Allen-Bradley 1791-16A0 Block I/O Module: 16 Inputs, 120VAC

Product Overview

When your automation system requires reliable, distributed input handling, the Allen-Bradley 1791-16A0 Block I/O module delivers a compact and self-contained solution. This module integrates 16 discrete inputs rated for 120VAC, organized into 2 groups of 8 for flexible wiring and system design. As part of the 1791 Block I/O series, it combines power supply, I/O rack, adapter, and input functions into a single unit, simplifying installation and reducing panel space. The 1791-16A0 is engineered for industrial environments where dependable signal acquisition from field devices is critical.

Technical Specifications

The 1791-16A0 operates with an external power supply of 85-132VAC at 47-63 Hz. Its on-state voltage range is 79-132VAC at the same frequency, with a nominal input voltage of 120VAC. The module draws 150 mA from the external power source. Key input characteristics include:

On-state voltage range: 79-132VAC, 47-63 Hz

External power: 85-132VAC, 47-63 Hz

Input on-state voltage range: 79-132VAC

Maximum off-state voltage: 35VAC

Input on-state current: 5 mA at 79V minimum

Input off-state current: 2.3 mA minimum

Maximum surge current: 10A for 50 ms (repeatable every 2 seconds)

Maximum output rating: 600 mA at 30°C; 300 mA at 60°C

These parameters ensure consistent performance across typical industrial line voltages and frequencies.

Industry Applications

The 1791-16A0 is well-suited for discrete manufacturing, material handling, and packaging lines where distributed I/O reduces wiring costs and simplifies troubleshooting. Common field instruments include proximity switches, limit switches, selector switches, float switches, and pushbutton switches. For example, in a conveyor system, the module can monitor multiple limit switches to detect product position and trigger sorting actions. Its 2-group configuration allows separate commons for different machine zones, enhancing diagnostic isolation.

Installation & Setup Guidance

Mount the 1791-16A0 either horizontally or vertically using the integrated mounting holes. Ensure at least 2 inches (58.0 cm) of clearance on all sides for proper ventilation. Connect external power (85-132VAC, 47-63 Hz) to the designated terminals. Wire field devices to the input channels, respecting the 2 groups of 8 inputs. Use compatible 1771 series output modules only if their off-state leakage current is less than the 1791-16A0's minimum off-state current (2.3 mA). Verify that the minimum on-state voltage of the block I/O exceeds the supply voltage minus the on-state voltage drop across the output module.

Maintenance & Reliability

Routine inspection of the 1791-16A0 should focus on verifying input signal integrity and checking for loose connections. The module's robust design supports operation up to 60°C, making it suitable for warm factory environments. Periodically clean the enclosure with a dry cloth to prevent dust buildup that could impede airflow. No internal adjustments are required; the module is a sealed unit. For extended service life, ensure the external power supply remains within the specified 85-132VAC range.

Selection Guide & Purchasing Advice

Before ordering the 1791-16A0, confirm that your system requires 16 discrete 120VAC inputs organized in 2 groups. Verify compatibility with your controller's scanner and network topology (daisy-chain configuration). The module weighs 1.25 lbs (0.57 kg) and ships with standard documentation. For complete technical specifications and current availability, contact BluePLC Industrial. Our team can assist with cross-references and ensure the 1791-16A0 meets your application needs.