Overview
The Allen-Bradley 1771-NT1 is a specialized high-resolution thermocouple and millivolt input module designed for PLC-5 systems. This module features eight thermocouple and millivolt input channels, making it ideal for demanding temperature measurement and process control applications requiring precision and isolation. With 16-bit resolution, the module provides 1000V isolation between channels, ensuring accurate signal acquisition in noise-sensitive environments.
Key Features
- Eight high-resolution thermocouple and millivolt input channels
- Compatible with thermocouple sensors Type B, E, J, K, T, R, and S, and resistance signals of ±105 mV
- Cold junction compensation, self-calibration, selectable alarms, input detection, and self-diagnostics
- 16-bit conversion resolution with 1000V isolation between channels
- Block Transfer Read (BTR) and Block Transfer Write (BTW) instructions for efficient data transfer
- Input impedance exceeding 10 MOhms with 140 Volts AC RMS continuous overvoltage protection
Technical Specifications
- Input Channels: 8 thermocouple and millivolt inputs
- Input Range: ±105 mV for millivolt and thermocouple types
- Resolution: 16-bit conversion
- Isolation: 1000V between channels
- Backplane Current: 1 Amp @ 5 VDC
- Power Consumption: 5 Watts at 5 Volts
- Operating Temperature: 0 to 60 degrees Celsius (32 to 140 degrees Fahrenheit)
- Storage Temperature: -40 to 85 degrees Celsius (-40 to 185 degrees Fahrenheit)
- Humidity Range: 5% to 95% relative humidity without condensation
- Input Impedance: >10 MOhms
- Overvoltage Protection: 140 Volts AC RMS continuous
- Update Time: 25 milliseconds maximum
- Input Bandwidth: 9 Hertz
- Normal Mode Rejection: 50dB/60dB minimum (50/60 Hertz)
- Common Mode Rejection: 150dB typical (60 Hertz)
Typical Applications
This module is ideal for use in temperature applications with higher criticality and accuracy requirements. Common industrial applications include:
- Precision temperature measurement in furnace control systems
- Multi-point thermocouple monitoring in process equipment
- Cold junction compensation for accurate temperature sensing
- Data acquisition systems requiring high input isolation
- Equipment monitoring with extended temperature measurement ranges
Compatibility & Replacements
Compatible With
- PLC-5 systems compatible with any 1771 I/O chassis
- Thermocouple types B, E, J, K, T, R, and S sensors
- Millivolt and resistance signal inputs (±100 mV range)
- Block Transfer Read (BTR) and Block Transfer Write (BTW) instructions
- Systems excluding PLC-2 processors
Replaces / Drop-In Replacement For
The 1771-NT1 Series B is a direct replacement for legacy PLC-5 thermocouple input modules requiring high-resolution analog measurement. Verify part compatibility with your system integrator before ordering, particularly regarding firmware revision requirements.
Works With
- Allen-Bradley PLC-5 programming environments
- Block Transfer protocol for data communication
- 1771-series I/O chassis and backplane systems
- Thermocouple and millivolt signal conditioning hardware
- Industrial temperature measurement and control systems
