The Allen-Bradley 1746-OB32E Output Module is a high-density digital output solution designed for the SLC 500 system, providing reliable performance for industrial automation tasks. In this in-depth blog, we’ll explore its detailed specifications, explain what each feature means in practice, and highlight its applications across industries. By the end, you’ll understand why this output module is a cornerstone for many legacy and modern automation systems.
Introduction to the Allen-Bradley 1746-OB32E Output Module
The Allen-Bradley 1746-OB32E Output Module is part of the renowned SLC 500 modular hardware style, a programmable logic controller (PLC) system that has supported industrial processes for decades. This module offers 32 digital output channels, making it ideal for applications requiring multiple discrete control signals without taking up excessive rack space.
For engineers, maintenance professionals, and system integrators, this module delivers durability, flexibility, and compactness. Its specifications make it suitable for a variety of control scenarios, from factory automation to process industries.
Allen-Bradley 1746-OB32E Specifications
32 Digital Output Channels
The module supports 32 discrete digital outputs, allowing control of multiple devices such as relays, solenoids, and indicator lamps. Each output provides sourcing functionality, meaning the module supplies current to the connected load.
Voltage Range: 5–50 VDC (Nominal 24 VDC)
The Allen-Bradley 1746-OB32E Output Module is rated for a wide voltage range of 5 to 50 VDC, with 24 VDC being the nominal and most commonly used voltage in industrial systems. This flexibility ensures compatibility with a variety of industrial devices.
Current Ratings
● Per Channel: 0.25 A at 60 °C
● Total Module Current: 8 A across all outputs
● Surge Current: Up to 1 A for 1 ms every 2 seconds
These current ratings ensure the module can handle typical industrial loads while also managing short-duration inrush currents common in inductive devices.
Backplane Current
The module draws approximately 190 mA at 5 V from the backplane. This value is essential for system designers to consider when calculating overall power consumption in the SLC chassis.
Switching Speed
● Turn-On Delay: 0.1 ms
● Turn-Off Delay: 1.0 ms
Fast switching times make the Allen-Bradley 1746-OB32E Output Module suitable for high-speed applications such as packaging and material handling.
Isolation
The module provides 1500 V AC isolation for 1 minute between output circuits and internal logic, protecting sensitive control systems from surges and electrical noise.
Environmental Ratings
● Operating Temperature: 0–60 °C (32–140 °F)
● Humidity: 5–95% non-condensing
● Shock: 30 G
● Vibration: 2.5 G at 10–200 Hz
These specifications confirm the module’s ability to withstand harsh industrial environments.
LED Indicators
Each channel features an LED indicator, providing quick visual feedback of output status. This aids troubleshooting and enhances diagnostic efficiency.
Understanding Key Specifications and Their Importance
Output Density
Having 32 outputs in a single module increases I/O density, allowing system designers to save rack space. In large systems, this reduces panel size and wiring complexity.
Voltage Flexibility
The broad 5–50 VDC range allows the module to be used across multiple applications. While 24 VDC is standard, the ability to handle higher or lower voltages makes it adaptable to legacy systems and diverse industrial environments.
Current Ratings and Load Considerations
The 0.25 A per channel rating is adequate for driving indicator lamps, relays, and small solenoids directly. For higher-current devices, external relays can be used. The 8 A total module current limit ensures overall thermal management, preventing overheating.
Backplane Power Consumption
At 190 mA, the module’s backplane consumption is moderate but must be accounted for in multi-module racks. Proper planning avoids overloading the chassis power supply.
Fast Switching
The ability to switch outputs quickly (0.1 ms ON, 1.0 ms OFF) ensures responsiveness in applications where timing precision is critical, such as conveyor belt sorting or automated packaging lines.
Isolation
The 1500 V AC isolation rating safeguards the PLC logic from external surges, protecting the system’s integrity and extending lifespan.
Diagnostics
The per-channel LED indicators are vital for field technicians, reducing downtime by simplifying troubleshooting.
Applications of the Allen-Bradley 1746-OB32E Output Module
Manufacturing Automation
In production lines, the module controls solenoids, pilot lamps, and relays that manage machinery operation. Its high output density makes it a cost-effective solution for plants with multiple discrete control points.
Material Handling Systems
The Allen-Bradley 1746-OB32E Output Module drives conveyor diverters, pushers, and sorting actuators, where precise timing and reliability are critical.
Packaging Machinery
Fast response times enable accurate control of packaging equipment, ensuring smooth operations in industries such as food, beverage, and pharmaceuticals.
Process Industries
In water treatment plants, chemical facilities, and oil & gas operations, the module controls valves, alarms, and pumps. Its wide voltage tolerance makes it compatible with diverse field devices.
Building Automation
From lighting systems to HVAC control, the module provides discrete switching needed in large facilities, demonstrating its versatility beyond heavy industry.
Legacy System Support
The SLC 500 series remains widely deployed in legacy systems. The Allen-Bradley 1746-OB32E Output Module continues to provide reliable replacements for maintaining and extending the life of existing automation infrastructures.
Why Choose the Allen-Bradley 1746-OB32E Output Module?
● High Density: 32 outputs reduce rack space requirements.
● Wide Voltage Range: Compatible with various devices and systems.
● Reliability: Proven performance in harsh industrial conditions.
● Fast Switching: Supports time-sensitive applications.
● Diagnostic LEDs: Simplify troubleshooting.
● Compatibility: Seamless integration into existing SLC 500 racks.
Conclusion
The Allen-Bradley 1746-OB32E Output Module offers a balance of density, performance, and reliability for industrial automation. With 32 sourcing digital outputs, wide voltage compatibility, and rugged environmental ratings, it remains a trusted choice in both legacy and ongoing projects. Whether used in manufacturing, process industries, or material handling, this module provides dependable control for critical applications.
If you are considering upgrading or maintaining your SLC 500 system, the Allen-Bradley 1746-OB32E Output Module is an essential component worth evaluating. Explore more about this product and related solutions on our product page.
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Pro tip: When driving inductive loads such as solenoids, always consider surge suppression to protect both the module and connected devices from damaging transients.
