The Allen-Bradley 1794-OE8H is an 8-channel HART analog output module for the FLEX I/O system, designed for process control applications requiring direct communication with smart field devices. It provides 0–20 mA or 4–20 mA current outputs on each channel while simultaneously enabling HART digital communication over the same two wires, eliminating the need for external HART multiplexers or additional wiring.
Item No :
1794-OE8HOrder(MOQ) :
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EXWProduct Origin :
Singapore/ChinaShipping Port :
WuhanLead Time :
3~5 daysWeight :
5kg| Specification | Description |
|---|---|
| Manufacturer | Rockwell Automation (Allen-Bradley) |
| Model | 1794-OE8H |
| Product Family | FLEX I/O |
| Product Type | HART Analog Output Module |
| Number of Outputs | 8 single-ended, non-isolated |
| Output Current Range | 0–20 mA or 4–20 mA (configurable per channel pair) |
| Resolution | 13 bits |
| Accuracy | 0.1% full scale @ 20°C |
| Temperature Drift | 0.010% full scale for 0–55°C |
| Conversion Type | Sigma-delta |
| Step Response | 4 ms to 99% of full scale (current) |
| HART Communication | Yes — FSK modulation over 4–20 mA loop |
| Isolation | 50V continuous (basic insulation); no channel-to-channel isolation |
| Power Supply | 24V DC (19.2–31.2V DC) |
| Power Dissipation | 6.1W max @ 31.2V DC |
| Indicators | 8 red fault LEDs; 8 yellow HART LEDs; 1 green power LED |
| Terminal Base | 1794-TB3G or 1794-TB3GS |
| Operating Temperature | 0°C to +55°C |
| Lifecycle Status | End of Life (Discontinued March 31, 2026) |
| Model | Description | Typical Application |
|---|---|---|
| 1794-OE8H (this model) | 8-ch HART analog output, 0/4–20 mA | Process control with smart valve positioners |
| 1794-OE4 | 4-ch analog output, 0/4–20 mA (non-HART) | Standard analog output applications |
| 1794-OE12 | 12-ch analog output, 0/4–20 mA (non-HART, higher density) | High-density analog control without HART |
| 1794-IE8H | 8-ch HART analog input module | HART input companion for the OE8H |
| 1794-IF8IH | 8-ch isolated HART analog input | Isolated HART input applications |
| 1794-OF8IH | 8-ch isolated HART analog output (higher isolation) | Applications requiring channel isolation |
| 5094-OF8IH | Recommended replacement — 8-ch isolated HART analog output, FLEX 5000 | Migration path for discontinued 1794-OE8H |
| 1794-TB3G | Terminal base for HART analog modules | Required mounting base for OE8H |
Q1: What is the primary function of the 1794-OE8H?
It is an 8-channel HART analog output module for the FLEX I/O system. It provides 0–20 mA or 4–20 mA current outputs to control field actuators such as valves and positioners, while simultaneously enabling HART digital communication over the same wiring for configuration, calibration, and diagnostics of smart field devices .
Q2: Does the 1794-OE8H require special wiring for HART communication?
No. HART digital signals are superimposed on the standard 4–20 mA analog current using Frequency Shift Keying (FSK). The same two wires carry both the analog control signal and the digital HART data. Shielded twisted-pair cable (such as Belden 9463 or equivalent) is recommended to minimize interference with the HART communication frequency .
Q3: What is the difference between the 1794-OE8H and the 1794-OE12?
The 1794-OE8H has 8 output channels with HART capability. The 1794-OE12 has 12 output channels without HART. The OE8H is designed for applications requiring smart device diagnostics and configuration, while the OE12 is optimized for maximum channel density in standard analog control applications .
Q4: Is the 1794-OE8H still in production?
No. The 1794-OE8H was discontinued by Rockwell Automation as of March 31, 2026 . It is now available through aftermarket suppliers, surplus stock, and refurbished units. The official replacement is the 5094-OF8IH from the FLEX 5000 platform, which offers isolated channels and improved diagnostic capabilities.
Q5: What are the common applications for the 1794-OE8H?
It is widely used in process control applications including valve positioner control (with HART diagnostics for predictive maintenance), analog signal output to final control elements, remote I/O applications in distributed control systems, and any application where HART smart device management is required without additional multiplexer hardware.
The Allen-Bradley 1794-OE4 is a 4-channel analog output module for the FLEX I/O system. It provides 4 single-ended, non-isolated outputs with software-selectable voltage (±10V, 0–10V) or current (0–20 mA, 4–20 mA) ranges, offering 12-bit plus sign resolution and 1.024 ms conversion rate for all channels.
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The Allen-Bradley 1794-OE8H is an 8-channel HART analog output module for the FLEX I/O system, designed for process control applications requiring direct communication with smart field devices. It provides 0–20 mA or 4–20 mA current outputs on each channel while simultaneously enabling HART digital communication over the same two wires, eliminating the need for external HART multiplexers or additional wiring.
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