1756-IRT81

Overview of Allen Bradley 1756-IRT8I

The Allen Bradley 1756-IRT8I ControlLogix analog input module is designed for high-performance temperature monitoring in industrial automation environments. This module features eight individually isolated channels capable of accepting RTD, thermocouple, and millivolt signals, making it suitable for complex process control applications. Each input channel is configurable for a variety of sensor types, including multiple platinum, nickel, and copper RTDs, as well as Type B, C, D, E, J, K, N, R, S, and T thermocouples. The module is part of the Allen Bradley ControlLogix platform and provides superior resolution thanks to advanced sigma-delta analog-to-digital conversion. Data is output as IEEE 32-bit floating point format, ensuring high precision and compatibility with HMI, SCADA, and DCS systems. Installation is straightforward with compatible removable terminal blocks (1756-TBCH or 1756-TBS6H) and built-in diagnostic features such as wire-off detection and cold junction compensation sensors, enabling reliable integration and system maintenance.

Key Features of Allen Bradley 1756-IRT8I

• Eight isolated input channels for RTD, thermocouple, and millivolt signals
• High resolution analog-to-digital conversion (up to 24 bits usable resolution)
• Onboard cold junction compensation for accurate thermocouple measurements
• Multiple input ranges and sensor types supported
• Configurable alarms for under/over-range and wire-off detection
• Synchronized input sampling for real-time control applications
• No field calibration required for simplified operation
• Compatible with Allen Bradley ControlLogix chassis and terminal blocks

Technical Specs of 1756-IRT8I

• Module Type: Analog RTD / Thermocouple / Millivolt Input
• Inputs: 8 individually isolated channels
• Compatible RTD Types: Platinum (100, 200, 500, 1000 Ω, alpha=385/3916), Nickel (100, 120, 200, 500 Ω, alpha=618/672), Copper (10 Ω)
• Compatible Thermocouple Types: B, C, D, E, J, K, N, R, S, T, TXK/XK (L)
• Millivolt Signal Range: -100 to +100 mV
• Current Draw: 200 mA @ 5.1 VDC, 150 mA @ 24 VDC
• Operating Temperature: 0 to 60°C (32 to 140°F)
• Accuracy: Cold junction compensation ±0.3°C
• Certifications: CE, CCC, cUL, KC

Applications / Use Case

The Allen Bradley 1756-IRT8I is widely used in industries requiring precise temperature measurement and control, such as chemical processing, pharmaceuticals, food and beverage, and energy production. The module is ideal for monitoring and regulating critical process variables where multiple sensor inputs must be managed reliably in one module. Common use cases involve connecting a variety of RTDs and thermocouples to monitor reactor temperatures, storage tanks, heat exchangers, and batch processing lines. With its high channel density and individual isolation, the 1756-IRT8I simplifies wiring and ensures signal integrity in complex installations. The data can be integrated into PLC logic for PID control, trending alarms, or transmitted to SCADA systems for centralized monitoring, making the module a dependable choice for applications where accuracy, reliability, and advanced diagnostics are required.

Related Resources

• LeadTime.ca – Industrial Automation Components & Repair Services
• View All Allen Bradley Products
• Top PLC Brands Compared: Siemens, Allen Bradley & Mitsubishi
• Allen Bradley 1756-EN2TR EtherNet/IP Module for ControlLogix Systems
• Allen Bradley 1769-OF8 Analog Output Module for Process Control