Overview
The Allen-Bradley 1771-IAD is a Series D discrete digital input module engineered for PLC-5 controller platforms. This 16-input module operates at 120V AC/DC voltage and installs in 1771-A1B, A2B, A3B, A3B1, A4B, 1771-AM1 and AM2 chassis. The module delivers reliable signal processing for industrial automation applications requiring discrete device monitoring such as pushbuttons, limit switches, pilot lights, and motor starter contacts.
Key Features
- Series D module supports ½, 1, and 2-slot I/O addressing
- Sixteen (16) isolated input channels for 120VAC / 125VDC input voltage
- Green module active indicator and 16 red status indicators on front panel for field-side input monitoring
- Adjustable input filtering minimizes false triggering in electrically noisy environments
- Compatible with 1771-WH wiring arm for tool-free module replacement
Technical Specifications
- Operating voltage range: 79–138V AC or 79–138V DC
- Input signal delay: 120V AC/60Hz 5ms (+3ms) or 20ms (+5ms) selectable; 120V DC 3ms (+0.1ms) or 10ms (+1ms) selectable for Off-to-On; 25ms (+5ms) for On-to-Off transition
- Input Count: 16 channels
- Module Series: Series D
- Slot Addressing: ½, 1, and 2-slot I/O
- Compatible Power Sources: Single 120V AC or 125V DC
Typical Applications
- Discrete field device monitoring (proximity switches, pushbuttons, selector switches)
- Relay and contactor status inputs
- Safety interlock signal monitoring
- Motor starter and pilot light control inputs
- Industrial machine control and sequence logic
Compatibility & Replacements
Compatible With
- PLC-5 controller systems and platforms
- 1771 Series I/O chassis (1771-A1B through A4B)
- 1771-AM1 and AM2 universal I/O chassis
- Field devices with off-state leakage current less than 2.8mA
- 1771-WH wiring arm for field connections
Replaces / Drop-In Replacement For
The 1771-IAD Series D replaces earlier Series C versions (1771-IA, 1771-IA2) in many applications. For definitive replacement compatibility with your legacy equipment, verify with your system integrator or controls engineer.
Works With
- PLC-5 programming and runtime environments
- 1771-OAD AC 120V output modules for coordinated I/O control
- 1771-OA output modules (with snubber network)
- Standard discrete control logic and motion control routines
