Allen-Bradley 1768-L45 CompactLogix Processor

The Allen-Bradley 1768-L45, also cataloged as the 1768-L45 Processor, operates as a dedicated hardware component for programmable logic execution and I/O orchestration within CompactLogix control systems.

Hardware Specifications

EtherNet/IP Deterministic Networks and I/O Density Scaling

• I/O Density Scaling: Direct backplane bus support handles up to 4 local high-speed 1768 I/O modules directly attached to the CPU bank, with system expansion capability supporting up to 30 local and remote 1769 I/O modules across 3 I/O banks.
• EtherNet/IP Deterministic Networks: Interfaces with 1768 communication modules to route high-speed ControlNet and EtherNet/IP scheduled control data packets between local I/O banks and remote drop racks.
• Firmware Flash Compatibility: Firmware revision updates and system execution routines are managed directly through Studio 5000 / RSLogix 5000 software over backplane or communication port interfaces.

Frequently Asked Questions

Q: What is the maximum local module expansion capability directly attached to the 1768-L45 processor?

A: The 1768-L45 processor supports up to 4 local 1768 series I/O modules directly on the 1768 CPU bus bank, in addition to supporting up to 30 total 1769 series I/O modules across 3 banks.

Q: What are the backplane power supply requirements for the 1768-L45 CPU?

A: The unit requires 2 A at 24 VDC from the backplane power supply, resulting in total module power consumption of 48 W and a thermal power dissipation rating of 8.3 W.

Q: What mounting hardware and torque specifications are required for installation?

A: Panel mounting requires #8 or M4 machine screws tightened to a torque specification of 1.16 Nm.

Field Installation Guidelines

• Panel Mounting: Secure the processor to a grounded metal enclosure backplate using #8 or M4 screws torqued precisely to 1.16 Nm to maintain physical stability under vibration.
• Bus Expansion and Expansion Cables: When expanding across multiple I/O banks, ensure 1769 expansion cables are seated firmly and bank power supplies are sized to cover total backplane current requirements.
• Shield Grounding and Wiring: Wire communication ports using Category 2 rated shielded cables. Fasten cable shields to the cabinet ground bus to minimize common-mode noise coupling.
• Thermal Clearance: Maintain minimum top, bottom, and side enclosure clearances to facilitate natural convection cooling and limit operating ambient temperature to under 60 deg C.