1794-IR8 | Allen-Bradley | FLEX I/O RTD Input Module

Product Overview

The Allen-Bradley 1794-IR8 serves as a high-density temperature acquisition module within the FLEX I/O platform. This module interfaces with up to eight Resistance Temperature Detectors (RTDs) or direct resistance sensors, converting low-level signals into precise digital data for the controller. We supply this unit as 100% Brand New and Original, ensuring your distributed I/O system maintains lab-grade thermal monitoring accuracy in rugged industrial environments.

Technical Specifications

Engineering Advantages

• High-Density Thermal Mapping: The 1794-IR8 packs eight channels into a compact FLEX I/O footprint. This high density allows for comprehensive temperature monitoring across large equipment or reactor vessels without significantly expanding the control cabinet size.

• Precision Signal Conversion: The 16-bit resolution delivers exceptional sensitivity for critical thermal processes. In Enhanced Mode, the module achieves a typical accuracy of 0.01% of full scale, enabling the control system to detect minute temperature shifts and adjust PID loops with surgical precision.

• Robust Electrical Isolation: Tested at 850V DC, the module provides a secure barrier between field-side inputs and the logic circuitry. This isolation protects the Flexbus and the primary controller from ground loops and high-voltage transients that often occur in heavy industrial power environments.

• Versatile Terminal Integration: The module docks directly onto various FLEX I/O terminal bases, including the 1794-TB2, -TB3, and -TB3T. This modularity allows technicians to replace the electronic component without disturbing the field wiring, dramatically reducing downtime during maintenance cycles.

• Advanced Noise Filtering: A low channel bandwidth (0-2.62Hz) effectively filters out high-frequency electromagnetic interference (EMI) commonly generated by motors and variable frequency drives (VFDs). This ensures stable, jitter-free temperature readings for the DCS or PLC.

FAQs

• Which RTD types does the 1794-IR8 support?

  The module supports a wide range of industry-standard RTDs, including 100$\Omega$ Platinum (385 and 392 curves), 200$\Omega$ Platinum, 10$\Omega$ Copper, and 120$\Omega$ Nickel. You can configure each channel independently via the software to match your specific sensor type.

• Does this module require a separate power supply?

  Yes, the 1794-IR8 requires 24V DC user power to operate the analog circuitry. Ensure your power supply maintains stability, as the module consumes up to 3.0W at 31.2V DC.

• Can I use 2-wire, 3-wire, or 4-wire RTDs?

  The 1794-IR8 supports 2-wire and 3-wire RTD configurations. For high-precision applications, we recommend 3-wire wiring to compensate for lead-wire resistance, ensuring the module measures the sensor's actual resistance rather than the cable's.

• How does the "Enhanced Mode" affect performance?

  Enhanced Mode increases the accuracy and repeatability of the conversion at the cost of a slightly longer update time. Use this mode for slow-moving thermal processes where precision is more critical than instantaneous response speed.