Allen-Bradley 1794-IRT8 FLEX I/O RTD Input Module

Overview

The Allen-Bradley 1794-IRT8 is a FLEX I/O temperature input module engineered for industrial process monitoring and machine control applications requiring accurate RTD and thermocouple measurements. The module provides eight configurable non-isolated input channels divided into two independent groups of four channels.

Designed for distributed I/O architectures, the module interfaces directly with a FLEX I/O system and supports a wide range of RTD, thermocouple, and millivolt input signals. Its compact DIN rail design allows installation in control panels with limited space while maintaining dependable temperature acquisition performance.

The 1794-IRT8 operates from a 24V DC supply and includes onboard diagnostics with dedicated status indicators for power and open-wire fault detection.

Key Features

• Eight configurable temperature input channels

• Compatible with both RTD and thermocouple sensors

• Supports millivolt signal acquisition

• 14-bit analog resolution

• DIN rail mounted FLEX I/O module

• Fast conversion and throughput performance

• Integrated open-input diagnostics

• Suitable for industrial temperature monitoring systems

• Compatible with multiple FLEX terminal bases

• Designed for distributed PLC and DCS architectures

Technical Specifications

Supported RTD Inputs

The 1794-IRT8 supports a broad range of resistance temperature detectors including:

• 100 Ω Platinum RTD α = 0.00385

• 100 Ω Platinum RTD α = 0.003916

• 200 Ω Platinum RTD

• 500 Ω Platinum RTD

• 100 Ω Nickel RTD

• 120 Ω Nickel RTD

• 200 Ω Nickel RTD

• 500 Ω Nickel RTD

• 10 Ω Copper RTD

Supported temperature measurement ranges extend from approximately -200°C up to +870°C depending on sensor type.

Supported Thermocouple Types

Compatible thermocouple sensor types include:

• Type B

• Type E

• Type J

• Type K

• Type N

• Type R

• Type S

• Type T

• Type L (TXK/XK)

Measurement capability ranges from -270°C to +1800°C depending on thermocouple selection.

Input Signal Ranges

Data Formats

The module supports multiple engineering unit formats:

• Degrees Celsius (°C)

• Degrees Fahrenheit (°F)

• Kelvin (°K)

• Integer scaling values

• Resistance scaling

• Millivolt scaling

Performance Characteristics

Compatible Terminal Bases

The module can be installed with the following FLEX I/O terminal bases:

• 1794-TB3G

• 1794-TB3GS

• 1794-TB3GK

Included Components

• Two cold junction compensation sensors

• Integrated diagnostics circuitry

• FLEX I/O communication interface

Typical Applications

The Allen-Bradley 1794-IRT8 is commonly used in:

• Industrial furnace monitoring

• Process temperature control

• Chemical processing systems

• Food and beverage production lines

• Power generation plants

• Water treatment facilities

• Packaging and material handling systems

• HVAC automation systems

FAQ

What sensor types are compatible with the 1794-IRT8?

The module supports multiple RTD sensor types along with standard industrial thermocouples including J, K, T, E, R, S, B, and N.

Does the module provide channel isolation?

No. The 1794-IRT8 is a non-isolated analog input module.

What PLC platforms support this module?

The module is designed for Allen-Bradley FLEX I/O systems and can operate with ControlLogix, CompactLogix, PLC-5, and SLC systems through appropriate FLEX adapters.

How are wiring faults indicated?

The module includes eight red diagnostic LEDs that indicate open-input or sensor fault conditions for individual channels.