Overview
The Allen-Bradley 1746-IA8 is an 8-point AC digital input module designed for integration into SLC 500 I/O chassis. This module interfaces with field devices such as AC-powered sensors, limit switches, and pushbuttons, converting 120V AC signals into PLC-compatible logic levels. The 1746-IA8 provides dependable signal acquisition in general-purpose automation applications and is built for reliable performance in industrial control environments.
Key Features
- 8 grouped AC digital input channels for compact I/O expansion
- 100–120V AC rated inputs with 85–132V AC operating range at 47–63 Hz
- Fast response times: 35 ms ON / 45 ms OFF
- Optical isolation between field and logic circuitry for noise immunity
- Single chassis slot installation with standard 1746 I/O compatibility
- North American Hazardous Location Approval for classified environments
Technical Specifications
Electrical:
- Input Voltage: 100–120V AC (nominal); 85–132V AC (operating range)
- Frequency: 47–63 Hz
- Input Current: 12 mA nominal at 120V AC
- Signal Response: 35 ms ON / 45 ms OFF
- Backplane Current (5V DC): 50 mA
- Power Dissipation: 0.27 W per point; 2.4 W maximum total
Physical:
- Dimensions: 5″ W × 2″ D × 6″ H (13 cm × 5 cm × 15 cm)
- Weight: 0.23 kg (0.5 lbs)
- Mounting: Single slot in 1746 chassis with DIN-rail support
- Electrical Isolation: 500V DC (signal); 1500V AC (backplane)
Typical Applications
- Factory automation and assembly line control systems
- HVAC and environmental monitoring systems
- Motor starter interlocks and discrete control logic
- Building automation and legacy system maintenance
- Hazardous location (Class I / Class II) industrial monitoring
Compatibility & Replacements
Compatible With
- SLC 500 programmable logic controllers (all series)
- 1746-class I/O chassis and backplane configurations
- RSLogix 500 programming software
- 1746-HT and 1746-HCA connector blocks
- Industrial systems requiring 100–120V AC discrete inputs
Replaces / Drop-In Replacement For
- Used as direct replacement within SLC 500 I/O slots
- Verify compatibility with your specific chassis configuration
- Module was officially discontinued by Allen-Bradley on August 19, 2018; sourced through secondary channels for legacy system maintenance
Works With
- RSLogix 500 development environment
- SLC 500 programming and configuration tools
- Standard 1746 backplane and rack assemblies
- AC-powered field devices (sensors, switches, solenoids, pilot lights)
