Overview
The Allen-Bradley 1746-IB8 is an 8-channel DC digital sinking input module designed for the SLC500 family of small chassis-based programmable controllers. This module features 8 inputs rated at 10-30V DC, with a nominal operating voltage of 24V DC. Manufactured by Allen-Bradley/Rockwell Automation, it is approved for use in all non-hazardous industrial locations and in hazardous industrial locations classified as Class 1, Division 2, Groups A, B, C, or D. The 1746-IB8 delivers reliable input signal acquisition with input filtering, optical isolation, and surge protection for harsh factory environments.
Key Features
- 8 sinking input channels rated at 24 Volts DC
- Operational voltage range of 10–30V DC with backplane current of 50mA at 5V DC
- Typical signal delay of 0.1 ms ON and 0.25 ms OFF at 24V DC
- Dielectric withstand of 1500V AC and isolation testing at 1500V AC between backplane and inputs
- UL and CE-certified with NEMA standard ICS 2-230-tested noise immunity
- Removable terminal blocks for quick field wiring
- Operating temperature range 0–60 °C (32–140 °F) at 5–95% non-condensing humidity
Technical Specifications
- Nominal input current: 8 milliamps at 24V DC
- Power dissipation: up to 1.9 watts during normal operation
- Maximum signal delay: 8 ms ON, 8 ms OFF mode
- Maximum OFF-state current: 1 mA
- Operating vibration: 2.5G at 57–500 Hz; Shock rating: 30G
Typical Applications
- Discrete input signal acquisition in assembly automation and material handling systems
- Limit switch monitoring for industrial machinery (presses, conveyors, packaging equipment)
- Sensor interface modules in temperature, pressure, and flow control loops
- Safety and alarm circuit input modules in manufacturing automation
- Equipment status monitoring (run/stop/error states) in plant automation systems
Compatibility & Replacements
Compatible With
- Allen-Bradley SLC 500 chassis and modular processors (all fixed and modular SLC500 models)
- SLC 500 12-slot, 16-slot, and 32-slot chassis variants
- Allen-Bradley standard and high-current backplanes
- Compatible within the SLC500 input module family including 1746-IA4, 1746-IA8, 1746-IA16, 1746-IB16, 1746-IC16, and similar I/O modules
Replaces / Drop-In Replacement For
- Series A, Series B, and Series C versions of the 1746-IB8 are mechanically and functionally interchangeable
- Direct replacement for legacy 1746-IB8 modules in existing SLC500 systems requiring input module upgrades or maintenance spares
Works With
- Allen-Bradley RSLogix 500 programming software for ladder logic configuration
- RSLinx Classic and RSLinx Enterprise for network communication and diagnostics
- Allen-Bradley FactoryTalk View and HMI/SCADA systems for real-time monitoring
- Bulletin 1747 communication modules for industrial networking (Ethernet, DH+, Remote I/O)
