Allen-Bradley 1791-0A16 AC Output Block I/O Module Overview

Product Introduction

When upgrading or maintaining legacy industrial control systems, the Allen-Bradley 1791-0A16 provides a reliable AC output solution. This Block I/O module belongs to the 1791 series and delivers sixteen AC output channels. It is designed to energize devices such as pilot lamps, buzzers, sirens, relays, and contactors. The module operates with signal voltages from 20 to 132 VAC and supports frequencies of 47 to 63 Hz. Its compact form factor minimizes panel space, making it suitable for distributed I/O applications near electrical loads.

Technical Specifications

The 1791-0A16 features sixteen outputs grouped into two groups of eight channels each. The operating voltage range is 20-132 VAC, and the output voltage range matches this at 20-132 VAC. External power required is 85-132 VAC. The module is compatible with PLC-2, PLC-3, PLC-5/20, and PLC-5 controllers. It supports both vertical and horizontal mounting orientations. Output delay times are frequency-dependent: off-to-on transition takes 1.0 ms at both 50 Hz and 60 Hz, while on-to-off transition takes 8.3 ms at 60 Hz or 10.0 ms at 50 Hz. Off-state leakage current is 3 mA, and maximum on-state current is 50 mA per output. Surge current rating is 10 A for 50 ms, repeatable every 2 seconds.

Industry Applications

This module excels in discrete manufacturing environments where AC loads require reliable switching. For example, in a packaging line, the 1791-0A16 can control multiple AC-powered solenoids and indicator lights. Its distributed design reduces long cable runs, lowering installation costs. In material handling systems, the module's 20-132 VAC range accommodates various AC devices, from small pilot lamps to larger contactors. The two-group isolation (1250 VAC between groups) enhances system reliability by preventing fault propagation.

Installation & Setup Guidance

Mount the 1791-0A16 vertically or horizontally using the provided slots. Use 14 AWG stranded wire with maximum insulation thickness of 3/64 inches for signal connections. The removable terminal strip simplifies wiring and module replacement. Before connecting loads, verify that the external power supply delivers 85-132 VAC and that the total continuous current does not exceed 150 mA. Ensure the scanner/processor, number of blocks, throughput requirements, total installation distance, and transmission rate are considered during system design. Status indicators on the module aid in troubleshooting.

Compatibility & Integration

The 1791-0A16 integrates with legacy Allen-Bradley PLC-2, PLC-3, PLC-5/20, and PLC-5 programmable controllers. It functions as a distributed I/O block, reducing wiring complexity by placing I/O near field devices. The module uses remote I/O (RIO) communication, with power supply to RIO isolation rated at 500 VAC. For systems requiring expansion, multiple 1791 blocks can be daisy-chained. Always verify scanner compatibility and maximum block count per network segment before installation.

Selection Guide & Purchasing Advice

Before purchasing the 1791-0A16, confirm that your controller supports 1791 Block I/O modules. Verify the required output voltage and current match your load specifications. The module is best suited for AC loads up to 50 mA per channel. For higher current requirements, use external relays or contactors. BluePLC Industrial offers this module with verified stock and fast shipping. Contact our team for current lifecycle status and availability. We recommend ordering a spare module for critical systems to minimize downtime.