The Allen-Bradley 1794-IF8IH is an 8-channel isolated HART analog input module for the FLEX I/O system. It provides 8 individually isolated current inputs (0–20 mA or 4–20 mA) with 16-bit resolution and HART 5/6/7 pass-through communication, enabling remote configuration, calibration, and diagnostics of HART-enabled transmitters without additional multiplexers.
Item No :
1794-IF8IHOrder(MOQ) :
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EXWProduct Origin :
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WuhanLead Time :
3~5 daysWeight :
5kg| Specification | Description |
|---|---|
| Manufacturer | Rockwell Automation (Allen-Bradley) |
| Model | 1794-IF8IH |
| Product Family | FLEX I/O |
| Product Type | Isolated HART Analog Input Module |
| Number of Inputs | 8 isolated, single-ended |
| Input Signal Range | 0–20 mA or 4–20 mA (configurable per channel) |
| Resolution | 16-bit unipolar; 15-bit plus sign bipolar |
| Accuracy | ±0.1% full scale @ 25°C |
| Conversion Type | Sigma-Delta |
| Isolation | 120V continuous (basic insulation); type tested @ 1000V AC for 60s between channel and system |
| HART Communication | HART 5, 6, 7 pass-through; one HART modem per channel |
| Step Response | 4 ms to 99% full scale @ 470 Hz conversion rate |
| External DC Power | 24V DC (19.2–31.2V DC) |
| FlexBus Current | 80 mA @ 5V DC |
| Power Dissipation | 4.8W max @ 31.2V DC |
| Thermal Dissipation | 16.4 BTU/hr max |
| Isolation Voltage | 120V continuous; type tested @ 1000V AC |
| Terminal Base | 1794-TB3, 1794-TB3S |
| Operating Temperature | 0°C to +55°C |
| Storage Temperature | -40°C to +85°C |
| Dimensions (H x W x D) | 94 x 94 x 66 mm (3.7 x 3.7 x 2.6 in.) |
| Weight | Approx. 0.4 kg |
| Certifications | ATEX, UKEX, CCC, RINA (marine) |
| Lifecycle Status | Active / Mature |
| Model | Description | Typical Application |
|---|---|---|
| 1794-IF8IH (this model) | 8-ch isolated HART analog input module | Process control with smart transmitters |
| 1794-IF8IHNFXT | Conformal-coated, extended temperature version (-25 to +70°C) | Harsh environments requiring wide temperature |
| 1794-OF8IH | 8-ch isolated HART analog output module | HART valve positioner control |
| 1794-IE8H | 8-ch HART analog input module (earlier version) | Legacy HART input applications |
| 1794-TB3 | Terminal base for HART analog modules | Required mounting base |
| 1794-TB3S | Terminal base with spring terminals | Alternative mounting base |
| 5094-IF8IH | FLEX 5000 8-ch isolated HART analog input | Migration path for new installations |
| 1734-IE8CH | POINT I/O 8-ch HART analog input | Alternative platform for distributed I/O |
Q1: What is the primary function of the 1794-IF8IH?
It is an 8-channel isolated HART analog input module for the FLEX I/O system. It accepts 0–20 mA or 4–20 mA current signals from field transmitters while simultaneously enabling HART digital communication over the same two wires. This allows the controller to read process variables, access device diagnostics, and reconfigure smart transmitters without additional HART multiplexer hardware .
Q2: Does the 1794-IF8IH 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 is recommended to minimize interference with the HART communication frequency . The module uses a 1794-TB3 or 1794-TB3S terminal base for wiring .
Q3: What is the difference between the 1794-IF8IH and the 1794-IF8IHNFXT?
The 1794-IF8IHNFXT is the conformal-coated, extended temperature version of the same module. It operates over a wider temperature range (-25°C to +70°C) compared to the standard 1794-IF8IH (0°C to +55°C), and features conformal coating for protection against moisture, dust, and corrosive elements . Both provide 8 isolated HART analog inputs and are functionally equivalent in standard environments.
Q4: Is the 1794-IF8IH still in production?
The status is mixed. Some suppliers list it as Active / Available from OEM , while other sources indicate it is a mature product with a recommended replacement path to the 1734-IE8CH (POINT I/O) or FLEX 5000 platform. For new installations, Rockwell Automation may recommend migration to the FLEX 5000 platform (5094-IF8IH). Existing installations remain supported.
Q5: What are the common applications for the 1794-IF8IH?
It is widely used in process control applications including pressure/flow/temperature multi-variable acquisition, HART flow meter integration, predictive maintenance of smart valve positioners, and pharmaceutical applications requiring data traceability. The module's HART capability enables remote diagnostics and configuration of smart field instruments without handheld communicators.
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The Allen-Bradley 1794-IF8IH is an 8-channel isolated HART analog input module for the FLEX I/O system. It provides 8 individually isolated current inputs (0–20 mA or 4–20 mA) with 16-bit resolution and HART 5/6/7 pass-through communication, enabling remote configuration, calibration, and diagnostics of HART-enabled transmitters without additional multiplexers.
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