AI845 3BSE023675R1 ABB S800 I/O Redundant Analog Input Module In Stock

AI845 3BSE023675R1 ABB S800 I/O Analog Input Module Overview

The ABB AI845 is a high-availability 8-channel analog input module engineered for the S800 I/O system family. Designed for high-reliability process control, the AI845 supports both single and dual-redundant configurations with full HART pass-through communication capability. Each unipolar input channel acquires standard field signals including 0...20 mA, 4...20 mA, 0...5 V, and 1...5 V d.c. Integrated transmitter power supply control simplifies cabling by feeding 2-wire or 3-wire field transmitters directly from the termination unit.

Technical Specifications

• Brand & Series: ABB S800 I/O
• Model & Part Number: AI845 / 3BSE023675R1
• Channel Architecture: 8 single-ended unipolar channels, groupwise isolated from system earth
• Input Measurement Ranges: 0...20 mA, 4...20 mA, 0...5 V, 1...5 V d.c.
• Analog Resolution & Accuracy: 12 Bit resolution with max total error of 0.1%
• Input Impedance: Greater than 10 MΩ (Voltage mode); 250 Ω nominal (Current mode)
• Signal Conversion Dynamics: 10 ms update cycle time with 290 ms filter rise time (0-90%)
• Temperature Coefficient: Maximum temperature drift of 50 ppm/°C
• Interference Rejection: Normal Mode Rejection Ratio (NMRR) greater than 40 dB at 50/60 Hz
• Overvoltage & Insulation: 11 V d.c. non-destructive overvoltage withstand; 50 V rated insulation with 500 V a.c. dielectric test level
• Module Backplane Power Demand: 100 mA at +5 V d.c. Modulebus; 50 mA at +24 V d.c. Modulebus
• External Supply Demand: Max 265 mA at +24 V d.c. (22 mA base + transmitter current load x 1.32)

Suitable Equipment and Application Scenarios

Engineers specify the ABB AI845 module for continuous process plants where unexpected I/O channel loss results in costly downtime. Typical equipment integrations include:

• Fault-Tolerant DCS Loops: Paired with redundant controller bases in oil refineries, chemical reactors, and gas compression stations.
• HART Field Device Networks: Interfacing smart pressure, flow, and temperature transmitters requiring bi-directional digital parameter passing to central asset management software.
• Power Generation Turbines: Monitoring critical 1...5 V and 4...20 mA feedback signals from hydraulic actuators and throttle valve positioners.
• Remote Pump Stations: Supplying dedicated current-limited loop power to 2-wire transmitters over long field cabling runs up to 600 meters.

Installation Guide

Mount the AI845 onto compatible Module Termination Units using keying code CC to prevent cross-module insertion errors. Engage the dual retention clips to seat internal backplane pins into the Modulebus. For channel-by-channel mixed voltage and current operation, wire the module to a TU844 or TU845 MTU. Ensure field wiring shielding grounds tie back to designated busbars to maintain G3 ISA-S71.04 corrosion tolerance in harsh environments.

Advanced Diagnostic Capabilities

The AI845 contains real-time supervisory circuits covering internal, external, and channel-level operations. Front-facing LEDs display Fault (F), Run (R), and Warning (W) conditions.

• Internal System Checks: Real-time monitoring of analog read-back circuitry, reference voltages, internal power rails, memory checksums, and watchdog timers.
• Multiplexer & Filter Health: On-board diagnostics sweep internal low-pass filters, input multiplexers, and dedicated test channels continuously.
• External Field Fault Handling: Immediate detection of external power supply dropouts, transmitter power overcurrent conditions, and external shunt resistor errors.

Compatibility Matrix

The AI845 supports flexible integration across the standard S800 termination family:

• Redundant Base Units: TU844, TU845, TU854
• Simplex Base Units: TU810, TU810V1, TU812, TU814, TU818, TU830, TU833, TU835, TU838
• Protocol Compatibility: Native HART pass-through across standard 4...20 mA loops

Certifications and Industrial Standards

The ABB AI845 complies with severe industrial environmental specifications. Electrical safety ratings include EN 61010-1 and UL 61010-2-201. Hazardous location approvals cover Class 1 Division 2 cULus, Class 1 Zone 2 cULus, and ATEX Zone 2. Marine installation approval covers Bureau Veritas (BV), Det Norske Veritas (DNV), and Lloyd's Register (LR). Industrial EMC compliance covers EN 61000-6-2 immunity and EN 61000-6-4 emissions.

Packaging, Warranty, and Express Logistics

• Included Packaging: 1 x Factory-Sealed ABB AI845 Analog Input Module (Article 3BSE023675R1)
• Warranty Terms: Covered by a comprehensive 12-Month replacement warranty against hardware defects
• Shipping Expediting: Dispatched within 24 to 48 hours via premium express couriers including FedEx, UPS, and DHL for global site delivery

Global PLC Spare HUB's Insight

When upgrading standard S800 racks to redundant configurations, system integrators often miss the MTU dependency of the AI845. While the module installs physically onto a basic TU810 MTU, achieving dual-module hardware redundancy requires pairing two AI845 modules on a TU844 or TU845 base. Furthermore, using non-redundant MTUs forces all 8 channels to share the same input signal type (all current or all voltage), whereas the TU844/TU845 termination units enable independent per-channel signal selection. Verifying your target MTU part number prior to commissioning prevents unexpected hardware re-wiring.

Selection Guide and Engineering FAQ

Selection Tip: Choose the AI845 when your control system demands process redundancy or direct HART transmitter power distribution without extra terminal blocks. For basic non-redundant installations without HART pass-through requirements, evaluate standard non-redundant S800 analog modules.

Question: How does the AI845 handle transmitter short-circuit conditions in the field?

Answer: Each channel features individual current-limiting circuitry on the external transmitter power output. If a field cable shorts, the module limits loop current, flags an external channel error, and prevents the fault from pulling down the main 24 V d.c. field supply rail.

Question: Can I read 0...5 V pressure transducers and 4...20 mA flow meters on the same module?

Answer: Yes, provided the module is mounted on a TU844 or TU845 MTU. These specific termination units enable individual channel switching between voltage and current input modes.

Question: What is the primary operational difference between the AI845 and standard analog input units like the AI810?

Answer: The AI845 supports dual-module hardware redundancy, HART pass-through communications, higher power dissipation capability (3.5 W vs 1.5 W), and comprehensive channel-level test diagnostics missing in basic modules.

Question: Does a HART hand-held communicator or asset management software require special modem taps on the module?

Answer: No, the module incorporates native HART pass-through circuitry. Superimposed FSK HART signals travel through the internal analog conversion paths to the controller Modulebus without interfering with the 4-20 mA primary process variable.

Question: How does temperature affect module installation inside compact control cabinets?

Answer: The module operates at ambient temperatures up to +55 °C under horizontal DIN-rail mounting. When mounted vertically inside compact MTUs, the maximum allowable ambient operating temperature scales down to +40 °C to maintain proper internal convection cooling.

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