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  3. ALLEN BRADLEY 1797-1J2

ALLEN-BRADLEY 1797-1J2 Flex Ex Frequency Module 3A-30

1797-1j2 Allen-bradley Flex Ex Frequency Input Module 3a-30

( Brand: Allen-bradley ), ( Manufacturer Part Number: 1797-1J2 ), ( Type: Plc Output Module ), ( Analog/digital: Analog ), ( Controller Platform: Compactlogix )

Review ALLEN BRADLEY Flex Ex Frequency Input Module

The **Allen-Bradley 1797-1J2 Flex I/O Frequency Module (3A 30V AC)** is a high-performance, compact frequency input module designed to integrate seamlessly into Allen-Bradley s Flex I/O system, providing reliable and precise analog signal processing for industrial automation applications. This module is engineered to accept a wide range of frequency-based signals, making it ideal for monitoring variable frequency drives (VFDs), encoders, pulse generators, or other frequency-modulated devices where accurate speed, position, or process control is critical. With a robust input range of **3A 30V AC**, the module is capable of handling signals from various industrial sensors and transducers, ensuring compatibility with a broad spectrum of automation systems. Its **1797 series** architecture delivers high-speed data acquisition and deterministic performance, minimizing latency and maximizing efficiency in real-time control environments. The module features **isolated inputs** for enhanced safety and noise immunity, protecting against electrical interference that could compromise signal integrity in harsh industrial settings. Built with Allen-Bradley s reputation for durability, the 1797-1J2 is constructed to withstand demanding operational conditions, including temperature fluctuations, vibration, and electrical surges, ensuring long-term reliability in factory floors, manufacturing plants, and process control systems. Its modular design allows for easy integration into existing Flex I/O backplanes, simplifying system expansion and maintenance while reducing downtime. Whether used for speed monitoring, process optimization, or closed-loop control, this frequency module provides engineers with a versatile and dependable solution for capturing and processing high-frequency signals with exceptional accuracy and consistency.

The **Allen-Bradley 1797-1J2 Flex Ex Frequency Module (3A 30V)** is a frequency inverter designed for use in hazardous areas (ATEX/IECEX certified) with a rated output current of 3A and a voltage range of 30V. Below is a detailed analysis of its pros and cons, followed by a conclusion and recommendation.

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### **Pros**

1. **Explosion-Proof Certification (ATEX/IECEX)**

The module is certified for use in hazardous environments (Zone 1/2, Division 1/2), making it suitable for industries like oil and gas, chemical processing, or mining where flammable gases or dust are present. This eliminates the need for additional explosion-proof enclosures or remote control schemes, reducing installation complexity and cost.

2. **Compact and Modular Design**

The 1797 series is part of Rockwell Automation s Flex Ex family, which is designed for easy integration into existing control systems. The module s small footprint allows for space-efficient installation, especially in crowded control panels or hazardous area cabinets.

3. **Compatibility with Rockwell Automation Ecosystem**

It integrates seamlessly with **ControlLogix, CompactLogix, and Studio 5000** platforms, leveraging Rockwell s programming environment (Ladder Logic, Structured Text, etc.). This reduces development time and simplifies troubleshooting compared to third-party inverters that may require proprietary software.

4. **Wide Input Voltage Range (30V 300V DC)**

The module supports a broad input voltage range, providing flexibility in power supply configurations. This is particularly useful in applications where voltage fluctuations are common or where multiple devices share a common DC bus.

5. **Digital Communication Protocols**

The 1797-1J2 supports **DeviceNet, EtherNet/IP, and Modbus** (depending on the variant), enabling advanced monitoring, control, and diagnostics. This is valuable for implementing predictive maintenance or remote operation in hazardous areas.

6. **High Reliability and Redundancy Options**

Rockwell Automation products are known for their robustness and long-term availability. Some variants in the Flex Ex series offer redundancy features (e.g., dual-channel operation), improving system uptime in critical applications.

7. **Low Voltage Output (3A 30V)**

The 30V output is suitable for driving low-power motors, pumps, or actuators in hazardous areas where higher voltages (e.g., 480V) are impractical due to safety or space constraints. This makes it ideal for applications like gas compressors, valve actuators, or small conveyors.

8. **Intrinsic Safety (IS) Capability**

The module can be configured for intrinsic safety circuits, further reducing the risk of ignition in explosive atmospheres. This is a key advantage over non-certified inverters that require additional isolation barriers.

9. **Easy Installation and Wiring**

The module features **screw-terminal connections** and clear labeling, simplifying field wiring. The Flex Ex series is designed to be installed directly in hazardous area enclosures without additional shielding.

10. **Support for Variable Frequency Drives (VFD) Applications**

The 1797-1J2 can control motor speed and torque, enabling energy savings and extended equipment life. This is useful for applications like fans, pumps, or mixers where variable speed control is beneficial.

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### **Cons**

1. **Limited Current Rating (3A)**

The 3A output current severely restricts its use to **low-power applications only**. For motors or loads requiring higher current (e.g., 10A or above), this module is **not suitable**, and a larger inverter (e.g., 1797-2J2 for 6A or 1797-3J2 for 10A) would be necessary. This limitation may require additional inverters or parallel operation, increasing complexity and cost.

2. **Higher Cost Compared to Non-Explosion-Proof Alternatives**

The ATEX/IECEX certification and Rockwell s branding come at a premium. For non-hazardous applications, standard **non-certified inverters** (e.g., Danfoss VLT, Siemens Micromaster) would be significantly cheaper while offering similar performance.

3. **Voltage Limitations**

The **30V output** is very low, which may not be practical for many industrial motors (typically rated for 230V, 400V, or 480V). This restricts its use to **small, low-voltage motors or specialty actuators**. For standard three-phase motors, a step-up transformer or a different inverter would be required.

4. **Limited Overload and Short-Circuit Protection**

While the module has built-in protection, its **3A rating means it cannot handle sustained overloads** without tripping. For applications with high starting currents (e.g., pumps with long lead wires), additional protection (e.g., fuses or soft-start circuits) may be needed.

5. **Dependence on Rockwell Automation Software**

Users must have **Studio 5000 or RSLogix** for programming and configuration. This can be a drawback for companies not already invested in Rockwell s ecosystem, as training and licensing costs may apply.

6. **Potential for Higher Maintenance Costs**

Rockwell Automation parts, while reliable, can be **more expensive to replace** than generic or aftermarket components. Additionally, specialized hazardous-area-certified spares may have longer lead times.

7. **No Built-In Regenerative Braking**

The 1797-1J2 does **not support regenerative braking**, meaning energy from decelerating loads is dissipated as heat. For applications requiring energy recovery (e.g., hoists or high-inertia loads), an external brake resistor or a different inverter would be required.

8. **Limited Environmental Ratings**

While certified for hazardous areas, the module may have **restrictions on temperature, humidity, or altitude** depending on the specific certification. Always verify the **ATEX/IECEX documentation** for operating conditions.

9. **No Integrated Enclosure Mounting**

The module is designed for **panel or junction box mounting** but does not include an enclosure. Users must purchase a **hazardous-area-rated enclosure** separately, adding to the installation cost.

10. **Potential for Obsolescence**

Rockwell Automation occasionally phases out older product lines. While the 1797 series is still supported, future availability may be uncertain, which could impact long-term maintenance and spare parts.

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### **Conclusion**

The **Allen-Bradley 1797-1J2 Flex Ex Frequency Module** is a **highly specialized, explosion-proof inverter** best suited for **low-power (3A), low-voltage (30V) applications in hazardous environments**. Its strengths lie in **certification, integration with Rockwell systems, and compact design**, making it ideal for industries like oil and gas, chemical processing, or mining where safety and compliance are critical.

However, its **3A current limit, 30V output restriction, and higher cost** make it **impractical for most standard industrial motor applications**. If your application requires **higher current, three-phase motors, or regenerative braking**, this module is not the right choice. Additionally, if the environment is **non-hazardous**, a standard non-certified inverter would be more cost-effective.

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### **Recommendation**

1. **Use the 1797-1J2 if:**

- You need a **hazardous-area-certified (ATEX/IECEX) inverter**.

- Your load requires ** 3A and 30V** (e.g., small actuators, gas compressors, or valve drivers).

- You are already using **Rockwell Automation controllers** (ControlLogix, CompactLogix) and want seamless integration.

- The application benefits from **digital communication (DeviceNet, EtherNet/IP)** for remote monitoring.

2. **Avoid the 1797-1J2 if:**

- Your motor requires **>3A or >30V** (consider **1797-2J2 for 6A or 1797-3J2 for 10A**).

- The environment is **non-hazardous** (standard inverters like **Danfoss VLT, Siemens Micromaster, or ABB ACS880** are cheaper).

- You need **three-phase motor control** (this module is **single-phase only**).

- Your budget is tight, as the **certification and Rockwell branding add significant cost**.

3. **Alternatives to Consider:**

- **For higher current in hazardous areas:** **Allen-Bradley 1797-2J2 (6A) or 1797-3J2 (10A)**.

- **For non-hazardous, high-power applications:** **Danfoss VLT A2000, Siemens Micromaster 440, or ABB ACS880**.

- **For three-phase control:** **Allen-Bradley PowerFlex 755T (if hazardous area is not required)**.

- **For regenerative braking needs:** **Allen-Bradley PowerFlex 755T or Siemens Sinamics G120**.

4. **Cost-Saving Tips:**

- If possible, **reuse existing hazardous-area enclosures** to reduce installation costs.

- Check for **used/refurbished units** from Rockwell or authorized distribut

Details:

Our in house technicians refurbish a wide range of high failure, obsolete parts such as: AC/DC Servo Drives, Amplifiers, Touch Screens/ HMI's, Power Supplies, PLC's, Sensors, and virtually any industrial Circuit Boards. ALLEN-BRADLEY 1797-1J2 SENSOR INPUT MODULE. We repair all types of industrial automation including AC Servo Drives, Motors, Operator Interface Panels, PLC's, Sensors, Process Controls and Timers. We endeavor to take good clear photos of our equipment that may show signs normal use such as scuffs, scratches, or other blemishes.

part #: 17971j2 prices

  • $590.54-$1623.64

specifications sensoindustria:

  • brand: Allen-bradley
  • mpn: 1797-1j2
  • type: Plc Output Module
  • analog/digital: Analog
  • controller platform: Compactlogix

returns sensoindustria:

  • paid by: Seller
  • method: Money back
  • time: 30 Days
  • policy: Returns Accepted

shipping sensoindustria:

  • transit: 2-4 Days
  • service: UPS Ground, USPS Priority Mail, UPS 2nd Day Air, UPS Next Day Air
  • carrier: UPS, USPS
  • cost: $9.42
  • type: Calculated
  • class: Standard, Expedited, One-day

seller sensoindustria:

  • city: Duncan, South Carolina
  • rating: 100.0%
  • # reviews: 7483

offer sensoindustria:

  • sold: 0
  • started: June 1, 2026
  • quantity: 1
  • availability: In Stock
  • options: Ship-to-home
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general sensoindustria:

  • condition: Used
  • PLCs HMIs > PLC Peripheral Modules > PLC Input Output Modules
type: plc output module, analog/digital: analog, controller platform: compactlogix,
category: business & industrial > plcs hmis > plc peripheral modules > plc input output modules, sku: 22940115746069751,
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2 offers $590.54–$1623.64 USD
  • Used. Offer #1 priced at $1623.64 + $9.42 shipping estimate = $1633.06* total. ALLEN-BRADLEY SENSOR INPUT MODULE.+$9.42 shipping
  • Gebraucht. Offer #2 priced at $590.54 + $0.00 shipping estimate = $590.54* total. 3A 30VDC. ALLEN-BRADLEY 2706-E23J16B1.FREE SHIPPING

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