Configured for coordinated standard and safety control execution in a ControlLogix chassis, the Allen-Bradley 1756-L72S (1756L72S GuardLogix Logix5572S Processor) executes controller logic while maintaining separate standard and safety memory resources.

Model Identification

The supplied model references identify the same processor family:

• Primary model: 1756-L72S
• Catalog reference: 1756L72S
• Spare model: 1756-L72S/B
• Controller type: GuardLogix Logix5572S Processor
• Platform: ControlLogix
• Standard memory: 4 MB
• Safety memory: 2 MB
• USB interface: 1 x USB port
• Energy storage: Energy storage module specified

Hardware Specifications

ControlLogix Backplane and Safety Architecture

The 1756-L72S combines standard controller memory with a dedicated safety memory allocation. The supplied data specifies 4 MB of standard memory and 2 MB of safety memory.

The processor draws 800 mA at 5.1 VDC and 5 mA at 1.2 VDC. These values must be included when calculating the ControlLogix chassis power load.

The stated 30 V continuous isolation voltage defines the supplied isolation specification. No additional channel-to-channel isolation value is provided in the supplied data.

Ordering Information

• 1 x Allen-Bradley 1756-L72S GuardLogix Logix5572S Processor
• 1 x Energy storage module, where included with the supplied processor configuration
• Additional ControlLogix chassis, power supply, communication modules, or terminal accessories are not specified as part of the processor data supplied.

Installation and Wiring Notes

Chassis Installation

• Install the processor in the designated ControlLogix chassis position according to the chassis hardware documentation.
• Verify the chassis power budget against the processor current draw before energizing the rack.
• Secure the module mechanically before connecting the backplane.
• Maintain adequate clearance around the chassis for heat dissipation.

Electrical Installation

• Verify the 5.1 VDC backplane load when calculating total chassis current.
• Route communication and signal wiring separately from high-current power conductors where practical.
• Use appropriate shield termination practices for connected field wiring.
• Do not apply field voltage directly to processor interfaces unless the connected interface is specifically rated for that voltage.

Safety Configuration

• Treat the standard and safety memory areas as separate controller resources.
• Verify the controller project and safety configuration before transferring logic to the processor.
• Firmware and project compatibility should be confirmed before performing controller replacement or updates.

Frequently Asked Questions

• What type of processor is the 1756-L72S?

  The 1756-L72S is identified as a GuardLogix Logix5572S Processor for the ControlLogix platform, with separate standard and safety memory allocations.

• How much standard memory is specified?

  The supplied product data specifies 4 MB of standard memory for the 1756-L72S processor.

• How much safety memory is available?

  The supplied specification identifies 2 MB of safety memory. This memory is separate from the stated 4 MB standard memory.

• What is the 5.1 VDC current draw?

  The processor has a specified current draw of 800 mA at 5.1 VDC. This value should be included in the chassis power-load calculation.

• What is the 1.2 VDC current draw?

  The supplied data specifies a current draw of 5 mA at 1.2 VDC. No additional 1.2 VDC power specification is provided.

• What isolation voltage is specified?

  The processor is specified with an isolation voltage of 30 V continuous. No additional isolation parameters are stated in the supplied product information.

• Does the processor have a USB interface?

  Yes. The supplied product information identifies 1 x USB port on the 1756-L72S processor.

• What thermal dissipation must be considered?

  The stated power dissipation is 2.5 W, with thermal dissipation listed as 8.5 BTU per hour. Chassis ventilation should account for this heat load.