Product Overview
The Allen-Bradley 1771-IAN is a PLC-5 Digital AC/DC Input Module engineered to convert AC or DC signals from field devices into the logic levels required by the processor. This module directly controls the state of corresponding bits in the PLC data table, enabling seamless integration of pushbuttons, limit switches, pilot lights, motor starters, and annunciators. With its modular, space-saving design, the 1771-IAN adds input capacity to a PLC-5 control system efficiently and cost-effectively.
Designed for reliability, the 1771-IAN includes a 1771-WN wiring arm that allows module replacement without disconnecting field wiring, reducing downtime. It supports ½-slot and 1-slot I/O addressing and features 32 red status indicators on the front panel for quick diagnostics. Optoelectrical isolation protects system circuits from electrical transients, while an input filtering feature minimizes electrical noise.
Key Features & Benefits
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32 Inputs (4 Sets of 8): High-density input capacity in a compact form factor.
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120V AC/DC Voltage Category: Compatible with common industrial voltage levels.
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AC Operating Voltage 85–138V: Wide tolerance ensures stable operation.
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Backplane Current 280mA: Low power consumption reduces system load.
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Fast Signal Delays: 10ms (±7) on-delay and 20ms (±15) off-delay for AC signals.
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Optoelectrical Isolation: Protects against electrical transients.
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Input Filtering: Suppresses electrical noise for reliable readings.
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Hot-Swap Capable via 1771-WN Wiring Arm: Minimizes downtime during maintenance.
Technical Specifications
| Parameter |
Value |
| Manufacturer |
Rockwell Automation |
| Brand |
Allen-Bradley |
| Part Number |
1771-IAN |
| Module Type |
Digital AC/DC Input Module |
| Number of Inputs |
32 (4 sets of 8) |
| Voltage Category |
120 Volts AC/DC |
| AC Operating Voltage |
85–138 Volts |
| DC Operating Voltage |
N/A |
| Backplane Current |
280 Milliamperes |
| Max AC Off-State Current |
3.0 Milliamperes |
| Max DC Off-State Current |
0.8 Milliamperes |
| Typical AC Signal Delay (On) |
10 (+/- 7) ms |
| Typical DC Signal Delay (On) |
N/A |
| Typical AC Signal Delay (Off) |
20 (+/- 15) ms |
| Typical DC Signal Delay (Off) |
N/A |
| Wiring Arm |
1771-WN |
| Dimensions |
3.5 x 6.5 x 2.0 in (89 x 165 x 51 mm) |
| UPC |
10612598117267 |
Industry Applications
The 1771-IAN is ideal for manufacturing, material handling, and process control applications where reliable discrete input sensing is essential. For example, in an automotive assembly line, the module monitors presence sensors and limit switches, ensuring precise positioning of robotic arms. In a packaging plant, it interfaces with photo-eyes and proximity sensors to track product flow, triggering downstream equipment. In a water treatment facility, the 1771-IAN reads level switches and flow indicators, providing critical status to the PLC-5 controller.
Installation & Setup Guidance
Install the 1771-IAN into any 1771 I/O chassis that contains a PLC-5 processor. Before insertion, ensure the chassis power is off. Align the module with the guide rails and slide it in until it seats firmly. Attach the 1771-WN wiring arm, which simplifies field wiring and allows future replacement without disconnecting wires. Use the keying bands to prevent improper installation: place them between pins 20 and 22 on the upper connector and between pins 16 and 18 on the lower connector. After wiring, power up and verify that the 32 red status indicators reflect the correct input states.
Maintenance & Reliability
Routine inspection of the 1771-IAN ensures long-term reliability. Periodically check for dust accumulation on the front panel and connectors, and clean with dry compressed air if needed. Verify that all wiring connections remain tight. The module’s optoelectrical isolation and input filtering reduce the risk of damage from transients and noise, contributing to extended service life. Because the wiring arm allows quick replacement, mean time to repair is minimized, reducing costly downtime.
Compatibility & Integration
The 1771-IAN is designed for the PLC-5 family and installs into a 1771 I/O chassis. It supports ½-slot and 1-slot I/O addressing, making it flexible for various system configurations. The module works with any PLC-5 processor that accepts 1771 I/O modules. No special communication protocols are required—the module interfaces directly with the backplane.
Selection Guide & Purchasing Advice
Before purchasing, verify that your system uses a 1771 I/O chassis and a PLC-5 processor. Confirm the input voltage category (120V AC/DC) matches your field devices. Check the backplane current budget to ensure the 280mA load is within your power supply capacity. The 1771-IAN is available from PLC Source PRO, a trusted supplier of industrial automation parts. Ensure you order the correct part number to guarantee compatibility.