ABB TB852 (Order Code: 3BSC950263R1) RCU Link Terminator  

1. Key Parameters

• Product Model: TB852
• Order Code/Part Number: 3BSC950263R1 (unique identifier for procurement and system compatibility verification)
• Core Function: Terminates RCU communication links; suppresses signal reflections, filters EMI, and stabilizes data transmission in distributed control networks
• Communication Compatibility:
  • Target Bus/Link Type: ABB proprietary RCU communication link (supports serial-based or low-speed bus protocols for RCU-I/O/controller data exchange)
  • Supported RCU Series: Compatible with ABB RCU modules for AC 800M DCS and related distributed control systems
• Electrical Specifications:
  • Termination Resistance: 120Ω (fixed, matched to RCU link characteristic impedance to eliminate signal reflections)
  • Signal Voltage Range: 0V~5V DC (compatible with RCU link logic levels)
  • Insulation Voltage: 2.5kVrms (between termination circuit and ground; prevents ground loops)
  • EMI Filtering: Integrated RC low-pass filter (cutoff frequency: 1MHz) to reduce high-frequency noise
• Mechanical Specifications:
  • Dimensions (W×H×D): 22.5mm × 85mm × 65mm (1-module width, compatible with 35mm DIN rail mounting)
  • Enclosure Material: Flame-retardant plastic (UL94 V-0 rating; resistant to industrial chemicals and impact)
  • Mounting: 35mm standard DIN rail (EN 60715) or panel mounting (via threaded inserts)
  • Terminal Type: Screw terminals (accepts 0.5mm²~1.5mm² copper conductors; torque range: 0.5~0.8N·m)
• Environmental Ratings:
  • Operating Temperature Range: -25℃~+70℃ (-13℉~158℉)
  • Storage Temperature Range: -40℃~+85℃ (-40℉~185℉)
  • Humidity Tolerance: ≤95% RH (non-condensing, 40℃)
  • Vibration Resistance: 10~500Hz, 2g acceleration (IEC 60068-2-6)
  • Shock Resistance: 30g acceleration (11ms duration, IEC 60068-2-27)
• Compliance Standards: IEC 61000-6-2 (EMC immunity for industrial environments), EN 60947-1 (low-voltage switchgear safety), UL 508 (industrial control equipment)

2. Key Features

• Impedance-Matched Termination: Fixed 120Ω resistance matches the characteristic impedance of ABB RCU communication links—eliminating signal reflections that cause data corruption (e.g., bit errors, frame drops) in long-distance (≥100m) or high-speed network segments.
• Integrated EMI Filtering: Built-in RC low-pass filter suppresses high-frequency electromagnetic noise (from motors, inverters, or power cables) that interferes with RCU link signals—ensuring stable communication in noisy industrial environments (e.g., manufacturing plants, mining sites).
• Compact DIN Rail Design: 22.5mm slim profile fits in dense DIN rail setups (e.g., control cabinets with RCU modules, I/O racks)—saving space while maintaining easy access for wiring and maintenance.
• Wide Compatibility: Optimized for ABB RCU modules and AC 800M DCS networks—requires no custom configuration (plug-and-play operation) and integrates seamlessly with existing RCU communication infrastructure.
• Robust Insulation: 2.5kVrms insulation between the termination circuit and ground prevents ground loops (a common cause of communication failure in distributed systems) and protects the unit from voltage transients.
• Flame-Retardant Enclosure: UL94 V-0 rated plastic enclosure resists ignition and limits flame spread—enhancing safety in industrial environments where flammable materials or high temperatures are present (e.g., oil refineries, chemical plants).
• Easy Wiring & Maintenance: Clearly labeled terminals (e.g., “RCU Link In,” “RCU Link Out,” “Ground”) and tool-less DIN rail mounting simplify installation. Screw terminals ensure secure wire connections that resist loosening from vibration.

3. Application Fields

• AC 800M DCS Networks: Terminates RCU communication links in ABB AC 800M distributed control systems—used in power plants, refineries, and chemical facilities to maintain reliable data exchange between central controllers and remote I/O/RCU modules.
• Remote Control Unit (RCU) Deployments: Stabilizes links between RCUs and field devices (e.g., sensors, actuators) in distributed automation setups (e.g., pipeline monitoring stations, offshore platforms) where communication distances exceed 50m.
• Industrial Manufacturing Lines: Terminates RCU-based communication for machine-level control (e.g., automotive assembly lines, electronics production lines)—ensuring uninterrupted data flow between line controllers and remote process sensors.
• Water & Wastewater Treatment Plants: Used in distributed control networks for pump stations, filtration units, and chemical dosing systems—where RCU links connect remote equipment to central SCADA systems.
• Renewable Energy Facilities: Terminates RCU communication between wind turbine/solar inverter controllers and central monitoring systems—maintaining data integrity in outdoor, high-noise environments (e.g., wind farms with high EMI from power converters).
• Mining & Metals Operations: Stabilizes RCU links in underground mines or smelting facilities—withstanding dust, vibration, and temperature extremes while ensuring reliable communication for crusher control, conveyor monitoring, and safety systems.

4. Precautions

• System Compatibility: Use exclusively with ABB RCU communication links and AC 800M-compatible RCU modules—non-ABB links or third-party terminators may mismatch impedance, causing signal degradation or network failure.
• Termination Placement: Install at the end of RCU link segments (not in mid-segment). Mid-segment termination disrupts signal flow, while missing end-terminaion leads to reflections and data errors.
• Impedance Matching: Do not modify the fixed 120Ω termination resistance—altering resistance will break impedance matching and render the unit ineffective. Replace the unit if the termination resistor is damaged (verified via multimeter).
• Grounding Requirement: Connect the unit’s ground terminal to a clean, low-resistance industrial ground (≤1Ω). Poor grounding reduces EMI filtering effectiveness and increases the risk of ground loops.
• Environmental Protection: Install in a sealed control cabinet in harsh environments (e.g., dusty mines, coastal areas with salt spray). Avoid direct exposure to water, corrosive gases, or temperatures beyond -25℃~+70℃.
• Wiring Safety: Ensure RCU link cables are rated for industrial use (e.g., shielded twisted-pair, 0.5mm²~1.5mm² copper). Do not run link cables alongside high-voltage power cables (≥30cm spacing) to minimize EMI.
• Maintenance Checks: Periodically inspect terminals for corrosion or loose connections (common in humid environments). Verify termination resistance (120Ω ±5%) with a multimeter—replace the unit if resistance deviates beyond specification