ABB TU846

ABB TU846 Module Termination Unit (MTU)

1. Product Description

• Redundancy Support: Features dual PROFIBUS DP ports and a failover mechanism, ensuring continuous communication in mission-critical applications by automatically switching to a backup path in case of primary port failure. This reduces downtime risks in systems where uninterrupted data flow is essential, such as safety instrumented systems (SIS).
• Signal Termination: Provides 27 isolated terminals (3×9 configuration) for connecting analog (4–20mA, 0–10V) and digital (NAMUR sensors, voltage-free contacts) signals, with color-coded wiring for easy installation and maintenance. This simplifies wiring and minimizes errors during setup.
• Rugged Design: Engineered to withstand operating temperatures from 0°C to +55°C and storage temperatures from -40°C to +70°C, resisting vibrations, moisture, and electromagnetic interference (EMI). This ensures reliable performance in extreme industrial environments, such as offshore platforms or high-temperature manufacturing facilities.
• Wide Compatibility: Works seamlessly with ABB’s S800 I/O modules (e.g., AI890 for analog input, DI890 for digital input) and third-party devices, supporting both standard and safety-related signals in a single unit. This versatility reduces the need for multiple specialized modules.

2. Technical Parameters

Parameter	Specification
Brand	ABB
Model	TU846
Type	Module Termination Unit (MTU)
Signal Terminals	27 isolated terminals (3×9 configuration)
Wiring Capacity	Supports solid/stranded wires (0.2–4 mm²)
Voltage Supply	24V DC ±10% (derived from S800 I/O system)
Communication Interfaces	PROFIBUS DP (dual ports), RJ45 (Ethernet)
Operating Temperature	0°C to +55°C (non-condensing humidity: 5%–95%)
Storage Temperature	-40°C to +70°C
Dimensions (H×W×D)	186mm × 124mm × 47mm
Weight	0.55 kg
Compatibility	ABB CI840/CI840A field communication interfaces, S800 I/O modules, and third-party devices
Certifications	CE, RoHS, ATEX/IECEx (for hazardous areas), marine compliance (ABS, BV, DNV-GL)

ABB TU846

3. Advantages and Features

• High Availability through Redundancy:
  • The dual PROFIBUS DP ports enable automatic failover, reducing downtime by up to 40% in critical applications. This is particularly valuable in industries like oil and gas, where communication failures can lead to costly shutdowns or safety incidents.
• Flexible Signal Handling:
  • Supports a mix of analog and digital signals, allowing simultaneous connection of devices such as pressure transmitters (4–20mA) and safety switches (digital signals). This versatility eliminates the need for separate termination units, streamlining system design and reducing component costs by up to 30%.
• Robust Environmental Resilience:
  • With an MTBF (mean time between failures) exceeding 150,000 hours, the TU846 offers long-term reliability even in harsh conditions. Its resistance to EMI and vibrations ensures stable signal transmission, minimizing errors in data acquisition and control.
• Space-Efficient Design:
  • At 186mm × 124mm × 47mm, the module is compact enough for retrofitting into existing control cabinets, optimizing space usage without compromising on functionality. This is ideal for applications with limited installation space, such as retrofitted industrial plants.

4. Application Areas and Case Study

Application Areas:

• Chemical Processing: Used to terminate signals from temperature, pressure, and flow sensors in chemical reactors, ensuring precise process control and compliance with safety standards.
• Oil and Gas: Integrates with valves, pumps, and gas detectors in offshore platforms and refineries, supporting redundant communication to prevent data loss in harsh marine environments.
• Power Generation: Connects turbine sensors and generator control systems in thermal and renewable energy plants, maintaining stable signal transmission for grid synchronization.
• Manufacturing: Facilitates communication between robotic arms, conveyor belts, and PLCs in automated production lines, enhancing process efficiency and reducing downtime.

Case Study:

5. Competitive Comparison

• Dual Redundancy Ports: Uniquely offers dual PROFIBUS DP connectivity, a feature that enhances system reliability in high-availability setups, which many alternatives lack.
• Mixed Signal Support: Natively handles both analog and digital signals in a single unit, reducing the need for multiple modules and simplifying inventory management.
• Stringent Certifications: Meets ATEX/IECEx and marine compliance standards, making it suitable for hazardous and offshore applications where few competitors offer equivalent safety and environmental resilience.
  

  ABB TU846

6. Selection Recommendations

• Redundancy Requirements: Choose the TU846 if your application requires failover capabilities for critical communication, such as in SIS or uninterruptible power supply (UPS) systems.
• Signal Types: Ensure the module’s terminal configuration and signal compatibility match your field devices, such as 4–20mA for analog sensors or NAMUR for digital safety switches.
• Environmental Conditions: Verify the operating temperature range (0°C to +55°C) and humidity tolerance (5%–95% non-condensing) align with your installation site, especially for outdoor or high-temperature environments.
• System Compatibility: Confirm integration with your existing ABB S800 I/O system or third-party platforms that support PROFIBUS DP or Ethernet communication protocols.

7. Precautions

• Installation:
  • Power down the entire system before installing or replacing the TU846 to prevent electrostatic discharge (ESD) damage to internal components.
  • Use shielded cables for signal connections and route them separately from high-voltage power cables to minimize EMI interference.
• Maintenance:
  • Regularly inspect terminal connections for tightness and corrosion, particularly in humid or corrosive environments.
  • Update firmware using ABB’s official software (e.g., Control Builder M) to ensure compatibility with the latest system updates and security patches.
• Storage:
  • Store unused TU846 modules in their original packaging in a dry, dust-free environment within the specified storage temperature range (-40°C to +70°C).
  • Handle the module with anti-static wrist straps or gloves to protect against ESD during handling.