Allen-Bradley 1791-NDC Analog Block I/O Module 4 Inputs 2 Outputs

Product Overview

The Allen-Bradley 1791-NDC Analog Block I/O Module is a compact, reliable component for industrial automation systems. This module provides 4 analog inputs and 2 current outputs, operating on a 24V DC power supply with a 600 mA current draw. Designed for use with Allen-Bradley PLC-2, PLC-3, PLC-5/250, PLC-5, and SLC 5/02 controllers, it communicates via block transfer or discrete transfer. The module includes a 24V DC current-limited voltage source for loop-powered current transducer inputs, making it a versatile choice for analog signal processing.

Technical Specifications Breakdown

Key parameters for the 1791-NDC are listed below for quick reference:

Industry Applications

This module is well-suited for process control environments requiring precise analog signal acquisition and current output. Common applications include monitoring temperature, pressure, or flow sensors in manufacturing lines, and controlling actuators or valves via 0-20 mA outputs. Its compatibility with legacy PLC platforms makes it a cost-effective choice for system upgrades or expansions without replacing the entire control infrastructure.

Installation & Setup Guidance

Mount the module securely in a suitable enclosure, ensuring adequate airflow for thermal dissipation (39.28 BTU/hr. max). Connect the 24V DC power supply within the 19.2 to 30V DC range, observing polarity. For analog inputs, use shielded twisted-pair cables to minimize noise. Configure input types (e.g., ±10V, 0-20 mA) via the module's selectable settings. The input impedance is 10 megaohms for voltage and 250 Ohms for current. Verify communication with the controller using block transfer or discrete transfer methods.

Maintenance & Reliability

Periodically inspect the module for dust accumulation or loose connections. Ensure ambient temperature stays within the module's operating range (refer to manufacturer documentation). The module includes indefinite short circuit protection on outputs, reducing the risk of damage from wiring faults. No user-serviceable parts inside; contact qualified personnel for any repairs.

Compatibility & Integration

It supports both block transfer and discrete transfer communication. The module provides 4 selectable analog inputs and 2 current outputs with 13-bit resolution. For loop-powered transducers, the built-in 24V DC current-limited source simplifies wiring.

Selection Guide & Purchasing Advice

When selecting the 1791-NDC, verify that your controller supports block transfer or discrete transfer communication. AutoDCSTech offers this module with detailed specifications and support. Please verify current lifecycle status and availability with AutoDCSTech before ordering.