PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1794-IJ2 is a FLEX I/O Frequency Input Module designed for industrial measurement systems. It operates on an external DC supply ranging from 19.0 to 31.2V DC. The unit provides two frequency input channels and two isolated outputs. It accepts sine wave and square wave input signals up to 32 kHz. The device connects directly through standard terminal bases such as 1794-TB3G or 1794-TB3GS.
Each output channel delivers up to 1.0 A current at 24V DC nominal voltage. The outputs support assignments for frequency monitoring, percent full scale, or acceleration alarms. Both inputs and outputs are electrically fused to prevent damage during power supply interruptions. The module draws 30 mA from the FlexBus backplane at 5V DC. Operating temperatures range from 0 to 55 degrees Celsius in standard industrial environments.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
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| Product Line | Flex I/O 1794 |
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| UPC | 612598180219 |
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| Weight | 0.56 lbs (0.26 kg) |
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| Power Dissipation | 4.6W maximum at 31.2V DC |
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| Input Frequency | 1-32 kHz w/sine wave; 1-32 kHz w/square wave input |
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| Thermal Dissipation | Maximum 15.6 BTU/hr at 31.2V DC |
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| Product Description | Flex IO Frequency Input Module |
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| No. of inputs | Two (2); Frequency; Two (2) Frequency and gate per channel |
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| No. of Outputs | Two (2) 24VDC |
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| Raw Frequency Value | Maximum 32,767 or 3,276.7 (dependent on range) |
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| Input Pulse Width | 20 ?s |
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| Output Voltage, min | 10VDC |
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| Output Voltage, Nom | 24VDC |
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| Terminal base | 1794-TB3G or -TB3GS. |
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| External DC supply range | 19.0…31.2V DC (includes 5% AC ripple) |
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| FlexBus Current | 30 mA at 5V DC |
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| Mounting | DIN Rail |
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| Wire Size | Determined by installed terminal base |
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| Inputs | 2 per Channel |
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| On-state Voltage min. | 10V |
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| On-state Current nom. | 9.0mA |
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| Outputs | 2 Isolated |
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| Output Off-state Voltage max. | 31.2V DC |
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| Output On-state Current | 1.0A per Channel max. |
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TECHNICAL INFORMATION
Features
- Processes sine wave and square wave frequency inputs up to 32 kHz.
- Provides two isolated 24V DC output channels rated at 1.0 A each.
- Configurable output channels trigger on frequency, percent full scale, or acceleration.
- Output switching provides a 0.5 ms turn-on time and 1 ms turn-off time.
- Front panel indicators display input, output, wire-off fault, and power status.
TECHNICAL INFORMATION
Applications
- Processes measuring physical acceleration.
- Systems requiring high-speed directional measurement.
- Applications reporting frequency values at specific points in time.
- FLEX I/O stations performing frequency and acceleration alarm monitoring.
TECHNICAL INFORMATION
Connections / Interfaces
- Mounts directly onto 1794-TB3G or 1794-TB3GS terminal base units.
- Communicates across the FlexBus backplane using an inserted backplane connector.
- Accepts external field wiring specified by the chosen terminal base unit.
TECHNICAL INFORMATION
Installation Guidelines
- Firmly insert the module into the terminal base until locked in place.
- Verify the FlexBus connector is fully engaged with adjacent terminal units.
- Mount the assembly on DIN rail or use 1794-NM1 mounting screws.
- Maintain ambient operating temperatures between 0 and 55 degrees Celsius.
TECHNICAL INFORMATION
Configuration Guidelines
- Configure module operating parameters through the adapter communication link.
- Select sample frequency periods ranging between 2 ms and 1000 ms.
- Assign individual output channels to frequency, full scale, or acceleration alarms.
TECHNICAL INFORMATION
Compatibility
- Compatible with Allen-Bradley FLEX I/O communication adapters including Ethernet and PROFIBUS units.
- Requires a 1794-TB3G or 1794-TB3GS terminal base for operation.
TECHNICAL RESOURCES
Documentation
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSCompatible with Allen-Bradley FLEX I/O communication adapters including Ethernet and PROFIBUS units. Requires a 1794-TB3G or 1794-TB3GS terminal base for operation.
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 is the primary function of the 1794-IJ2 module?
The module processes high-speed frequency inputs and executes acceleration or threshold alarm monitoring.
Which terminal bases are compatible with the 1794-IJ2?
The 1794-IJ2 mounts on Allen-Bradley 1794-TB3G and 1794-TB3GS terminal base units.
What input frequency range does the module support?
The module accepts sine and square wave inputs from 1 Hz up to 32 kHz.
What is the indicative reference price for the 1794-IJ2?
Observed market reference pricing is approximately 289 USD. Figures are indicative market reference pricing only and are not a final quotation.
