel
- Input Voltage Ranges: ±10V DC, 0–10V DC, 1–5V DC, 0–5V DC
- Input Current Ranges: 0–20 mA, 4–20 mA, ±20 mA
- A/D Resolution: 16-bit with 1 mV / 1 µA precision
- Update Time: 6 milliseconds per channel
- Bandwidth: 1–75 Hz
- Backplane Current Draw: 200 mA @ 5V DC; 100 mA @ 24V DC
- Power Dissipation: 1 W @ 5V DC; 2.4 W @ 24V DC
- Isolation Voltage: 750V DC / 530V AC (60 seconds)
- Operating Temperature: 0–60°C
- Module Weight: 0.55 lbs
- Mounting: Single-slot, rack-mount chassis (any I/O slot except Slot 0)
- Terminal Style: 18-position removable screw terminal block
- Conversion Method: Successive approximation with continuous autocalibration
Typical Applications
The 1746-NI8 is ideal for industrial automation requiring analog data acquisition, including:
- Process monitoring and control (temperature, pressure, flow measurement)
- Closed-loop proportional valve control and analog feedback systems
- Batch and continuous manufacturing operations
- Machine vision and sensor integration for quality inspection
- Environmental monitoring and HVAC system control
- Load cells, strain gauges, and precision instrumentation interfacing
Compatibility & Replacements
Compatible With
- SLC 500 fixed and modular chassis configurations
- SLC 5/01, SLC 5/02, SLC 5/03, SLC 5/04, SLC 5/05 processors
- Class 1 and Class 3 operation modes (processor dependent)
- Allen-Bradley programming software: RSLogix 500
- Industrial sensors: load cells, pressure transmitters, temperature transducers, flow meters
Replaces / Drop-In Replacement For
The 1746-NI8 Series A directly replaces earlier versions and similar Allen-Bradley analog input modules. Verify compatibility with your system integrator before ordering.
Works With
- RSLogix 500: Standard SLC 500 programming software with built-in function blocks for analog I/O configuration
- Engineering software: Scaling functions, PID instruction blocks, and process monitoring tools
- Communication protocols: Backplane communication with SLC 500 processors; no external networking required
- Input signal types: Differential and single-ended analog signal configurations
