Allen-Bradley 1791-0B16 - 16-Channel DC Output Block I/O Module

Expand your control system easily with the Allen-Bradley 1791-0B16. This is a compact, self-contained Block I/O module that provides 16 discrete DC output channels for remote I/O applications. It integrates the controller interface, power supply, and I/O terminals into one rugged block, making it a cost-effective solution for distributing outputs near field devices in packaging, material handling, and machine control panels. It connects via Universal Remote I/O to compatible Allen-Bradley PLCs.

Complete Technical Specifications

Brand & Series: Allen-Bradley 1791 Block I/O (Series B)

Full Model Number: 1791-0B16

Module Type: 16-Point DC Sourcing Output Block

Output Configuration: 16 points, sourcing

Output Current: 500 mA per point @ 60°C (vertical mount), 250 mA @ 60°C (horizontal mount)

Load Voltage Range: 10V to 30V DC

External Power Supply: 19.2V to 30V DC

Switching Speed: Turn-ON delay: 0.5 ms max, Turn-OFF delay: 1.0 ms max

Communication Protocol: Universal Remote I/O (compatible with PLC-5, SLC 5/02, etc.)

Status Indicators: 1 COMM (communication), 1 STATUS (module), 16 I/O (per point) LEDs

Configuration: Dual rotary switches for setting Rack Number, Starting Group, Baud Rate, and Last Chassis/State.

Terminals: Removable terminal blocks for easy maintenance.

Wire Size: 2 mm² (14 AWG) solid wire recommended, max 3/64 in. insulation.

Dimensions (H x W x D): Approx. 6.95 in. x 2.7 in. x 3.85 in.

Weight: 1.00 lb (0.45 kg)

Installation & Wiring Guide

For best performance, mount the 1791-0B16 vertically. Connect the external 24V DC power (19.2-30V) to the designated terminals. Wire your field devices (solenoids, indicators) between the output terminals and the DC common. Use the rotary switches to set a unique Rack Number and configure the communication rate to match your scanner. If this is the last module in a chain, install the required termination resistor. The built-in LEDs will show communication health and output status.

Package & Warranty

What's Included: 1 x Allen-Bradley 1791-0B16 Output Block I/O Module.

Our Guarantee: This product is covered by a reliable 12-month warranty.

Fast Shipping Service

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Frequently Asked Questions (FAQ)

What is Universal Remote I/O?

It is an older, proprietary Allen-Bradley serial communication protocol used to connect remote I/O blocks (like the 1791 series) to controllers such as the PLC-5 and SLC 5/02. It is not Ethernet/IP or DeviceNet.

Why is vertical mounting recommended?

Vertical mounting provides better heat dissipation, allowing the outputs to handle the higher current rating of 500 mA per point. Horizontal mounting reduces the allowable current to 250 mA per point due to cooling constraints.

How is the module addressed on the network?

You set the module's address using the two rotary switches on its side. These set the Rack Number (0-37 octal) and the Starting Group within the rack's I/O image.

What does the "Last Chassis/State" switch do?

If this module is the last one in a physical daisy-chain, you set this switch to "Last". This configures the module's communication driver correctly for end-of-line termination.

Can I connect it to a modern CompactLogix or ControlLogix?

Not directly. Modern Logix controllers use EtherNet/IP or other networks. To use this module, you would need a bridging communication module (like a 1785-BCM) in a PLC-5 or SLC chassis to translate between the networks.

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