ABB AO845A (3BSE045584R1) S800 Analog Output Module Overview

Brand Background

ABB is a global technology leader in electrification, robotics, automation, and motion systems. Within process automation, ABB’s System 800xA and Compact Product Suite utilize the S800 I/O system, a comprehensive, distributed process I/O platform designed to deliver continuous uptime, high signal density, and flexible system architecture across heavy continuous-process operations.

Model Overview: AO845A (Part Number: 3BSE045584R1)

The ABB AO845A (Part Number: 3BSE045584R1) is an 8-channel Redundant Analog Output Module with HART communications support. Belonging to the S800 I/O product line, the module is designed for applications requiring high availability and precise signal actuation.

The AO845A converts digital control commands into 8 isolated 0/4–20 mA analog output current signals. It supports both single and dual-redundant configurations, allowing hot-swapping and seamless fault transfer without interrupting analog output signals to critical field devices.

ABB AO845A 3BSE045584R1 S800 I/O

Key Technical Specifications and Parameters

• Manufacturer: ABB

• Series: S800 I/O System

• Model Designation: AO845A

• Part / Catalog Number: 3BSE045584R1

• Product Type: 8-Channel Redundant Analog Output Module with HART

• Number of Channels: 8 analog output channels

• Output Signal Range: 0 to 20 mA or 4 to 20 mA

• Digital Resolution: 12-bit

• Maximum Load Resistance ($R_{L\text{max}}$): $750\ \Omega$

• HART Protocol Support: HART pass-through communication for smart field instrument diagnostics and remote configuration

• Redundancy & Hot-Swapping: Supports 1:1 redundant pairing (single or redundant deployment) and online module replacement (Hot Swap)

• Loop Supervision: Integrated loop-supervised digital input function for open-circuit and line fault detection

• Compatible Termination Units: TU810, TU812, TU814, TU830, TU833, TU842, TU843, TU852

• Dimensions & Weight: 119 mm (H) x 45 mm (W) x 102 mm (D); Net Weight approx. 0.20 kg

Operating Industries

The ABB AO845A module is deployed across high-availability and safety-critical process industries using System 800xA or AC 800M automation platforms:

• Oil, Gas & Petrochemicals: Offshore extraction platforms, gas processing facilities, pipelines, and continuous refining operations.

• Power Generation & Utilities: Thermal, combined-cycle, nuclear, and hydroelectric power plants.

• Chemical & Pharmaceutical Processing: Continuous reaction lines, batch processing, and fine chemical formulation facilities.

• Pulp & Paper: Chemical recovery boilers, paper machines, and continuous pulping operations.

• Metals & Mining: Smelters, continuous casters, and mineral processing lines.

• Water & Wastewater: Large-scale municipal water purification facilities and industrial fluid networks.

Common Usage Scenarios

1. Redundant Valve & Actuator Positioning

   Driving 4–20 mA electropneumatic control valves and positioners in critical loops where signal loss could cause plant shutdown or safety hazards.

2. HART Smart Field Device Integration

   Enabling two-way digital communication between host DCS software and smart field positioners for remote calibration, valve stroke testing, and diagnostic monitoring.

3. Speed Reference Setpoint Distribution

   Sending analog reference signals to variable frequency drives (VFDs) and motorized control drives in high-availability pumping or fan systems.

4. Hot-Swappable High-Availability Control Racks

   Operating in dual-redundant pairs on TU842 or TU843 Module Termination Units (MTUs) to permit online module servicing without losing signal continuity to the field process.