Allen-Bradley 1768-L45S CompactLogix GuardLogix Controller

The Allen-Bradley 1768-L45S, also cataloged as the 1768-L45 GuardLogix Safety Controller, operates as a dedicated hardware component for SIL 3 / PL e safety logic execution and system orchestration within CompactLogix control systems.

Suffix Breakdown & Model Matrix

Hardware Specifications

EtherNet/IP Deterministic Networks and Firmware Flash Compatibility

• I/O Density Scaling: Direct backplane bus support handles up to 4 local high-speed 1768 modules attached to the CPU bank, with system expansion supporting up to 30 local and remote 1769 Compact I/O modules distributed across 3 I/O banks.
• EtherNet/IP Deterministic Networks: Coordinates safety task execution and standard control messaging over EtherNet/IP and ControlNet deterministic networks using CIP Safety protocol extensions across adjacent 1768 communication modules.
• Firmware Flash Compatibility: Fully synchronized with Studio 5000 / RSLogix 5000 configuration environments, enforcing safety signature validation, memory partition locking, and firmware flashing routines via backplane or serial links.

Frequently Asked Questions

Q: How is internal memory partitioned on the 1768-L45S GuardLogix processor?

A: The module contains 3 MB of standard memory allocated for process routines and standard logic, alongside 1 MB of dedicated safety memory reserved exclusively for safety task routines.

Q: What are the backplane current draw and power consumption metrics for the 1768-L45S?

A: The controller draws 2.1 A at 24 VDC from the backplane, resulting in a maximum power consumption rating of 50.4 W and a thermal power dissipation of 9.5 W.

Q: What physical communication ports are directly integrated into the processor front panel?

A: The unit includes one embedded RS-232 serial interface port for direct point-to-point programming, ASCII device connection, or modem interface.

Field Installation Guidelines

• Chassis Mounting: Secure the controller directly to a grounded metal panel or DIN rail inside a protective cabinet using M4 or #8 mounting screws, ensuring locking latches are fully engaged.
• Power Isolation during Cabling: Isolate power to the controller and external serial devices before connecting or disconnecting the RS-232 serial cable to eliminate electrical arcing hazards in classified areas.
• Serial Cable Shielding: Utilize standard 1756-CP3 or 1747-CP3 serial cables with right-angle connectors, ensuring low-impedance connection of the cable shield to cabinet ground.
• Heat Dissipation Clearance: Maintain adequate top and bottom panel ventilation spacing to allow convection airflow to dissipate up to 9.5 W of operating thermal energy.