Product Overview
The Allen-Bradley 1794-IR8 is a Flex I/O analog input module specifically designed as a Resistance Temperature Detector (RTD) module for temperature applications. Part of the Rockwell Automation Flex I/O family, this module provides eight channels for accurate temperature measurement in demanding industrial environments. Engineers seeking reliable temperature sensing solutions will find this component essential for process control.
Technical Specifications Breakdown
Key parameters for the 1794-IR8 are listed below for quick reference:
| Feature | Specification |
|---|---|
| Number of Inputs | 8 Channels |
| Nominal Input Ranges | 1 to 433 ohms |
| Resolution | 16 bits across 435 ohms |
| RTD Excitation Current | 718.36 µA |
| Normal Mode Noise Rejection | -60 dB at 60 Hertz |
| Channel Bandwidth | 0 to 2.62 Hertz |
| Isolation Voltage | 850 Volts DC |
| Power Dissipation | 3 Watts at 31.2 Volts DC maximum |
| Thermal Dissipation | 10.2 BTU/hour at 31.2 Volts DC maximum |
| Operating Temperature | 0 to 55 C (32 to 131 F) |
| Storage Temperature | –40…85 °C (–40…185 °F) |
Industry Applications
With its 8-channel capacity and support for various RTD sensors (including 100 Ω Pt α = 0.00385 Euro and 100 Ω Pt α = 0.003916 U.S.), it enables precise temperature control across multiple zones. The 16-bit resolution ensures accurate data conversion, reducing measurement errors and improving process efficiency.
Installation & Setup Guidance
Mount the 1794-IR8 on a DIN rail using compatible terminal bases such as the 1794-TB2, 1794-TB3, or 1794-TB3T. Wire size is determined by the installed terminal base. Ensure the module is properly seated and locked into the base. Configure the data format as 16-bit 2's complement or offset binary (unipolar) to match your control system requirements. The system throughput is programmable from 28 ms/channel to 325 ms/channel in normal mode, allowing flexibility for different scan rates.
Maintenance & Reliability
To maintain optimal performance, inspect the module periodically for signs of environmental stress. The operating temperature range of 0 to 55 °C (32 to 131 °F) and storage temperature range of –40…85 °C (–40…185 °F) ensure reliability in varied conditions. The module withstands vibration up to 5g at 10 to 500 Hz and operating shock of 30 g, making it suitable for harsh industrial environments.
Compatibility & Integration
It supports a wide range of RTD sensors, including platinum (Pt), nickel, and copper types, with specific temperature ranges as detailed in the specifications. This compatibility simplifies system design and reduces inventory complexity.
Selection Guide & Purchasing Advice
When selecting the 1794-IR8 for your application, consider the number of RTD inputs needed and the sensor types you plan to use. For purchasing, please verify current lifecycle status and availability with AutoDCSTech before ordering. Our team can assist with compatibility questions and ensure you receive genuine Allen-Bradley components.
Troubleshooting & Common Issues
If the module does not communicate with the control system, check the FlexBus connection and ensure the terminal base is properly installed. Verify that the RTD excitation current of 718.36 µA is within expected range for your sensors. For inaccurate readings, confirm the data format setting (16-bit 2's complement or offset binary) matches the controller configuration. Noise issues may be mitigated by the normal mode noise rejection of -60 dB at 60 Hertz.
Availability & Condition at AutoDCSTech
| Part Number | 1794-IR8 |
|---|---|
| Availability | In Stock |
| Condition | New |
| Warranty | One Year |
| Origin | US |
