Overview
The Allen-Bradley 1756-IF8H is a ControlLogix 8-point analog input module designed for HART-enabled data acquisition in distributed control systems. It combines differential analog input channels with on-board HART modem capability, enabling simultaneous measurement of process values and HART device diagnostics on each channel. This module integrates seamlessly into ControlLogix chassis-based architectures and is compatible with Studio 5000 Logix Designer programming software.
Key Features
- Eight (8) differential analog input channels with individual HART modem per module
- Configurable current inputs: 0–20 mA or 4–20 mA (HART standard)
- Configurable voltage inputs: ±10 VDC, 0–5 VDC, 1–5 VDC, 0–10 VDC
- HART revisions 5, 6, and 7 compatibility
- 16–21 bit resolution for precise analog-to-digital conversion
- Three data format options: analog only, analog + HART PV, analog + HART by channel
- On-board data alarming and real-time channel sampling
- 36-pin spring clamp removable terminal block (RTB) connection
Technical Specifications
- Input Channels: 8 differential
- Current Input Ranges: 0–20 mA, 4–20 mA
- Voltage Input Ranges: ±10 VDC, 0–5 VDC, 1–5 VDC, 0–10 VDC
- Resolution: 16–21 bits
- HART Protocol: Versions 5, 6, 7
- Backplane Current (5.1 VDC): 300 mA
- Backplane Current (24 VDC): 135 mA
- Total Backplane Power: 4.77 W
- Operating Temperature: 0–60 °C
- Connector: 36-position spring clamp terminal block
- Mounting: Chassis-based (ControlLogix frame)
- Certifications: CE, CUL, KC, Marine, RCM, UL
- Weight: 0.79 lb
Typical Applications
- HART transmitter integration for pressure, temperature, and flow measurement
- Multi-channel process data acquisition with diagnostic access
- Distributed control systems requiring real-time analog monitoring
- Batch and continuous process manufacturing
- Environmental and facility monitoring
- Chemical processing and water treatment systems
Compatibility & Replacements
Compatible With
- ControlLogix 1756 chassis (1756-A10, A13, A16, A19, A23, A25)
- CompactLogix 5370 with 1756 adapter (1756-DNB)
- Studio 5000 Logix Designer (v28 and later)
- HART Field Device Integration (FDI) in Studio 5000
- EtherNet/IP networks via ControlLogix gateway
- HART-enabled sensor and transmitter devices (revisions 5, 6, 7)
Replaces / Drop-In Replacement For
- Earlier 1756-IF8H firmware versions (upgradeable to v3.012)
- Note: The 1756-IF8H (non-isolated differential) differs from the 1756-IF8IH (isolated current input). Verify your input signal requirements before ordering.
Works With
- Studio 5000 Logix Designer programming environment
- ControlLogix processor instruction set (analog input instructions)
- HART communication protocol (master-mode communication per channel)
- Removable terminal block options: 1756-TBCH (spring clamp), 1756-TBS6H
- Rockwell Automation firmware updates and diagnostic tools
