Allen-Bradley 1756-IF8 ControlLogix 8-Point Analog Voltage/Current Input Module

Product Performance Overview

The 1756-IF8 is a versatile analog input module engineered for the Allen-Bradley ControlLogix platform, providing high-accuracy signal acquisition for industrial automation systems. This module supports up to eight channels and is capable of interfacing with a variety of voltage and current-based field sensors. By utilizing advanced Sigma-Delta analog-to-digital conversion, the 1756-IF8 ensures precise data representation for critical process variables. Its flexible configuration allows for multiple wiring modes, including single-ended, differential, and high-speed differential inputs, making it a standard choice for complex manufacturing and process control applications.

Technical Characteristics

• Manufacturer: Allen-Bradley / Rockwell Automation

• Product Line: ControlLogix 1756

• Model Number: 1756-IF8

• Input Channels: 8 Single-ended, 4 Differential, or 2 High-speed Differential

• Signal Ranges: ±10V, 0–10V, 0–5V, and 0–20 mA

• Conversion Technology: Sigma-Delta

• Resolution: 16-bit (Voltage and Current)

• Backplane Current Draw: 150 mA @ 5.1V DC; 40 mA @ 24V DC

• Power Dissipation: 1.73W (Voltage) to 2.33W (Current)

• Data Formatting: IEEE 32-bit floating point or 16-bit Integer (2's complement)

• Input Impedance: Voltage > 10 Megohms; Current 249 Ohms

• Removable Terminal Blocks: Compatible with 1756-TBCH or 1756-TBS6H

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

• Weight: 0.26 kg (0.56 lbs)

Professional Application and Installation

The 1756-IF8 is optimized for high-density control cabinets where precise monitoring of flow, pressure, or level is required. Its ability to handle differential inputs provides superior noise rejection in electrically noisy environments. The module features on-board diagnostics to detect open-wire conditions or out-of-range signals, enhancing system reliability. To maintain the modularity of the ControlLogix system, the 1756-IF8 uses a Removable Terminal Block (RTB), allowing for hardware swaps without the need to disconnect permanent field wiring.

Frequently Asked Questions

Can the 1756-IF8 measure 4-20 mA signals?Yes, while the hardware range is 0–20 mA, the module is easily scaled within the Studio 5000 software to accurately represent 4–20 mA signals and provide under-range detection.

Does this module require an external power supply?No, the 1756-IF8 draws its operating power directly from the ControlLogix backplane. However, the field-side loop power for current sensors typically requires an external 24V DC source.