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

Product Description

The Allen-Bradley 1794-IR8 is an eight-channel RTD input module designed for Flex I/O systems. It provides precise resistance temperature detector (RTD) measurement with high resolution and accuracy, supporting multiple terminal base units for flexible installation.

Technical Specifications

• Manufacturer: Allen-Bradley

• Product Line: Flex I/O

• Part Number: 1794-IR8

• Product Type: RTD Input Module

• Number of Inputs: 8 channels

• Module Location: Compatible with 1794-TB2, -TB3, -TB3S, -TB3T, -TB3TS terminal base units

• Nominal Input Range: 1–433 ohms

• RTD Excitation Current: 718.36 µA

• Resolution: 16 bits across 435 ohms

• Accuracy:

• Normal mode: 0.05% full scale (max, without calibration)

• Enhanced mode: 0.01% full scale (typical, low humidity)

• Isolation Voltage: 850 V DC tested for 1 s (inputs and user power to logic side)

• Data Format: 16-bit two’s complement or offset binary (unipolar)

• Channel Bandwidth: 0–2.62 Hz (-3 dB)

• Indicators: One red/green power status LED

• Flexbus Current: 20 mA

• Power Dissipation: 3.0 W max @ 31.2 V DC

• Thermal Dissipation: 10.2 BTU/hr max @ 31.2 V DC

• Weight: 1 kg

Features

• Eight-channel RTD input capability for distributed temperature sensing

• High accuracy with selectable normal and enhanced modes

• Isolated channels for improved signal integrity

• Compact Flex I/O design for modular installation

• Diagnostic LED indicator for power status monitoring

Application Scenarios

• Process Monitoring: Accurate RTD measurement for industrial temperature control

• Distributed I/O Systems: Flexible integration with Flex I/O terminal bases

• Legacy and Expansion Projects: Compatible with existing Flex I/O installations

FAQ

• Q: How many input channels does the 1794-IR8 provide?  A: Eight RTD input channels.

• Q: What terminal bases are supported?  A: 1794-TB2, -TB3, -TB3S, -TB3T, and -TB3TS.

• Q: What is the accuracy of the module?  A: 0.05% full scale in normal mode, 0.01% typical in enhanced mode.

• Q: Does the module provide isolation?  A: Yes, tested at 850 V DC for 1 second.

• Q: How does this compare to the 1794-IR4?  A: The 1794-IR8 supports eight channels, while the 1794-IR4 provides four, making the IR8 suitable for higher-density applications.