Allen-Bradley 1746-NI4 SLC 500 4-Channel Analog Input Module

Product Overview

The Allen-Bradley 1746-NI4 provides high-resolution analog-to-digital conversion for SLC 500 modular hardware systems. This module features 4 differential input channels, designed to receive and process voltage or current signals from field devices such as pressure transducers, flow meters, and temperature transmitters. It translates these analog signals into digital values for the SLC 500 processor. Although the manufacturer officially discontinued this series in 2021, we supply this unit as 100% Brand New original factory stock, ensuring your legacy control systems remain operational without the risks of refurbished hardware.

Technical Specifications

The 1746-NI4 interfaces directly with the SLC backplane and supports standard industrial signal ranges:

Engineering Advantages

• Differential Input Precision: The module utilizes differential inputs to reject common-mode noise. This architecture cancels out electrical interference that typically affects long cable runs in high-EMI factory environments, ensuring stable data readings.

• Selectable Signal Ranges: DIP switches located on the circuit board allow engineers to configure each channel for either voltage or current independently. This flexibility simplifies spare parts inventory by allowing one 1746-NI4 to serve multiple application types.

• Low Backplane Load: The module consumes minimal current (25 mA @ 5V DC), preserving the power budget of the SLC 500 chassis for high-density digital I/O or communication modules.

• Direct Hardware Integration: The unit slides into any available slot in a 1746 chassis (except slot 0). It uses a removable terminal block, which enables rapid module replacement without disconnecting individual field wires, significantly reducing downtime during maintenance.

FAQs

• Q: How do I switch between voltage (10V) and current (20mA) modes?

• A: You must set the internal DIP switches on the module's circuit board before installation. The module recognizes the signal type based on these physical switch positions and your software configuration in the I/O rack image.

• Q: Does this module require an external power supply for the analog loop?

• A: The 1746-NI4 draws its operating power from the SLC backplane. However, your field transmitters (2-wire or 4-wire) typically require their own external 24V DC loop power to drive the 4-20mA signal to the module.

• Q: Can I replace a failed 1746-NI4 with this "Brand New" unit without changing code?

• A: Yes. As a 100% Brand New original component, it functions as a direct drop-in replacement. Simply move the existing terminal block to the new module and insert it into the same chassis slot to restore system operation.

• Q: Why should I buy "Brand New" instead of a cheaper refurbished unit for this discontinued part?

• A: Analog modules contain sensitive capacitors and A/D converters that drift or fail with age. Buying a Brand New unit guarantees factory-spec accuracy and avoids the calibration errors and intermittent signal "noise" common in used or "pull" components.