Product Overview

The Giddings & Lewis 502-03512-03R0​ is a Control Support Module (CSM), a foundational component for the PIC 900 series of programmable logic controllers (PLCs). This module served as a critical central interface and support board within the PIC 900 system chassis, providing the essential “backbone” functionality that connected the processor module, memory, and I/O subsystems. The 502-03512-03R0 CSM​ was responsible for managing the system bus, facilitating communication between the CPU and other installed modules, and providing necessary system-level control and timing signals. In the modular architecture of the PIC 900, the CSM was not the processor itself but the vital support infrastructure that enabled the processor to function, akin to a motherboard in a personal computer. Its proper operation was a prerequisite for the entire control system to boot, execute logic, and communicate with the outside world.This module is a key part of the legacy Giddings & Lewis (G&L) automation portfolio, which was later acquired by Siemens and subsequently integrated into other industrial lines. The value of the Giddings & Lewis PIC 900 502-03512-03R0​ module today lies primarily in the maintenance and support of existing, installed control systems. For manufacturers operating critical machinery that still relies on the robust and reliable PIC 900 platform, this module is an essential spare part for repair and lifecycle extension. Replacing a faulty 502-03512-03R0​ can restore functionality to an entire control rack, preventing costly production downtime. Its role underscores the importance of maintaining a supply of legacy components to support the long operational life of industrial automation systems, often measured in decades rather than years.

Technical Specifications

Main Features and Advantages

The Giddings & Lewis 502-03512-03R0​ provided the core system integration for the PIC 900 platform. Its primary feature was the management of the proprietary high-speed parallel system bus. This bus was the data highway connecting the central processing unit (CPU) module to all other resources in the rack, including memory expansion modules, discrete and analog I/O modules, and special function modules. The CSM handled bus arbitration, timing, and data transfer protocols, ensuring reliable and deterministic communication—a critical requirement for real-time control. It also generated essential system clocks and control signals that synchronized operations across the rack.A significant advantage of the modular design exemplified by the 502-03512-03R0​ was serviceability. In the event of a system failure, diagnostics could often isolate the problem to a specific module. The CSM, as a central component, was a common point of failure. Its modular nature allowed technicians to replace just the Giddings & Lewis Control Support Module 502-03512-03R0​ rather than the entire controller, drastically reducing repair time and cost. The board was designed for industrial durability, with robust traces and components rated for the temperature and electrical noise of a machine tool or factory environment. For users of the PIC 900 system, the availability of a genuine, tested 502-03512-03R0​ module meant the ability to extend the life of their capital equipment reliably, leveraging their existing program library and trained personnel without the need for a costly and disruptive complete control system migration.