Allen-Bradley 1756-OB8I ControlLogix Isolated DC Output Module

The Allen-Bradley 1756-OB8I is a chassis-based digital output module designed for ControlLogix automation architectures. It features eight individually isolated DC output channels operating across a 10-30 VDC voltage range. This module delivers reliable signal switching for industrial field devices requiring channel-to-channel electrical isolation and robust performance in demanding production environments.

Isolated Channel Architecture and Switching

Each of the eight output points on the module is individually isolated, preventing ground loops and protecting control circuitry from electrical noise or voltage transients originating from field devices. The module accommodates nominal 12-24 VDC circuits with a flexible operating range of 10-30 VDC.

Because the module does not feature internal electronic fusing, external fusing or a compatible fused interface module should be incorporated into the installation to safeguard against overcurrent conditions and short circuits.

System Integration and Wiring Requirements

The unit mounts directly into any standard ControlLogix chassis slot and communicates efficiently via backplane data connections. Power dissipation reaches a maximum of 4.6 W at rated operating conditions, requiring proper enclosure thermal management.

Field wiring is terminated using dedicated removable terminal blocks such as the 1756-TBCH or 1756-TBS6H housings, which must be ordered separately. Terminal blocks secure clean physical connections while allowing rapid maintenance replacement without disturbing field wiring.

Specifications

Frequently Asked Questions

Q: Are the removable terminal blocks included with the 1756-OB8I module? A: No, removable terminal blocks such as the 1756-TBCH or 1756-TBS6H must be purchased separately as system accessories.

Q: Does the 1756-OB8I module provide internal electronic fusing? A: No, this module does not include internal electronic fuses. Using external protection or a fused interface module is recommended to safeguard output circuits.