Allen-Bradley 1746-ITB16 — 16-Channel High-Speed Digital Input Module
Overview
The Allen-Bradley 1746-ITB16 is a high-speed discrete digital input module designed for SLC 500 modular chassis. This Series C module provides 16 sinking input channels and is optimized for applications requiring fast pulse capture and rapid signal response. The module receives digital input signals and stores the data in its image table for retrieval by all SLC 500 processors, making it an essential component in time-critical control systems.
Key Features
- 16 discrete digital input channels (current sinking configuration)
- High-speed response — up to 1 kHz pulse frequency with SLC 5/03 or 5/04 using DII instructions
- Operating voltage: 10–30V DC, nominal 24V DC
- Compact modular design fits standard SLC 500 chassis
- Individual LED status indicators for each input channel
- Fast on/off signal transition times (0.3 ms on-state, 0.5 ms off-state delay)
- Removable terminal blocks for easy wiring and module replacement
Technical Specifications
- Input Channels: 16 digital inputs, current sinking
- Input Voltage Range: 10–30V DC
- Nominal Input Voltage: 24V DC
- Input Current (Nominal): 8 mA at 24V DC
- Maximum Off-State Voltage: 5V DC
- Maximum Off-State Current: 1.5 mA
- On-State Delay: 0.3 ms
- Off-State Delay: 0.5 ms
- Backplane Current Load: 85 mA at 5V DC
- Maximum Power Dissipation: 3.6 W
- Operating Temperature Range: 0°C to +60°C
- Isolation Voltage: 1500V RMS (input to backplane)
- Part Number: 1746-ITB16
- Series: C
- Mounting: SLC 500 modular chassis slot
Typical Applications
The 1746-ITB16 is deployed in:
- High-speed encoder and pulse counter interfaces (up to 2 kHz with gray-code encoders)
- Emergency stop signal monitoring and interlock circuits
- Discrete position sensing and proximity switch input capture
- Motion control systems requiring rapid input response
- Process equipment with multiple discrete sensor inputs
- Packaging and material handling machinery
Compatibility & Replacements
Compatible With
- SLC 500 fixed and modular processors (SLC 5/01, 5/02, 5/03, 5/04, 5/05)
- SLC 500 modular chassis (1746-A4, 1746-A10, 1746-A13)
- SLC 500 distributed I/O via Remote I/O (RIO) and Ethernet adapters
- Allen-Bradley RSLogix 500 programming software
- Ladder Logic and DII (Discrete Input Interrupt) instructions
- Gray-code encoders (Allen-Bradley 845D recommended)
Replaces / Drop-In Replacement For
The 1746-ITB16 replaces earlier Series B versions (1746-ITB16 Series B). This module is a direct replacement for existing SLC 500 high-speed discrete input requirements. Always verify chassis slot and configuration before replacement to ensure compatibility with your specific processor model.
Works With
- RSLogix 500 (ladder and structured logic programming)
- Allen-Bradley Studio 5000 (legacy SLC import/migration)
- Remote I/O communication over coax and Ethernet
- Discrete Input Interrupt (DII) instructions for time-critical polling
- SLC 500 chassis backplane communication protocol
