1746-OB16 | Allen-Bradley SLC 500 Digital 24V DC Output Module 16-Channel

Technical Overview

The 1746-OB16 (Cat No. 1746-OB16) is a high-density digital output module designed for the Allen-Bradley SLC 500 fixed or modular hardware style. This module features 16 sourcing outputs, providing a reliable interface between the PLC backplane and field devices such as solenoids, motor starters, and indicators. Engineered for high-speed switching, it offers a rapid signal transition time, making it suitable for time-critical control applications. The 1746-OB16 (1746-OB16) utilizes the SLC backplane for both communication and logic-side power, ensuring seamless integration within the Rockwell Automation ecosystem.

Detailed Specifications

• Manufacturer: Allen-Bradley / Rockwell Automation

• Product Family: SLC 500 Series

• Module Type: Digital DC Source Output

• Model Number: 1746-OB16 (1746-OB16)

• Number of Outputs: 16 Points

• Nominal Operating Voltage: 24V DC

• Operating Voltage Range: 10V to 30V DC

• Backplane Current Draw (5.1V DC): 0.280 A (280mA)

• Continuous Current per Point: 0.5A @ 30 °C (86 °F); 0.25A @ 60 °C (140 °F)

• Maximum Current per Module: 8.0A @ 30 °C; 4.0A @ 60 °C

• Surge Current per Point: 1.0A for 10ms (repeatable every 2 seconds)

• Signal Delay (Off to On): Max 0.1 ms

• Signal Delay (On to Off): Max 1.0 ms

• Off-State Leakage Current: Maximum 1.0 mA

• On-State Voltage Drop: Maximum 1.2V at 0.5A

• Thermal Dissipation: 7.6 Watts (Total)

• Isolation: 1500V AC (between backplane and I/O)

Module Comparison and Selection

When selecting between the 1746-OB16 (1746-OB16) and other SLC modules, it is important to note that the OB16 is a sourcing module (sends current to the load). If your field devices require a sinking configuration (drawing current from the load), the 1746-OV16 would be the appropriate alternative. For applications requiring higher current capacity per point, the 1746-OBP16 provides similar density with enhanced power handling.

Common Questions for Engineers

Does this module require an external power supply?Yes. While the logic side is powered by the SLC backplane, the field-side outputs require a 10-30V DC external power source connected to the module terminals to drive the connected loads.

Is the module protected against short circuits?The 1746-OB16 (1746-OB16) does not include internal electronic short-circuit protection. It is highly recommended to use external fuses (such as 1746-F1 or equivalent) to protect the circuitry from overcurrent conditions.