ABB Bailey NTAI04 Analog Input Termination Unit

ABB Bailey NTAI04 RTD Analog Input Termination Unit

The ABB Bailey NTAI04 is an RTD Analog Input Termination Unit for the INFI 90 distributed control system. It provides dedicated termination and signal conditioning for Resistance Temperature Detector (RTD) sensors, delivering high-accuracy temperature measurement for critical process control applications.

Key Specifications

• Part Number: NTAI04
• Assembly Number: 6635700A1
• Product Type: RTD Analog Input Termination Unit
• Series: INFI 90 / Symphony
• Manufacturer: ABB / Bailey Controls
• Channels: 8 channels (typical)
• Input Type: RTD (3-wire or 4-wire configuration)
• Resolution: 0.1°C
• Terminals: 32 screw terminals
• Power Requirements: 24 V DC or 48 V DC (varies by source)
• Dimensions: 178 × 25 × 178 mm (7.0" × 1.0" × 7.0") or 220 × 160 × 35 mm
• Weight: 0.3 kg to 0.8 kg (varies by source)
• Operating Temperature: 0°C to 60°C (32°F to 140°F)
• Storage Temperature: -40°C to 85°C
• Humidity: 5% to 95% non-condensing
• Mounting: INFI 90 field termination panel
• Supported Protocols: Modbus, PROFIBUS DP, Foundation Fieldbus (communication gateway variants)

Features & Benefits

1. RTD-Optimized Design: Dedicated circuitry for 3-wire and 4-wire RTD connections eliminates lead wire resistance errors.
2. High Resolution: 0.1°C resolution provides precise temperature measurement for critical control loops.
3. 32 Screw Terminals: Ample termination points for multi-wire RTD configurations and shield grounding.
4. Signal Isolation: Galvanic isolation protects DCS electronics from field ground loops.
5. Fieldbus Gateway Option: Some variants support Modbus, PROFIBUS, and Foundation Fieldbus for flexible integration.

Applications

• Boiler and turbine bearing temperature monitoring
• Reactor vessel temperature measurement
• Heat exchanger performance monitoring
• Process heater and furnace temperature control
• Environmental chamber temperature profiling

FAQ

Q: What RTD types does NTAI04 support?
A: The NTAI04 typically supports Pt100, Pt200, Pt500, Pt1000, Ni100, Ni120, and Cu10 RTD types. Verify specific type support in your module documentation.

Q: Can NTAI04 be used with thermocouples?
A: The NTAI04 is optimized for RTD sensors. For thermocouple applications, use the NTAI02 or dedicated thermocouple termination units with appropriate slave modules.

Q: What is the difference between 3-wire and 4-wire RTD connections on NTAI04?
A: 3-wire compensates for lead wire resistance in one leg; 4-wire uses Kelvin connection to eliminate lead resistance entirely, providing highest accuracy.

Installation Guide

1. Mount NTAI04 in standard INFI 90 field termination panel slot.
2. Connect RTD sensors to designated terminals per wiring diagram (3-wire or 4-wire).
3. Verify lead wire resistance compensation settings for 3-wire configurations.
4. Connect shield wires to ground bus at one end only.
5. Link NTAI04 to IMASI02/IMASI03 analog input slave module.
6. Configure RTD type, temperature range, and engineering units in MFP function blocks.
7. Calibrate against ice bath (0°C) and boiling point (100°C) references.

Selection Tips

• RTD Type: Confirm your temperature sensor type (Pt100, Ni100, etc.) is supported by NTAI04.
• Wiring Configuration: Use 4-wire connection for highest accuracy; 3-wire is acceptable for most industrial applications.
• Temperature Range: Verify RTD element covers your process temperature range (Pt100: -200°C to +850°C typical).
• Communication: If fieldbus gateway functionality is required, specify Modbus/PROFIBUS variant.