1756-OB16IEF | Allen-Bradley ControlLogix 16-Point Isolated 24VDC Fast Output Module with PWM

The 1756-OB16IEF is a fast, isolated digital DC output module used for precise peer-to-peer motor and actuator control in real-time systems. It supports advanced functions like Pulse Width Modulation (PWM), configurable fault modes, and precise timing through CIP Sync, making it ideal for high-speed applications such as packaging, robotics, or motion equipment. Each of its 16 outputs is individually isolated and electronically fused, providing enhanced safety and diagnostic features. The module can echo its output data and report faults per channel. Its responsiveness under 25 µs allows it to react quickly to control commands. Overall, it enables accurate, deterministic control in industrial automation.

The 1756-OB16IEF is designed to work specifically with two Removable Terminal Blocks (RTBs): the 1756-TBCH and 1756-TBS6H. These RTBs provide secure and efficient wiring interfaces for connecting the module's outputs to field devices. The 36-pin RTBs also support keyed alignment, helping prevent incorrect module installation. Choosing the correct RTB ensures proper contact and reliability, and it's essential for system certification. Wiring should follow recommended torque and wire gauge guidelines in Rockwell’s manuals. The RTBs are not included by default and must be ordered separately based on project needs.

Yes, the 1756-OB16IEF supports Pulse Width Modulation (PWM) for every output channel, making it well-suited for analog-like control of digital loads. It allows PWM cycle times from 1 ms up to 1 hour, and on-times between 200 µs and 1 hour, giving high flexibility in motor or actuator control. The on-time accuracy is within ±20 µs, which ensures precise timing in demanding applications. This is ideal for controlling devices like proportional valves, fans, or lights. PWM configuration is done through the Studio 5000 environment, and parameters can be tuned per point. This greatly extends the module’s versatility.

Yes, the 1756-OB16IEF provides advanced diagnostics per output point, including status indication, fault detection, and output echo verification. It can detect open load, short circuit, and thermal overload conditions. Fault modes can be configured to Hold, Last State, On, or Off, and timing of transition after a fault is user-selectable (e.g., 1, 2, 5, 10 seconds, or forever). This helps with troubleshooting during development and provides runtime error reporting for operators. The module also supports a diagnostic latch to preserve fault history. These diagnostics improve uptime, reduce maintenance, and enhance operational transparency.

Yes, as of 2025, the Allen-Bradley 1756-OB16IEF remains an active product and is part of the Rockwell Automation ControlLogix platform. It continues to be supported for new installations and is recommended for applications requiring high-speed output and advanced timing features. Since it offers CIP Sync compatibility and output data echo, it's especially useful in time-critical environments. Being part of the ControlLogix family ensures long-term availability and integration with Studio 5000. However, Rockwell occasionally updates product lines, so it is wise to check with authorized distributors for lifecycle status. Currently, it is not listed as obsolete.