Product Overview

The Allen-Bradley 1746-OBP16 is a high-current sourcing DC output module within the SLC 500 programmable controller family. Designed to drive demanding industrial loads that require substantial current capacity, the Allen-Bradley 1746-OBP16 provides sixteen individually controllable 24V DC output channels, each capable of handling continuous currents up to 1.5A at 30°C. This module occupies a single slot in any SLC 500 chassis—whether fixed or modular—and draws 250mA from the backplane 5V DC supply to power its internal logic and diagnostic circuitry.

What distinguishes the Allen-Bradley 1746-OBP16 from standard SLC 500 output modules is its combination of high per-point current capacity, integrated short-circuit protection, and fast turn-off characteristics for inductive loads. The module features an on-board fuse with a blown-fuse LED indicator, providing immediate visual diagnostics when a channel experiences a short-circuit condition. This design eliminates the need for external fusing on individual channels for short-circuit protection, though external overload fuses may still be required for comprehensive protection depending on load characteristics.

 

Technical Specifications

Parameter Name	Parameter Value
Product Model	Allen-Bradley 1746-OBP16
Manufacturer	Allen-Bradley (Rockwell Automation)
Product Type	High-Current DC Output Module
Voltage Category	24V DC Sourcing
Operating Voltage	20.4 to 26.4V DC
Number of Outputs	16
Points per Common	16
Continuous Current per Point	1.5A at 30°C, 1.0A at 60°C
Continuous Current per Module	6.4A
Backplane Current (5V DC)	250 mA
Signal Delay (Resistive Load)	On: 1.0 ms max, Off: 2.0 ms max
Off-State Leakage (max)	1 mA
Surge Current per Point	4A for 10 ms
Surge Current per Module	32A for 10 ms
Fuse Type	10A, Littelfuse #322010 or #332010
Fuse Kit Part Number	1746-F8
Isolation	500V DC backplane isolation
Terminal Style	Removable Screw Terminal Block
Operating Temperature	0°C to +60°C

 

Main Features and Advantages

High-Current Drive Capability: The Allen-Bradley 1746-OBP16 delivers exceptional per-point current handling with 1.5A at 30°C, enabling direct drive of loads that would typically require interposing relays or contactors with standard output modules. This capacity makes the Allen-Bradley 1746-OBP16 particularly valuable for applications involving solenoid valves, motor brakes, high-power indicator lamps, and other current-intensive field devices, reducing system complexity and component count.

Integrated Fuse Protection with Diagnostics: Each Allen-Bradley 1746-OBP16 incorporates an on-board fuse that provides short-circuit protection for the output channels. When a short circuit occurs, the blown-fuse LED illuminates to alert maintenance personnel, and the associated channel is isolated to prevent damage to other outputs. The fuse is replaceable using the 1746-F8 fuse kit, which contains five replacement fuses compatible with Littelfuse #322010 or #332010 10A ratings.

Fast Turn-Off for Inductive Loads: The Allen-Bradley 1746-OBP16 is engineered with internal surge suppressors that dramatically reduce turn-off delays when switching inductive loads such as relay coils and contactors. Comparative data shows that while a standard 1746-OB8 module exhibits a 152 ms OFF delay when switching a Bulletin 100-B110 contactor, the Allen-Bradley 1746-OBP16 achieves a 47 ms OFF delay under identical conditions. This faster response improves control precision and reduces wear on mechanical contacts.