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 dcs-sis.com 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.