Overview
The Allen-Bradley 1746-NT4 is a thermocouple/millivolt input module designed for the SLC 500 family of programmable logic controllers. This module provides SLC 500 processors with digitally converted thermocouple or millivolt (mV) analog data received and stored in its image table. The 1746-NT4 module has 4 backplane isolated input channels.
Key Features
- Interfaces to thermocouple types J, K, T, E, R, S, B, and N, and accepts direct +/-50 mV and +/-100 mV analog input signals.
- Two cold-junction compensation (CJC) sensors retain thermocouple input signal accuracy instead of offset voltages.
- Does not require any external power supply as it receives 5 Volts DC and 24 Volts DC power from the SLC 500 power supply through its backplane.
- Two CJC sensors integrated into the removable terminal blocks provide temperature correction to maintain thermocouple accuracy.
- Removable terminal strip for easy field wiring and maintenance.
- Backplane isolated inputs prevent signal interference and ground loops.
Technical Specifications
- Input Channels: 4 backplane isolated input channels
- Thermocouple Types Supported: J, K, T, E, R, S, B, and N
- mV Input Range: +/-50 mV and +/-100 mV
- Backplane Current (5V): 60 mA
- Backplane Current (24V): 40 mA
- Power Consumption (5V): 0.3 Watts
- Power Consumption (24V): 0.5 Watts
- Operating Temperature: 0°C to +60°C (+32°F to +140°F)
- Storage Temperature: -40°C to +85°C (-40°F to +185°F)
- Series: B
- Cold-Junction Compensation: Dual integrated CJC sensors
Typical Applications
Applications include temperature measurement using thermocouples in industrial processes, monitoring low-level millivolt signals in process control systems, and upgrading or expanding SLC 500 PLC systems with analog temperature inputs. Common uses include furnace temperature control, oven monitoring, process heating, and laboratory data acquisition systems.
Compatibility & Replacements
Compatible With
- Allen-Bradley SLC 500 processors (all models)
- SLC 5/01, 5/02, 5/03, 5/04, 5/05 processors
- RSLogix 500 programming software
- Modular chassis-based SLC 500 systems
- Remote I/O configurations (requires block transfers)
Replaces / Drop-In Replacement For
- Previous generation 1746-NT4 units (Series A)
- Verify compatibility with your system integrator before ordering if replacing non-standard configurations.
Works With
- RSLogix 500 configuration and programming
- Block transfer instructions for remote I/O
- Standard thermocouple extension wire and sensors
- Allen-Bradley 1492 interface modules
- Removable terminal block 1746-RT32 (spare part)
