A-B 1746-NT8 SLC 500 Thermocouple/Voltage Analog Input Module

The Allen-Bradley 1746-NT8 is an SLC 500 thermocouple/mV analog input module.

The module has eight (8) channels and is compatible with thermocouple sensors such as J, K, T, E, S, R, B, and N. It is also compatible with mV inputs such as +/- 50 mV and +/- 100 mV.

It is also compatible with mV inputs such as +/- 50 mV and +/- 100 mV. The module is compatible with both stationary and modular SLC 500s.

About the 1746-NT8

The 1746-NT8 is Allen-Bradley's SLC 500 thermocouple/voltage analog input module.

It is a chassis-mounted, eight (8) channel module that receives thermocouple/voltage signals and converts them to digital signals for retrieval by any SLC 500 processor.

It has a backplane current rating of 120mA at 5V DC and 70mA at 24V DC for a total backplane power of 2.28W.

The 1746-NT8 uses a delta-sigma signal conversion method and has a digital low-pass filter with selectable programmable filter frequencies.

The normal mode rejection between terminals is greater than 100 dB at 50-60 Hz, and the common mode rejection between input and ground is greater than 100 dB at 50-60 Hz.

The 1746-NT8 module automatically calibrates itself approximately every 2 minutes after power-up.

It provides +/-30V DC and 600W pulses for 1ms input overvoltage protection and 12.5V DC circuit isolation between inputs and chassis ground, and between inputs and backplane, with a test voltage of 500V DC for 1 minute.

The 1746-NT8 has nine green LEDs to indicate channel status and module status.

It uses the 1746-RT34 (RTB) removable terminal block to connect the input devices. The terminal block includes two (2) cold junction compensation (CJC) sensors with an accuracy of +/-1.72 degrees Celsius.

The 1746-NT8 has several selectable input types with a total input impedance greater than 10 M ohms.

Any input device connected to it must have an impedance of less than 100 ohms to meet accuracy requirements.

The 1746-NT8 offers optional open-circuit detection at 1 cycle per channel for an overall input dry-circuit response time of 400 milliseconds.

The functional temperature range of the module is 0 degrees Celsius to 60 degrees Celsius. The functional temperature range of the module is 0 degrees Celsius to 60 degrees Celsius.

The modules are UL and CUL recognized.

1746-NT8 is an analog input module belonging to the SLC 500 product family.

The module is specifically designed for thermocouple/millivolt inputs and is compatible with SLC 500 processors such as SLC 5/01. 5/02. 5/03. 5/04. and 5/05. It can be used with SLC fixed or modular hardware categories.

Similar to other analog input modules, the 1746-NT8 uses Sigma-Delta modulation to convert received analog signals to digital values.

The converted data is stored in the module's local memory and transferred to the CPU to create a data table to store the digitally converted values.

The module can be mounted in a fixed chassis, specifically using the 1746-A2 chassis.

If used with a modular controller, the module can be installed in any slot except slot 0.

Slot 0 is always reserved for controllers or communication adapters such as Remote IO, Data Highway Plus (DH+), and Ethernet communication modules.

Available data formats for input signals include engineering units, proportional-integral-derivative (PID) scaling, and proportional counting.

For thermocouple and millivolt input signals, PID proportional is the most compatible data format.

The module is capable of detecting open circuits, under-range, over-range, and channel errors.

These error alarms are assigned specific bits that can be accessed by monitoring systems such as Human Machine Interfaces (HMI) and Supervisory Control and Data Acquisition (SCADA) systems.