Allen-Bradley HART Analog Input 1756-IF8H Module

Overview

The Allen-Bradley 1756-IF8H is an 8-channel HART-enabled analog input module for ControlLogix systems, offering precise measurement of voltage and current signals while supporting HART communication standards 5, 6, and 7. The module is designed for reliable signal acquisition with robust overvoltage protection, isolation, and high-resolution performance.

Technical Specifications

Module Details

• Model: 1756-IF8H

• Input Channels: 8 differential inputs with 1 HART modem per module

• Input Voltage Ranges: 0…5V, 1…5V, 0…10V, ±10V

• Input Current Ranges: 0…20 mA, 4…20 mA

• Resolution: 16–21 bits across all ranges

• Compatible HART Versions: HART 5, 6, 7

Performance

• Analog Scan Time: 18–488 ms (filter dependent)

• HART Scan Time: Typically 1 s per enabled channel; ~10 s for all 8 channels active

• Open Circuit Detection: 5 s

• Overvoltage Protection: 30V DC for voltage; 8V DC for current

• Isolation Voltage: 50V continuous; basic insulation type; tested 1500V AC for 60 s, I/O to backplane

Accuracy & Calibration

• Voltage Accuracy: Better than 0.05% of range (HART disabled)

• Current Accuracy: Better than 0.15% of range (HART disabled)

• Calibration Interval: 12 months typical

• Temperature Rating: North America T4A / IEC T4

Environmental & Physical

• Operating Temperature: 0°C to 60°C

• Storage Temperature: -40°C to 85°C

• Relative Humidity: 5–95% non-condensing

• Enclosure: Open-style, no protective housing

Applications

The 1756-IF8H module is ideal for precise analog signal monitoring in process control, supporting HART communication for integration with smart field devices. Typical applications include level measurement, temperature control, and flow monitoring.

FAQ

Q: How many HART channels does the module support?
A: The module provides 1 HART modem for 8 differential analog inputs.

Q: What input types are supported?
A: Voltage (0…5V, 1…5V, 0…10V, ±10V) and current (0…20 mA, 4…20 mA).

Q: What is the update time for HART readings?
A: Typically 1 s per active HART channel; around 10 s if all 8 channels are enabled.

Q: Does it offer overvoltage protection?
A: Yes, 30V DC for voltage inputs and 8V DC for current inputs.