Configured for safety-critical logic processing in industrial control networks, the Allen-Bradley 1756-L73SK (1756-L73SK GuardLogix Controller) provides direct physical and electrical execution of safety instructions via a dual-processor architecture within the ControlLogix backplane environment.

Catalog Designation and Series Identification

The 1756-L73SK belongs to the ControlLogix series, specifically engineered with "K" suffix conformal coating to provide protection against harsh environmental contaminants. It functions as a safety-rated controller that manages both standard and safety-related tasks within a unified control architecture, utilizing internal memory to facilitate rapid instruction execution and deterministic I/O updates.

Hardware Technical Specifications

Deterministic Network and Control Integration

The 1756-L73SK supports integration into EtherNet/IP deterministic networks, enabling synchronized data exchange between the controller and remote I/O nodes. The firmware architecture ensures high-speed backplane bus communication, allowing for scalable I/O density management. Users must ensure that the backplane power supply capacity is sufficient to support the module's 800 mA current draw on the 5.1 VDC rail to maintain operational stability. Compatibility with flash-updateable firmware allows for the implementation of safety instruction set revisions within the Studio 5000 environment.

Ordering Information

• 1 x 1756-L73SK GuardLogix Controller module.

• 1 x 1756-BA1 battery assembly for memory retention.

• 1 x Product documentation and compliance instruction set.

Hardware Installation Guidelines

• Physical Mounting

• Insert the module into any available slot in a ControlLogix chassis, ensuring proper engagement with the backplane connectors.

• Secure the module using the top and bottom mounting screws to minimize mechanical vibration and ensure a solid chassis ground connection.

• Electrical Termination and Grounding

• Confirm that the power supply for the chassis is isolated before installing or removing the module.

• Use shielded communication cabling for EtherNet/IP connections to prevent electromagnetic interference.

• Maintain clearance around the module to allow for adequate airflow and heat dissipation as specified in the thermal profiles.

Frequently Asked Questions

• What is the primary function of the conformal coating?

  The "K" suffix indicates the module is conformal coated to protect internal circuitry from moisture, dust, and corrosive gases in harsh industrial environments.

• Can this module be hot-swapped?

  Yes, the controller supports removal and insertion under power (RIUP), allowing for maintenance without stopping the entire backplane operation, provided specific safety protocols are followed.

• Is the 8 MB user memory dedicated to safety tasks?

  The 8 MB of user memory is shared between standard control logic and safety logic; users must partition the memory according to the specific safety and functional requirements.

• How is the isolation voltage specified?

  The 30 V isolation rating refers to the continuous voltage isolation between the backplane and the internal logic circuits, protecting against transient electrical noise.

• What happens if the internal battery fails?

  The battery maintains the real-time clock and volatile memory during power loss; failure requires replacement to prevent loss of program data during unexpected power cycles.

• Does this controller support redundant configurations?

  While the 1756-L73SK is a singular unit, it is designed for integration into systems where redundant I/O configurations are managed via network protocols.

• Why is the thermal dissipation 8.5 BTU/hour?

  This represents the power converted to heat during operation. It is a low-energy profile, but requires the chassis cabinet to have active or passive ventilation.

• How is the firmware updated?

  Firmware is updated via the USB port on the front of the module or over the network using the ControlFlash utility within the programming software environment.