Allen-Bradley 1771-OW 1771 Selectable Contact Output Module

Description

The Allen-Bradley 1771-OW is a selectable contact output hardware module designed for integration within a 1771 I/O chassis. Functioning as a specialized switching unit, the device provides 8 outputs arranged into 4 isolated groups of 2, with each distinct group configured around its own independent common connection. Every individual output pathway is electrically isolated from the internal module logic circuitry, enabling the system to simultaneously drive separate external loads up to a maximum continuous current of 1.0A per output at rated power. Because the hardware does not contain built-in surge limiting circuitry, the 1771-OW must be utilized for switching resistive loads only, and it is not recommended for inductive or capacitive load setups. Logic control processing and internal relay coil energization paths are fully powered directly through the backplane of the host I/O chassis enclosure.

Features

• Individually selectable output jumper configurations allowing each point to be customized for normally-open (N.O.) or normally-closed (N.C.) operation.
• Four isolated circuit groupings containing two output lines per group to support multi-common wiring distribution.
• Electrical isolation barriers separating field-side output contact switching loops from local backplane logic components.
• Front-mounted diagnostic array consisting of 8 status indicators that illuminate when their corresponding output relay coils are energized.

Applications

• Dedicated switching of resistive control loops in factory production environments.
• Dry contact interface routing to external input modules or low-current logic devices.
• Distributed automation control via multi-group contact isolation setups.

Technical Specifications

Connections/Interfaces

Installation Guidelines

• Backplane Power Safety: Always remove full power from the 1771 I/O chassis backplane and the connected wiring arm before removing or installing any I/O hardware to avoid physical injury or unexpected system operation.
• Electrostatic Discharge Protection: Prior to handling the physical circuit board assembly, touch a grounded object to discharge static buildup, and avoid touching the rear backplane connector pins.
• Chassis Plastic Keying: Mount plastic keying bands onto the chassis backplane tracking points between positions 6 and 8, and between positions 16 and 18 to lock the chosen slot exclusively for this hardware type.
• Module Placement Limits: The module can be installed in any available I/O chassis slot connector except for the leftmost slot position, which is strictly reserved for adapter or processor modules.
• Jumper Configuration Control: To modify factory default normally-open operation, remove the 4 side screws to open the housing covers and manually transition internal jumpers K1, K2, K3, and K4 to their N.C. positions.
• Interconnect Cable Length: Restrict total field wiring interconnect runs to a maximum boundary length of 1000 feet (304.8 meters).
• Parallel Loading Warning: Do not hook up two or more outputs in parallel in an attempt to exceed the continuous 1A power rating, as minor deviations in individual relay response times can cause a single contact to bear the entire load current.