ABB AI845-eA 3BSE023675R2 Analog Input Module

Configured for analog signal acquisition and HART device pass-through in ABB S800 I/O platforms, the ABB AI845-eA 3BSE023675R2 (AI845-eA Analog Input Module) provides direct physical/electrical execution across process control loops. The module interfaces 8 unipolar, single-ended channels for 0-20 mA, 4-20 mA, 0-5 VDC, or 1-5 VDC field signals with 12-bit resolution and a maximum error of 0.1%. Operating in single or redundant topologies, the unit incorporates short-circuit-proof, current-limited power distribution for 2-wire and 3-wire field transmitters.

Suffix Breakdown & Model Matrix

Hardware Specifications

Backplane Bus Communication Velocity & I/O Density Scaling

The module communicates with the central controller across the ModuleBus backplane, preserving signal integrity during real-time scan cycles. The internal interface updates all 8 channels within a 10 ms update cycle, allowing high backplane bus communication velocity across expanded S800 I/O clusters. When deployed alongside high-density I/O configurations, onboard logic routes digital HART diagnostic data without compromising analog loop conversion speeds. Comprehensive diagnostic routines continuously monitor field wiring conditions, transmitter power loop integrity, and internal channel states.

Frequently Asked Questions

Q: How are individual channel input types determined on the AI845-eA module?

A: Channel modes depend on the selected Module Termination Unit (MTU). When paired with TU844 or TU845 MTUs, each channel can be independently set to voltage or current mode. When using standard MTUs like the TU810 or TU830, all channels operate collectively as either voltage inputs or current inputs.

Q: What protection mechanisms prevent damage from field line overvoltage conditions?

A: Each input circuit contains overvoltage and undervoltage protection designed to withstand continuous signal excursions of at least 11 VDC without component degradation. Additionally, integrated transmitter power outputs include current-limiting circuits to protect against field short circuits.

Field Installation Guidelines

Snap the AI845-eA module firmly onto its compatible S800 Module Termination Unit (such as TU810, TU844, or TU845) mounted on a standard 35 mm DIN rail. Ensure all field wiring for 2-wire or 3-wire transmitters is routed through twisted-pair shielded cables, grounding the overall shield drain wire to the dedicated earth busbar at the enclosure entry point. Maintain field cable runs below the maximum allowable limit of 600 m to prevent signal attenuation and noise pickup. Verify that external 24 VDC transmitter power supplies are regulated and routed through appropriate fuse protection before energizing the module.