Product Summary
The Allen-Bradley 1794-IRT8 Flex I/O module provides eight versatile input channels. This unit supports both RTD and thermocouple sensors for flexible system design. Engineers can select from multiple data formats including Celsius, Fahrenheit, and Kelvin. The module delivers high accuracy with a 14-bit resolution for critical temperature monitoring.
Product Procurement & Buyer Guide
Understanding the 1794-IRT8 Module
The 1794-IRT8 serves as a combination input module within the Flex I/O system. It accepts signals from resistance temperature detectors and thermocouples. This unit connects directly to a terminal base and power adapter. You must order the terminal base separately for your installation. The module ships with two cold junction compensators for enhanced thermocouple accuracy.
Key Technical Specifications
This module operates on a nominal 24 Volts DC power supply. It groups its eight channels into two sets of four inputs each. The RTD input range spans 0 to 325 mV for accurate resistance measurement. Thermocouple inputs accept a nominal range of -40 to 100 mV DC. The module achieves a resolution of 14 bits for precise data conversion.
Supported Sensor Types
The unit supports a wide variety of RTD sensors for global applications. You can connect 100 Ohm platinum RTDs with European or US curves. Nickel and copper RTDs also work with this versatile input module. For thermocouples, the module accepts Types B, E, J, K, L, N, R, S, and T. This broad compatibility simplifies procurement for multi-sensor installations.
Data Format Selection
You can configure the module to output temperature in several engineering units. Selectable formats include °C (XXX.X), °F (XXX.X), or °K (XXX.X). The module also supports raw data formats for custom applications. These include -32767 to +32767 and 0 to 65535 integer ranges. For ohms mode, use the 0 to 5000 range with an implied decimal point.
System Throughput Performance
The module processes signals at different speeds depending on the sensor type. Millivolt mode achieves a fast throughput time of just 7.4 milliseconds. RTD measurements take between 8.0 and 10.8 milliseconds based on wire configuration. Thermocouple readings complete in 8.0 to 8.8 milliseconds. This performance suits most industrial process control applications.
Installation and Wiring Guidance
Mount the module on a standard DIN rail for secure installation. Use thermocouple extension wire as specified by the sensor manufacturer. For millivolt signals, Belden 8761 cable provides reliable performance. The module operates within a temperature range of 0 to 55 degrees Celsius. It withstands vibration up to 5g at frequencies from 10 to 500 Hz.
Diagnostic and Protection Features
The module includes embedded open circuit detection for system reliability. When a sensor fault occurs, the reading upscales to a maximum value. This behavior applies to both RTD and thermocouple operating modes. The open input detection time spans two complete scan cycles. The unit also handles overvoltage conditions up to 15V DC continuous at 25 degrees Celsius.
Logistics & Standard Packaging Details
- One Allen-Bradley 1794-IRT8 Flex I/O RTD/Thermocouple Input Module
- Two cold junction compensators for thermocouple accuracy enhancement
- Removable user-customizable label for field identification
- Nameplate identifying the module part number and specifications
- Compatible with terminal bases 1794-TB3G, 1794-TB3GS, and 1794-TB3GK
- Express delivery shipping is available via FedEx, UPS, and DHL
