Overview
The Allen-Bradley 1771-IAD is a 16-point digital input module designed for PLC-5 control systems. This module is a discrete input module that accepts AC and DC signal voltages such as 120VAC with frequency of 50/60 Hz and 125VDC. This Series D revision offers proven reliability across industrial applications and integrates seamlessly into existing 1771 chassis infrastructure.
Key Features
- Sixteen (16) input channels compatible for 120VAC / 125VDC input voltage
- Operating Voltage: 79…138V AC, 79…138V DC
- Interfaces discrete devices such as pushbuttons, switches of different varieties, auxiliary contacts from relays, contactors and other devices
- Signal indicator lights on the front panel which allow you to easily monitor all processes – one green module active indicator, and 16 red status indicators
- Uses a field wiring arm of 1771-WH which is comparable to removable terminal blocks, simplifying installation and maintenance
- Adjustable input signal delay with selectable response time
Technical Specifications
- Input current: 9.9 milliampere at 120V AC 60Hz; 8.7 milliamperes at 120V AC 50Hz; 2.56 milliamperes at 125V DC
- Power dissipation: maximum 8.8 watts, minimum 1.0 watts
- Backplane current requirement: 195 milliamperes
- Signal delay: 120V ac/60Hz: 5ms (±3ms) or 20ms (±5ms) selectable; 120V dc: 3ms (±0.1ms) or 10ms (±1ms) selectable for Off to On transition; 25ms (±5ms) for 120V ac or dc for ON to OFF transition
- Requires keying position between 10 and 12 or between 14 and 16
- Module Type: Series D
- Addressing: Supports ½, 1, and 2-slot I/O addressing
Typical Applications
The 1771-IAD is primarily used to interface discrete devices such as pushbuttons, switches of different varieties, auxiliary contacts from relays, contactors and other devices. Suitable for:
- Machine automation and process control
- HVAC and facility management systems
- Packaging and conveyor line control
- Safety interlocking and emergency stop circuits
- Status monitoring and equipment state sensing
Compatibility & Replacements
Compatible With
- 1771-A1B, A2B, A3B, A3B1, A4B chassis
- 1771-AM1 and AM2 universal I/O chassis
- ControlNet, Remote I/O and Extended Local I/O networks
- PLC-5 processors running RSLogix 5
Replaces / Drop-In Replacement For
- Allen-Bradley 1771-IAD (all revisions A, B, C, D)
- Direct replacement for existing 1771-IAD modules in functioning PLC-5 systems
Works With
- RSLogix 5 programming software
- PLC-5 controller series (5/10, 5/11, 5/15, 5/20, etc.)
- 1771-WH field wiring arm (included or available separately)
- ControlNet and Remote I/O communication networks












