Product Overview

The Allen-Bradley 1794-IE8 is a high-performance 8-point analog input module designed for the FLEX™ I/O platform. This module serves as a versatile interface for converting real-world analog signals from field transmitters into digital data for PLC processing. It supports a wide array of signal configurations, including standard 4-20mA and 0-20mA current loops, as well as 0-10V DC and ±10V DC voltage ranges.

By utilizing a modular design, the 1794-IE8 attaches to a separate terminal base (such as the 1794-TB2 or 1794-TB3), which centralizes field wiring and allows for Removal and Insertion Under Power (RIUP). This feature is critical for industrial environments, enabling hardware maintenance or replacement without interrupting system power or disturbing existing terminations.

Advanced Signal Processing and Performance

The 1794-IE8 is engineered to deliver high-speed data acquisition with consistent thermal stability.

• Precision Conversion: Employs a successive approximation converter providing 12-bit unipolar resolution and 11-bit plus sign bipolar resolution for accurate signal representation.

• High-Speed Sampling: Features a rapid conversion rate of 256μs for all channels, ensuring minimal latency in dynamic process control loops.

• Flexible Input Selection: Software-configurable channels allow for a mix of voltage and current inputs to suit diverse sensor types.

• Rugged Reliability: Built to operate in temperatures ranging from -20°C to 55°C and designed to withstand up to 5g of vibration, making it suitable for mounting directly on machinery.

• Distributed Architecture: Seamlessly connects to EtherNet/IP, ControlNet, or DeviceNet networks via FLEX I/O adapters, reducing the need for long, expensive home-run cable pulls.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1794-IE8

• Number of Inputs: 8 Single-ended

• Input Ranges: 4-20 mA, 0-20 mA, ±10V DC, 0-10V DC

• Resolution: 12 bits (Unipolar); 11 bits + sign (Bipolar)

• Accuracy: 0.20% Full Scale @ 25°C

• External DC Power: 24V DC nominal (Range 10.5-31.2V DC)

• Backplane Current: 20mA @ 5V DC

• Input Impedance: 238 ohms (Current); 100k ohms (Voltage)

• Dimensions: 9.3 x 5.0 x 5.5 cm

• Weight: 0.12 kg (0.26 lbs)

Installation and Integration

The 1794-IE8 is a key component in the Rockwell Automation distributed I/O family. During installation, the module must be aligned with the Position 3 keyswitch on the terminal base to ensure correct mechanical and electrical mating. Its compact profile and DIN-rail mounting capability make it an ideal choice for high-density control cabinets where space is a premium.

For specialized environments where humidity or chemical exposure is a concern, conformal-coated versions of the 1794-IE8 are available to provide enhanced protection for the internal circuitry.