Allen-Bradley 1771-OFE1 PLC-5 Analog Output Module

Description

The Allen-Bradley 1771-OFE1 is a 4-channel analog output module that converts digital values from a processor into analog voltage signals to control field devices within a industrial control network. This single-slot module interfaces directly into a Bulletin 1771 I/O chassis and operates with PLC-5 controllers via block transfer programming. The module converts 12-bit binary or 4-digit binary-coded decimal (BCD) values into high-resolution voltage outputs to regulate modulating infrastructure such as control valves, adjustable frequency AC drives, dampers, louvers, and positioners. It also acts as a precise signal source for data loggers, splitters, panel meters, totalizers, and single-loop controllers. Featuring 1500V optoelectrical isolation and 1000V individually-isolated differential outputs, the device secures processing equipment against localized overvoltage situations and contains dedicated internal short-circuit overload protection on each loop.

Features

• Seamless operational configuration utilizing block transfer programming with Write Block Transfer instructions moving up to 13 data words and Read Block Transfer instructions carrying 5 debugging words.
• Four independent, 1000V individually-isolated differential voltage loops avoiding ground loops across widely separated field components.
• Dual data format functionality supporting both Binary Coded Decimal (BCD) scaling and natural binary encoding to fit specific system setups.
• Self-testing logic sequences executed automatically during startup to provide early operational diagnosis and system verification.
• Built-in overload protection circuits embedded on each separate channel path to safeguard hardware against load short circuits.
• Shipped with a dedicated 1771-WH wiring arm allowing rapid module replacement without disconnecting active field wiring links.

Applications

• Proportional modulation of industrial control valves and dampening louvers.
• Speed command reference transmission for adjustable frequency AC variable speed motor controllers.
• Signal sourcing for centralized data logging networks, splitters, and digital panel meters.
• Distributed control coupling with standalone single-loop controllers and processing totalizers.

Revisions

Technical Specifications

Performance and Electrical Specifications

Mechanical and Environmental Specifications

Installation Guidelines

• Disconnect all chassis backplane power before inserting or removing the module from its structural slot.
• Snap appropriate keying bands between positions 10-12 and 26-28 to dedicate the specific slot position for this module type.
• Slide the card firmly into the chassis card guides until it seats fully into the backplane connectors.
• Secure all external loop wires to the 1771-WH wiring arm, ensuring correct polarity for each isolated channel.
• Sum the backplane current draw (1.50 A) with all other modules to confirm the chassis power supply capacity is not exceeded.