Product Overview

The Allen-Bradley 1746-NR4 provides high-precision temperature and resistance monitoring for the SLC 500 PLC platform. This 4-channel module interfaces directly with various Resistance Temperature Detectors (RTDs) and direct resistive sources, converting these physical signals into digital data for the processor. It eliminates the need for external signal transmitters, reducing both hardware costs and potential points of failure. We supply this unit as 100% Brand New and Original in factory packing, ensuring the highest accuracy for your critical process thermal loops.

Technical Specifications

Engineering Advantages

• Broad Sensor Compatibility: The 1746-NR4 supports a massive library of RTD types, including Platinum (100, 200, 500, 1000 Ω), Nickel, and Copper. This versatility allows you to standardize on one module type across your entire facility, regardless of the varied sensor types installed on your machinery.

• Superior Noise Rejection: Utilizing Sigma-Delta modulation and a programmable low-pass digital filter, the module effectively ignores electromagnetic interference (EMI) commonly found near large motor drives. The programmable notch frequencies allow you to filter out specific 50Hz or 60Hz line noise.

• Granular Temperature Precision: With a resolution of 0.01 °C, this module handles demanding applications like chemical reaction monitoring or food processing where tight thermal tolerances are non-negotiable.

• Flexible Chassis Placement: You can install the 1746-NR4 in any available I/O slot of an SLC 500 chassis except for Slot 0 (reserved for the CPU). This provides maximum freedom during system design or field retrofits.

FAQs

Does the 1746-NR4 require calibration?

The 1746-NR4 performs self-calibration upon power-up and periodically during operation. This feature compensates for component aging and temperature drift, ensuring that your measurements remain accurate without manual intervention or specialized field calibration equipment.

Can I mix different types of RTDs on the same module?

Yes. You can configure each of the four channels independently through your software (RSLogix 500). For example, Channel 0 can monitor a 100-ohm Platinum RTD while Channel 1 measures a 1000-ohm Nickel-Iron sensor.

What wiring configuration does the module support?

The module supports 2-wire, 3-wire, and 4-wire RTD configurations. For the highest accuracy and to compensate for lead-wire resistance, we strongly recommend using a 3-wire or 4-wire setup, especially if the sensors are located far from the PLC cabinet.

How do the LED indicators help with troubleshooting?

The module features five green status indicators. One LED monitors the overall module health, while the remaining four correspond to individual channels. If a channel LED turns off or flashes, it typically indicates an open circuit, short circuit, or out-of-range sensor condition, allowing for rapid field diagnostics.