The Allen-Bradley 1746-NR4 SLC 500 RTD/resistance input module has Four (4) channels available that are backplane-isolated. The module’s A/D conversion method is sigma-delta modulation. This module is compatible for installation to a fixed style or modular hardware SLC 500. The 1746-NR4 also comes with input filtering, particularly a low-pass digital filter that has programmable frequencies. LED status indicators are present on the 1746-NR4 module, specifically 5 indicators made up of 1 indicator for the status of the module itself and 4 indicators for the module’s channels, with 1 indicator for every channel. RTD types compatible for this module are Nickel Iron, Nickel, Copper, and Platinum. Note that this module does not require an external power supply and it does a self-calibration automatically when the filter frequency, input type, or excitation current, or when a channel is enabled. The backplane current consumptions of the 1746-NR4 module are 50 mA each at both 5 Volts DC and 24 Volts DC, and its maximum backplane power consumption is 1.5 Watts, with 0.3 Watts at 5 Volts DC and 1.2 Watts at 24 Volts DC. The maximum permanent overloads this module can handle are +/- 5 Volts DC for Volts and +/- 5 mA for the current and its maximum common-mode voltage is +/- 1 Volt. The optical isolation of the 1746-NR4 is 500 Volts DC for 1 minute between both the inputs and the chassis ground and between the inputs and the backplane. The 1746-NR4 also works at an operating temperature of 0 to 60 degrees Celsius and it can be stored at a non-operating temperature of -40 to 85 degrees Celsius.

The 1746-NR4 is an Allen-Bradley module that belongs to the SLC 500 product family. This module is a Resistance Temperature Detector (RTD) module that is used to interface RTD sensor to SLC 500 control system.

It features Four (4) RTD inputs with each channel supporting a wide variety of RTD types. Compatible RTD types include Platinum (385) 100, 200, 500 and 1000; Platinum (3816) 100, 200, 500 and 1000; Copper (426) 10, Nickel (618) 120, Nickel (672) 120, and Nickel Iron (518) 604. This RTD module can measure temperature as low as - 200 to 850 Deg. Celsius. Each input channel is built with broken sensor detection that may indicate a shorted or open circuit. When this error is detected, the module’s indication is out of range.

This module is also compatible for measuring process variables through direct wiring of resistance signals such as 0 - 150 Ohms, 0 to 500 Ohms, 0 to 1000 Ohms and 0 to 300 Ohms. This may be used not only for measuring temperature but for measuring displacement or movement or a particular device such as pick and place mechanisms, clamping equipment and many other applications.

It is compatible for installation in a fixed style hardware that uses 1746-A2 as expansion chassis or to a local chassis or remote I/O chassis of a modular style hardware. This module is not designed for installation to slot 0 of a modular style hardware as Slot 0 is dedicated for an SLC 500 Controller or Adapter module.