The 1794-IR8 is a high-density resistance temperature detector (RTD) input module serving as an integrated component within the FLEX I/O distributed network terminal matrix. This field-side hardware solution interfaces directly with diverse temperature elements to capture highly accurate thermal variations, executing precise analog-to-digital data conversions across an isolated backplane. By shifting conversion processes directly to remote processing junctions on standard DIN rails, the device reduces complex analog cable lengths back to central processing nodes, transmitting values over communication adapters including EtherNet/IP, ControlNet, and DeviceNet.
This industrial unit features eight non-isolated input channels configured to process two-wire, three-wire, or four-wire RTD sensors, as well as pure resistance sensor signals. The 1794-IR8 plugs directly into a standard compatible terminal base unit, drawing operational power and establishing bus backplane lines automatically upon connection. This assembly is standard across petrochemical refining facilities, plastic extrusion plants, power grid sub-stations, and commercial cold-storage installations requiring continuous multi-point ambient and medium thermal monitoring.
| Parameter | Specification |
|---|---|
| Manufacturer | Rockwell Automation / Allen-Bradley |
| Brand | FLEX I/O |
| Part Number | 1794-IR8 |
| Module Type | RTD Input Module |
| Number of Inputs | 8 Channels, Non-Isolated |
| Supported Sensor Types | 100, 200, 500, 1000 ohm Platinum; 120 ohm Nickel; 10 ohm Copper; 0 to 433 ohm Resistance |
| Resolution | 16-bit across full range |
| Accuracy | 0.1% of full scale |
| FlexBus Current Draw | 20 mA at 5V DC |
| External Power Supply | 24V DC nominal |
| Operational Voltage Range | 10V DC to 31.2V DC |
| Power Dissipation | 5.5 W maximum at 31.2V DC |
| Operating Temperature | 0 to 55 degC |
| Storage Temperature | -40 to 85 degC |
| Relative Humidity | 5% to 95% non-condensing |
| Country of Origin | USA |
| Approximate Weight | 0.09 kg |
| Approximate Dimensions | 46 mm x 94 mm x 53 mm |
| Terminal Block Connection (Typical 1794-TB3G) | Function |
|---|---|
| L(+) / L(-) | Ext. Power Supply 24V DC Input / Return Nodes |
| Channel 0 to Channel 7 Source | Current Excitation Source Terminals for RTD Sensors |
| Channel 0 to Channel 7 Sense (+) | Positive Differential Voltage Input Pins |
| Channel 0 to Channel 7 Return (-) | Negative Common Return Reference Connections |
Hook the top groove of the module enclosure under the upper lip of standard 35 mm DIN tracking. Apply continuous firm downward pressure on the lower half of the housing until the integrated spring-loaded retention tab snaps shut behind the bottom tracking bar.
Align the dual guide tracks of the electronic module with the matching alignment grooves on the pre-wired terminal base unit. Slide the device flush into the base socket matrix until the top and bottom latch bars snap outward into their locked configurations.
Run all RTD sensor circuits utilizing individual high-quality shielded twisted-pair cables. Terminate the overall copper braided shield drain wire explicitly at the dedicated functional chassis ground points built into the terminal base assembly.
Keep three-wire and four-wire sensor cable runs within official resistance tolerances to prevent adding lead-wire impedance offset values to the internal temperature computation register matrix.
What is the core function of this module assembly?
It provides an automated tracking interface that reads analog resistance values from RTD sensors and translates them into digital registers.
Can this unit handle two-wire and three-wire RTD sensors simultaneously?
Yes, each channel can be wired independently to match two-wire, three-wire, or four-wire probe layouts based on terminal configurations.
Are the individual instrumentation channels isolated from each other?
No, the eight measurement channels share a common internal reference within the conversion circuitry, though they are isolated from the main control bus.
How does the module deal with an open sensor wire fault?
The module sets an over-range status flag register for the damaged channel and outputs a specific value to indicate a broken sensor circuit.
Is it safe to pull this module off the rail while the main PLC is running?
Yes, it features removal and insertion under power capabilities, which allows engineers to perform field hot-swaps safely without disabling the network.
What terminal base units are compatible with this device?
The module is commonly paired with the 1794-TB3G, 1794-TB3GS, or 1794-TB32 terminal base units to manage the RTD signal wiring paths.
Does this device require a separate external power connection?
Yes, a nominal 24V DC external power source must be run to the terminal base block to power the internal sensor excitation and conversion matrices.
Can this device read raw ohm values instead of temperature parameters?
Yes, the channels can be software-configured to work in a pure resistance mode, measuring raw ohm values up to 433 ohms.
How is the sensor selection configured inside the system?
The target sensor material profile and wire configuration are designated by setting configuration parameters in the controller programming environment.
What is the digital conversion resolution of the measurement data?
The internal analog-to-digital converters process inputs using a precise 16-bit resolution matrix to deliver accurate temperature steps.
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Returns & Warranty
Manufacturer: Allen-Bradley
Product No.: 1794-IR8
Country of origin:United States
Product Type: RTD Input Module
Barcode: 8537101190
Payment: T/T, Western Union
Weight: 150g
Dimensions: 46 mm x 94 mm x 53 mm
Shipping port: Xiamen
Warranty: 12 months
The 1794-IR8 is a high-density resistance temperature detector (RTD) input module serving as an integrated component within the FLEX I/O distributed network terminal matrix. This field-side hardware solution interfaces directly with diverse temperature elements to capture highly accurate thermal variations, executing precise analog-to-digital data conversions across an isolated backplane. By shifting conversion processes directly to remote processing junctions on standard DIN rails, the device reduces complex analog cable lengths back to central processing nodes, transmitting values over communication adapters including EtherNet/IP, ControlNet, and DeviceNet.
This industrial unit features eight non-isolated input channels configured to process two-wire, three-wire, or four-wire RTD sensors, as well as pure resistance sensor signals. The 1794-IR8 plugs directly into a standard compatible terminal base unit, drawing operational power and establishing bus backplane lines automatically upon connection. This assembly is standard across petrochemical refining facilities, plastic extrusion plants, power grid sub-stations, and commercial cold-storage installations requiring continuous multi-point ambient and medium thermal monitoring.
| Parameter | Specification |
|---|---|
| Manufacturer | Rockwell Automation / Allen-Bradley |
| Brand | FLEX I/O |
| Part Number | 1794-IR8 |
| Module Type | RTD Input Module |
| Number of Inputs | 8 Channels, Non-Isolated |
| Supported Sensor Types | 100, 200, 500, 1000 ohm Platinum; 120 ohm Nickel; 10 ohm Copper; 0 to 433 ohm Resistance |
| Resolution | 16-bit across full range |
| Accuracy | 0.1% of full scale |
| FlexBus Current Draw | 20 mA at 5V DC |
| External Power Supply | 24V DC nominal |
| Operational Voltage Range | 10V DC to 31.2V DC |
| Power Dissipation | 5.5 W maximum at 31.2V DC |
| Operating Temperature | 0 to 55 degC |
| Storage Temperature | -40 to 85 degC |
| Relative Humidity | 5% to 95% non-condensing |
| Country of Origin | USA |
| Approximate Weight | 0.09 kg |
| Approximate Dimensions | 46 mm x 94 mm x 53 mm |
| Terminal Block Connection (Typical 1794-TB3G) | Function |
|---|---|
| L(+) / L(-) | Ext. Power Supply 24V DC Input / Return Nodes |
| Channel 0 to Channel 7 Source | Current Excitation Source Terminals for RTD Sensors |
| Channel 0 to Channel 7 Sense (+) | Positive Differential Voltage Input Pins |
| Channel 0 to Channel 7 Return (-) | Negative Common Return Reference Connections |
Hook the top groove of the module enclosure under the upper lip of standard 35 mm DIN tracking. Apply continuous firm downward pressure on the lower half of the housing until the integrated spring-loaded retention tab snaps shut behind the bottom tracking bar.
Align the dual guide tracks of the electronic module with the matching alignment grooves on the pre-wired terminal base unit. Slide the device flush into the base socket matrix until the top and bottom latch bars snap outward into their locked configurations.
Run all RTD sensor circuits utilizing individual high-quality shielded twisted-pair cables. Terminate the overall copper braided shield drain wire explicitly at the dedicated functional chassis ground points built into the terminal base assembly.
Keep three-wire and four-wire sensor cable runs within official resistance tolerances to prevent adding lead-wire impedance offset values to the internal temperature computation register matrix.
What is the core function of this module assembly?
It provides an automated tracking interface that reads analog resistance values from RTD sensors and translates them into digital registers.
Can this unit handle two-wire and three-wire RTD sensors simultaneously?
Yes, each channel can be wired independently to match two-wire, three-wire, or four-wire probe layouts based on terminal configurations.
Are the individual instrumentation channels isolated from each other?
No, the eight measurement channels share a common internal reference within the conversion circuitry, though they are isolated from the main control bus.
How does the module deal with an open sensor wire fault?
The module sets an over-range status flag register for the damaged channel and outputs a specific value to indicate a broken sensor circuit.
Is it safe to pull this module off the rail while the main PLC is running?
Yes, it features removal and insertion under power capabilities, which allows engineers to perform field hot-swaps safely without disabling the network.
What terminal base units are compatible with this device?
The module is commonly paired with the 1794-TB3G, 1794-TB3GS, or 1794-TB32 terminal base units to manage the RTD signal wiring paths.
Does this device require a separate external power connection?
Yes, a nominal 24V DC external power source must be run to the terminal base block to power the internal sensor excitation and conversion matrices.
Can this device read raw ohm values instead of temperature parameters?
Yes, the channels can be software-configured to work in a pure resistance mode, measuring raw ohm values up to 433 ohms.
How is the sensor selection configured inside the system?
The target sensor material profile and wire configuration are designated by setting configuration parameters in the controller programming environment.
What is the digital conversion resolution of the measurement data?
The internal analog-to-digital converters process inputs using a precise 16-bit resolution matrix to deliver accurate temperature steps.
| Product Image | Model Number / Title | Condition | Availability | Action |
|---|---|---|---|---|
|
Allen-Bradley 1794-OA8I FLEX I/O 8-Point Isolated AC Digital Output Module | Original New | In Stock | View Details |
Global Express Shipping
Returns & Warranty
Orders are processed and delivered Monday-Friday (excluding public holidays).
For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .
| Color pattern |
Greyish White
|
| Country of origin |
United States
|
| Power source |
DC Power
|
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