Overview
The Allen-Bradley 1794-IA8 is an 8-point AC digital input module from the FLEX I/O series, engineered for monitoring 120V AC signals in distributed control systems. This compact, modular module converts AC input signals to logic levels suitable for processor integration, offering straightforward installation on standard DIN-rail or panel-mounted configurations.
Key Features
- 8 non-isolated digital inputs with individual status indicators (yellow LEDs)
- Voltage range: 65–132V AC; nominal 120V AC at 47–63 Hz
- High signal integrity with 2150V DC isolation (field to system)
- Input current ratings: 7.1 mA (min on-state), 14.32 mA (max on-state)
- Configurable input filter time (12 ms default, field-adjustable)
- Compliant with UL, CSA, CE, and hazardous location approvals (Class 1, Div 2)
Technical Specifications
- I/O Count: 8 digital inputs
- Input Voltage: 65–132V AC (nominal 120V AC)
- Operating Frequency: 47–63 Hz
- On-State Current: 7.1 mA minimum, 14.32 mA maximum
- Off-State Current: 2.9 mA minimum
- Off-State Voltage: 43V AC maximum
- Field-to-System Isolation: 2150V DC
- Power Dissipation: 4.5 W at 132V AC
- Operating Temperature: −4 to 131°F (−20 to 55°C)
- Storage Temperature: −40 to 185°F (−40 to 85°C)
- Dimensions: 94 × 94 × 69 mm (3.7 × 3.7 × 2.7 in.)
- Mounting: DIN-rail or panel mount
- Enclosure Type: Open-style, IP 20
- Terminal Base Compatibility: 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3K, 1794-TB3SK, 1794-TBN, 1794-TBNK
- Wire Compatibility: 22–12 AWG stranded copper
- Certifications: UL, CSA, CE, GOST, KC, Marine
Typical Applications
- Distributed I/O systems requiring AC sensor monitoring (limit switches, indicator lamps, solenoid feedback)
- Process automation plants with legacy or mixed voltage control environments
- Safety function monitoring in non-hazardous industrial settings
- Cabinet and field-mounted remote I/O racks
- Integration with ControlLogix and CompactLogix systems via DeviceNet, ControlNet, or Ethernet/IP adapters
Compatibility & Replacements
The 1794-IA8 is part of Allen-Bradley’s FLEX I/O distributed I/O architecture and mounts directly on 1794 series terminal base units. It works seamlessly with DeviceNet, ControlNet, Profibus DP, and EtherNet/IP adapters, making it suitable for integration into existing Allen-Bradley control systems. Related modules in the FLEX I/O series include the 1794-IA16 (16-point AC digital input) and 1794-IA8I (isolated variant). Input filter time is configurable in RS Logix and Studio 5000 environments for customized debounce settings.
