ABB AI845 3BSE023675R1 Analog Input Module

The AI845 is a high-performance, highly reliable analog input module within the ABB Compact Product Suite, designed for analog signal acquisition and processing in industrial automation control systems. This module is configured for single or redundant applications and features 8 independent analog input channels, supporting both current (0...20 mA, 4...20 mA) and voltage (0...5 V, 1...5 V) signal types, providing users with a flexible signal interfacing solution.

The AI845 module integrates advanced diagnostic functions, HART communication support, and high-precision signal conversion capabilities, making it suitable for various industrial environments such as process control, manufacturing, and energy management. Its modular design, excellent compatibility, and strong anti-interference capabilities make it an ideal choice for building reliable automation systems.

II. Product Features and Advantages

1. Multi-Channel Flexible Configuration

• Provides 8 single-ended unipolar input channels.

• Supports mixed input of current and voltage signals (requires specific MTUs such as TU844/TU845/TU854).

• Can be uniformly configured as all voltage or all current inputs on other MTUs.

2. High Precision and High Resolution

• 12-bit analog-to-digital conversion resolution ensures accurate signal acquisition.

• Maximum error does not exceed 0.1%, offering excellent measurement stability.

• Low temperature drift of 50 ppm/°C, suitable for wide-temperature operating environments.

3. Powerful Diagnostics and Monitoring Functions

• Module features built-in self-diagnostic system for real-time monitoring of:

• Module-level errors: Analog readback, reference voltage, internal power supply, checksum, watchdog, memory, etc.

• Internal channel errors: Low-pass filter, multiplexer, test channels, etc.

• External channel errors: External power supply, transmitter power, external shunt, etc.

• Front panel equipped with tri-color LED status indicators: F (Fault), R (Run), W (Warning).

4. HART Communication Support

• Supports HART protocol pass-through communication for direct communication with smart transmitters.

• Provides isolated, HART-compatible power supply per channel, simplifying wiring for 2-wire or 3-wire transmitters.

5. High Reliability and Isolation Protection

• All 8 channels are group-isolated, providing good anti-interference capability.

• Input withstand voltage up to 11 V DC, with overvoltage and undervoltage protection.

• Supports redundant configuration to enhance system availability.

6. Wide Compatibility

• Compatible with various Module Termination Units (MTUs), including compact and extended types, suitable for different installation scenarios.

• Compatible with DIN rail mounting, compact structure, easy to integrate.

III. Application Scenarios

The AI845 module is suitable for various industrial automation applications, particularly excelling in systems with high requirements for signal acquisition reliability, precision, and real-time performance:

1. Process Control

• Monitoring of process variables such as temperature, pressure, flow, and level.

• Analog signal acquisition in chemical, oil, and gas industries.

2. Manufacturing Automation

• Sensor signal reception and processing on production lines.

• Analog monitoring for motor control, position feedback, etc.

3. Energy Management

• Current and voltage monitoring in power systems.

• Energy distribution and load management.

4. Environmental Monitoring

• Analog signal input in environmental protection equipment such as water quality monitoring and gas detection.

5. Redundant Control Systems

• In systems requiring high availability, the AI845 supports redundant configuration to ensure continuous operation.

IV. System Integration and Wiring Instructions

The AI845 can be used with various Module Termination Units (MTUs) to adapt to different wiring and installation needs:

1. MTU Type Overview

• Compact MTUs: Such as TU810, TU812, TU814, TU818, suitable for space-constrained applications.

• Extended MTUs: Such as TU830, TU833, TU835, TU838, provide more terminals and functions (e.g., fuse per channel).

• Redundant MTUs: Such as TU844, TU845, support module redundancy configuration.

2. Signal Wiring Methods

• Voltage Input: Directly connect to the corresponding channel's voltage input terminal.

• Current Input: Converted to voltage signal via a built-in 250 Ω resistor.

• HART Communication: Requires shielded cables, and the external power supply must be HART compatible.

3. Power Distribution

• The module receives 24 V power from the ModuleBus and provides isolated transmitter power for each channel.

• If the transmitter requires higher starting current, it is recommended to use an external HART-compatible power supply.

V. Installation and Maintenance Recommendations

1. Installation Notes

• Ensure the module is installed in a powered-off state.

• Wire correctly according to the selected MTU type, referring to the corresponding wiring diagram.

• Use shielded cables to reduce electromagnetic interference, especially when using HART communication.

• Comply with local electrical installation codes and safety standards.

2. Diagnostics and Troubleshooting

• Quickly determine module status via front panel LED indicators:

• Green R (Run): Module operating normally.

• Yellow W (Warning): Recoverable channel or configuration warning exists.

• Red F (Fault): Module or channel has a serious error.

• View detailed diagnostic information via system software to locate specific fault points.

3. Maintenance Recommendations

• Periodically check wiring for tightness and cable integrity.

• Ensure good ventilation for the module to avoid overheating.

• In environments with dust or corrosive gases, additional protective measures are recommended.