Allen-Bradley 1794-IE8H HART Analog Input Module Overview

The Allen-Bradley 1794-IE8H is a HART-capable analog input module for Flex I/O systems. This module features eight non-isolated, single-ended analog input channels. The Allen-Bradley 1794-IE8H supports analog signal ranges of 0-20 mA and 4-20 mA. It supports the Highway Addressable Remote Transducer (HART) communication protocol. This high resolution module is capable of both bipolar and unipolar configuration. The Allen-Bradley 1794-IE8H has a local microprocessor for handling advanced features. It functions without switches or jumpers for easy setup.

Technical Specifications

General Specifications

• Manufacturer: Rockwell Automation.

• Brand: Allen-Bradley.

• Part Number: 1794-IE8H.

• Product Type: Flex I/O HART Analog Module.

• Product Description: Flex IO HART Module.

• Number of Inputs: 8 single-ended, non-isolated.

• Resolution: 16 bits (unipolar); 15 bits (bipolar).

• Conversion Type: Successive Approximation.

• UPC: 10612598323880.

Input Signal Ranges

• Analog Signal Ranges: 0-20 mA and 4-20 mA.

• Default Input Range: 0 to 20 mA.

• Functional Data Range: >17V at 22 mA; >23V at 0 mA.

Accuracy Specifications

• Absolute Accuracy: 0.1% Full Scale at 20°C (68°F).

• Accuracy Drift with Temperature: 0.05% Full Scale for 0°C to 55°C (32°F to 131°F).

Performance Specifications

• Step Response to 99%: 80 ms.

• Voltage Variation: 10 ms interruption on DC supply ports.

• Selectable Filters: Yes.

Power Specifications

• External DC Supply (nominal): 24V DC.

• External DC Supply Range: 19.0 to 31.2V DC (includes 5% AC ripple).

• Nominal External DC Supply Current: 295 mA at 24V DC.

• FlexBus Current (5V DC): 80 mA.

• FlexBus Current (24V DC): 190 mA.

• Power Dissipation: 3.9W at 31.2V DC maximum.

• Thermal Dissipation: 13.5 BTU/hr at 31.2V DC.

Isolation Specifications

• Isolation Voltage: 50V continuous (between field side and system).

• Insulation Type: Basic Insulation Type.

• Routine Test: 850V DC for 1 second.

• Channel to Channel Isolation: No isolation between channels.

Status Indicators

The Allen-Bradley 1794-IE8H includes:

• 8 red fault indicators (one per channel)

• 8 yellow channel indicators (one per channel)

• 1 green power indicator

Alarm and Detection Features

• Lead breakage detection

• Overrange and underrange alarms

• Remote transmitter alarm

• Configurable high/low error levels

Configurable Features

• Input filter cutoff

• Fault mode

• Data format

• High/low error level

• Remote transmitter error correcting

Compatible Terminal Bases

The Allen-Bradley 1794-IE8H requires:

• 1794-TB3G

• 1794-TB3GS

Compatible Communication Adapters

• ControlNet adapters (revision 5.1 or greater for Series B)

• Ethernet adapters (revision 4.2 or greater for Series B)

• ProfiBus adapter (catalog number 1794-APBDV1 only)

Environmental Specifications

• Operating Temperature: -20°C to 55°C.

• Non-Operating Temperature: -40°C to 85°C.

• Operating Vibration: 2 g at 10 to 500 Hz.

• Operating Shock: 15 g.

• Non-Operating Shock: 15 g.

• Enclosure Type Rating: None (open-style).

• Mounting: DIN Rail.

• Wire Size: Determined by installed terminal base.

Physical Specifications

• Product Net Weight: 0.32 kg.

• Gross Weight: 0.52 kg (with packaging).

Installation Guide

Follow these steps to install the Allen-Bradley 1794-IE8H correctly:

1. Turn off all power to the Flex I/O system before installation.

2. Insert the Allen-Bradley 1794-IE8H into a compatible terminal base (1794-TB3G or 1794-TB3GS).

3. Connect external 24V DC power (19.0 to 31.2V DC range) to the module.

4. Wire 4-20 mA or 0-20 mA analog sensors to the 8 single-ended input channels.

5. Configure the input range and data format using your programming software.

6. Set up input filter cutoff and fault mode parameters as needed.

7. Verify HART communication with connected field devices.

8. Test the Allen-Bradley 1794-IE8H by monitoring channel indicators and fault LEDs.

Packaging List

• Allen-Bradley 1794-IE8H HART analog input module (1 unit)

• Anti-static protective bag (1 piece)

• Installation instructions manual (1 copy)

• Product label with catalog number

Frequently Asked Questions (FAQ)

1. What signal ranges does the 1794-IE8H support?
The Allen-Bradley 1794-IE8H supports 0-20 mA and 4-20 mA analog signal ranges.

2. Does this module support HART communication?
Yes, the 1794-IE8H supports the HART protocol for communicating with smart instrumentation.

3. What terminal bases are compatible with the 1794-IE8H?
This module requires terminal bases 1794-TB3G or 1794-TB3GS for installation.

4. What is the resolution of the 1794-IE8H?
The module provides 16-bit resolution for unipolar signals and 15-bit resolution for bipolar signals.

5. What alarms does the 1794-IE8H provide?
This module provides lead breakage detection, overrange/underrange alarms, and remote transmitter alarm.