Allen-Bradley 1756-L63 ControlLogix Logix5563 Processor — 8 MB Memory, Series B

Application Scenarios

A regional brewery was running a packaging line built around a ControlLogix system that had been in service for more than a decade. Production had expanded twice, and the original 1756-L63​ was approaching the practical limit of its I/O and program capacity. Rather than rebuild the control architecture, the plant engineers retained the entire 1756 I/O investment and slotted a second 1756-L63​ into the same chassis alongside the original. ControlLogix supports multiple controllers in one rack, separated only by power-supply headroom and application design. The new processor took ownership of the added filler and labeller cells, while the existing program and wiring stayed untouched. Production was never stopped for a platform migration.That is the defining strength of the platform. A 1756-L63​ does not sit in isolation — it sits on a backplane with power supplies, I/O, communications, and motion modules around it. When something fails, the plant does not replace a proprietary box; it replaces one module. And because the controller can share a chassis with other CPUs, capacity can be added without abandoning the original investment.

Parameters

Technical Principles and Innovative Values

Innovation Point 1 — A Single Engine for Discrete, Process, Batch, Motion, Safety, and Drive Control.​ The 1756-L63​ runs on the Logix control engine, which lets one controller handle ladder logic, structured text, function block, and sequential function chart in the same project. A plant can therefore manage a continuous process loop, a batch recipe, an axis move, and a drive command from one set of tags rather than stitching five subsystems together.Innovation Point 2 — 8 MB of Memory in the Mid-Range Slot.​ At 8 MB, the 1756-L63​ is the larger-memory Logix5563 variant (the comparable L61 carries 2 MB). That headroom matters for applications with substantial tag tables, extensive alarms and history, add-on instructions, phase logic, or motion buffering. It is the reason the controller can support 128,000 digital I/O points and 4000 analog I/O points within a single project.Innovation Point 3 — Controller-to-Controller Messaging on the Backplane.​ Multiple 1756-L63​ CPUs can occupy one chassis and exchange data through backplane messaging. That turns a single rack into a partitioned control system: one controller owns safety-critical or high-speed logic, another owns a production cell, a third owns data handling — without adding network hardware or rewriting the I/O layer.Innovation Point 4 — 250 TCP Connections and 100 EtherNet/IP Nodes.​ The controller’s communication capacity supports a substantial integration footprint: HMIs, historians, MES, SCADA, peer controllers, drives, and I/O devices can all connect without the controller becoming the bottleneck. The single RS-232 Channel 0 remains available for local terminal work, ASCII devices, or a legacy DF1 link.Innovation Point 5 — Hot-Swappable Under the Right Conditions.​ The 1756-L63​ is designed for live insertion and removal from the chassis without powering down the rack, provided the system has been designed for it. This capability, when used with a proper redundancy configuration, can turn a CPU swap from a planned shutdown into a controlled online operation.Innovation Point 6 — Series B Hardware with a Battery Rule of Its Own.​ The Series B revision of the 1756-L63​ requires a 1756-BA2 battery, while Series A units use the 1756-BA1. The two are not interchangeable in practice — fitting a BA1 into a Series B controller will lead to rapid discharge and loss of program and retained tag data on the next power interruption. The CompactFlash card stores the program independently of the battery, which gives the plant a second line of defence.