Product Overview

• Model: AI845
• Part No: 3BSE023675R1
• Brand: ABB
• Series: S800 Distributed I/O System
• Type: Analog Input Module

• Function: It serves as the analog signal acquisition unit of S800 I/O station. It collects standard current and voltage signals from pressure, flow, level and temperature transmitters on site, converts analog signals into digital data and uploads them to AC800M controller for PID regulation, parameter display and logic interlock. It can supply power to two-wire transmitters with current limiting protection, and realizes HART protocol transparent transmission to read extended parameters and diagnostic information of smart instruments. It supports standalone operation or redundant hot backup configuration to improve system reliability.

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Core Features

• 8 unipolar single-ended input channels, when matched with TU844/TU845 terminal base, each channel can be flexibly set as current or voltage input
• 12-bit A/D conversion resolution, maximum basic error within 0.1%, stable signal acquisition accuracy
• Built-in HART communication channel, directly accesses HART smart transmitter without additional signal isolation equipment
• Each channel outputs limited power for field transmitters, with overcurrent protection to prevent damage from short-circuit wiring
• Group isolation between 8 channels and system ground, effectively suppress ground loop interference from long-distance field wiring
• Complete channel fault diagnosis including open circuit, over-range and under-range alarm, front panel LED indicates module running and fault status
• PCB with conformal coating, dustproof, moisture-proof and anti-electromagnetic interference, adapting to long-term cabinet operation

• Supports hot swapping under redundant power supply, no need to shut down the whole station during on-site replacement and maintenance

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Technical Specifications

• Supported signals: 0~20mA, 4~20mA DC; 0~5V, 1~5V DC
• Input impedance: Voltage input ≥10MΩ, current input fixed 250Ω
• Working power: 24VDC ±10%, typical power consumption 3.5W
• Operating temperature: -25℃ ~ +70℃
• Storage temperature: -40℃ ~ +85℃
• Overall dimension: 119mm × 45mm × 102mm
• Net weight: 0.23kg
• HS Code: 85389091
• Certifications: CE, UL, RoHS

• Supply status: Mass production available, brand new original sealed goods and fully tested refurbished spare parts in stock

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Compatibility

• Applicable control system: ABB System 800xA DCS, AC800M PLC controller, Freelance DCS
• Matching terminal bases: TU810, TU812, TU814, TU844, TU845 and other S800 series MTU termination units
• Installation method: Snap-on DIN rail mounting, cascaded with other S800 I/O modules via ModuleBus backplane

• Redundancy scheme: Two AI845 modules paired with redundant terminal base to implement dual redundant input

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Application

• Process signal collection for petrochemical, chemical and oil & gas production DCS control loops
• Boiler, turbine and auxiliary system parameter acquisition in thermal power plant control cabinets
• Automatic monitoring of flue gas desulfurization, denitrification and wastewater treatment environmental protection equipment
• I/O expansion and aging module replacement for existing ABB 800xA and Freelance automation control systems