Allen-Bradley 1747-L553/B SLC 5/05 Processor Module

The Allen-Bradley 1747-L553/B, also cataloged as the 1747-L553 CPU processor module, serves as the primary SLC 5/05 execution unit for scan-based instruction processing across SLC 500 backplane architectures with integrated Ethernet communication capability.

Configured for deterministic ladder logic execution and TCP/IP messaging within SLC 500 chassis systems, the Allen-Bradley 1747-L553/B (1747-L553 CPU processor module) provides direct backplane arbitration-based processing with RS-232 and Ethernet physical layer interfaces.

Suffix Breakdown & Model Matrix

The suffix “/B” indicates a hardware revision level within the 1747-L553 product line. No additional functional segmentation or option coding is defined in the provided dataset.

Hardware Specifications

EtherNet/IP Backplane Arbitration & I/O Density Scaling Behavior

The SLC 5/05 architecture executes program instructions through cyclic backplane arbitration, where CPU scan sequencing is synchronized with chassis-level I/O refresh windows. Ethernet communication operates over TCP/IP with scan-tied scheduling, resulting in throughput dependency on instruction density and I/O polling load. Memory allocation is partitioned into program, data table, and communication buffers within a fixed 64 K words architecture. I/O expansion across multiple chassis introduces backplane load distribution constraints governed by scan cycle timing and bus arbitration latency.

Frequently Asked Questions (FAQ)

Q: Can the 1747-L553/B CPU module be hot-swapped under energized conditions?
A: No. The SLC 500 backplane architecture does not support live insertion or removal of CPU modules during operation.

Q: Does Ethernet communication operate independently from scan execution timing?
A: No. TCP/IP communication is processed within the CPU scan cycle and is subject to scan load and instruction execution time.

Q: Are different “/B” revisions electrically interchangeable?
A: They may be mechanically compatible within the same chassis, but firmware and revision alignment must be verified prior to replacement.

Field Installation Guidelines

The module shall be installed only after full removal of chassis power. The CPU must be fully engaged into the SLC 500 backplane connector to ensure stable bus communication integrity. Ethernet cabling shall be separated from high-noise conductors such as motor drives and relay coils to minimize electromagnetic coupling. Shield termination shall be grounded at a single reference point to avoid ground loop formation. RS-232 programming interface should be used with short, shielded cables under commissioning conditions.