PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1794-IE8H is an eight-channel analog input module for the FLEX I/O system. This module interfaces with Highway Addressable Remote Transducer devices over 4 to 20 milliamp loops. It provides 16-bit unipolar or 15-bit bipolar resolution across eight single-ended, non-isolated input channels. Internal successive approximation conversion delivers digitized process measurements. The unit operates with an absolute accuracy of 0.1 percent at 20 degrees Celsius.
External power connects through a 24-volt direct current nominal supply across 19.0 to 31.2 volts. The module consumes 80 milliamps at 5 volts direct current from the FlexBus backplane. Field-side circuits are isolated from the system bus at 50 volts continuous basic insulation. Onboard diagnostics detect lead breakage, remote transmitter status, and over-range or under-range conditions. Visual indicators include eight red fault LEDs, eight yellow channel LEDs, and one green power LED.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
|---|
| Product Line | Flex I/O 1794 |
|---|
| UPC | 612598323883 |
|---|
| Weight | 0.06 lbs (0.03 kg) |
|---|
| Resolution | 16 bits |
|---|
| Conversion Type | Successive Approximation |
|---|
| Product Description | Flex IO HART Module |
|---|
| No. of inputs | Eight (8) Single Ended; non-isolated |
|---|
| Absolute accuracy | 0.1% Full Scale @ 20 °C (68°F) |
|---|
| Accuracy drift with temperature | 0.05% Full Scale for 0 °C...55 °C (32...131 °F) |
|---|
| Step Response to 99% | 80 ms |
|---|
| Terminal base | 1794-TB3G and 1794-TB3GS |
|---|
| Indicators | 8 red fault indicators, 8 yellow channel indicators and 1 green for power. |
|---|
| External DC supply, nom | 24V DC |
|---|
| External DC supply range | 19.0 to 31.2V DC (includes 5% AC ripple) |
|---|
| Mounting | DIN Rail |
|---|
| Wire Size | Determined by installed terminal base |
|---|
| Inputs | 8 Single-ended |
|---|
| Data Format | Configurable |
|---|
| Functional Data Range | >17V @ 22mA |
|---|
| FlexBus Current External Input | 5V DC 80mA |
|---|
| Enclosure Type Rating | None (open-style) |
|---|
| Isolation Voltage | 50V Continuous |
|---|
| Power Dissipation | 3.9W @ 31.2V DC max. |
|---|
| Thermal Dissipation | 13.5 BTU/hr. @ 31.2V DC |
|---|
TECHNICAL INFORMATION
Features
- Supports Highway Addressable Remote Transducer protocol communication on 4 to 20 mA loops.
- Provides eight single-ended analog input channels with selectable digital filtering.
- Delivers 16-bit unipolar and 15-bit bipolar resolution via successive approximation conversion.
- Includes local microprocessor intelligence for transmitter error sensing and lead breakage detection.
- Features seventeen diagnostic status LEDs for power, channel activity, and individual channel faults.
- Operates without hardware jumpers or configuration switches.
TECHNICAL INFORMATION
Applications
- Process control monitoring using HART pressure, temperature, and flow transmitters.
- Distributed analog signal acquisition in industrial FLEX I/O remote racks.
- Continuous current-loop monitoring across 0 to 20 mA and 4 to 20 mA field circuits.
TECHNICAL INFORMATION
Connections / Interfaces
- Connects to the FLEX I/O backplane via the terminal base FlexBus interface.
- Field wiring lands directly on compatible terminal base unit connection points.
TECHNICAL INFORMATION
Installation Guidelines
- Snap the module onto an installed 1794-TB3G or 1794-TB3GS terminal base unit.
- Mount the terminal base assembly securely on standard 35 mm DIN rail.
- Wire external 24-volt direct current power observing polarity guidelines.
- Maintain adequate spacing inside the industrial enclosure for convective cooling.
TECHNICAL INFORMATION
Configuration Guidelines
- Select input signal ranges and filter cutoff settings via control software.
- Configure transmitter error thresholds and alarm trip points digitally.
- Verify adapter firmware matches the module profile before commissioning.
TECHNICAL INFORMATION
Compatibility
- Mounts on terminal base units catalog numbers 1794-TB3G and 1794-TB3GS.
- Works with ControlNet network adapters running firmware revision 5.1 or greater.
- Compatible with EtherNet/IP adapters running firmware revision 4.2 or greater for Series B profiles.
- Connects to PROFIBUS networks using adapter catalog number 1794-APBDV1.
TECHNICAL RESOURCES
Documentation
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSMounts on terminal base units catalog numbers 1794-TB3G and 1794-TB3GS. Works with ControlNet network adapters running firmware revision 5.1 or greater. Compatible with EtherNet/IP adapters running firmware revision 4.2 or greater for Series B profiles. Connects to PROFIBUS networks using adapter catalog number 1794-APBDV1.
Verify compatibility against the exact Part Number, revision and manufacturer documentation before ordering.
PART VERIFICATION
Before You Order
Industrial automation parts can share similar model names, suffixes and revisions. Confirm the complete manufacturer Part Number before purchase.
01Check Part NumberMatch the complete ordering code on the existing unit.
02Confirm RevisionCheck suffix, hardware or firmware when applicable.
03Send a Label PhotoWe can review a clear label photo when identification is uncertain.
ORDERING PROCESS
From RFQ to Dispatch
1Submit Part Number2Verify Product Identity3Confirm Stock & Condition4Issue Quotation5Dispatch & Tracking
PRODUCT FAQ
Frequently Asked Questions
What communication protocol does the Allen-Bradley 1794-IE8H support?
The module supports the Highway Addressable Remote Transducer protocol across 4 to 20 mA instrumentation loops.
Which terminal base units are compatible with the 1794-IE8H?
The 1794-IE8H mounts onto Allen-Bradley terminal base units 1794-TB3G and 1794-TB3GS.
What input signal ranges does the 1794-IE8H accept?
The module accepts 0 to 20 mA and 4 to 20 mA analog input signals.
What resolution does the 1794-IE8H provide?
It delivers 16-bit unipolar resolution and 15-bit bipolar resolution across eight channels.
What diagnostic fault detection is available on the 1794-IE8H?
The unit detects lead breakage, remote transmitter alarms, and input over-range or under-range conditions.
