Siemens SIMATIC 545/555-1105 / 1106 PLC CPU Module (For Parts / Not Working)

Product Overview

The Siemens SIMATIC 545/555-1105 and 555-1106 are industrial PLC CPU modules belonging to the classic SIMATIC Series 505 automation system. These controllers were widely used in factory automation, process control, and industrial machinery applications.

This listing is for units in “for parts or not working” condition, typically intended for repair, refurbishment, or spare parts recovery in legacy automation systems.

The SIMATIC 505 platform is part of Siemens’ long-established industrial PLC family designed for reliable control of machines and processes.

Industrial PLC System Background

The SIMATIC 505 series is an early generation programmable logic controller system developed for industrial automation tasks such as machine sequencing, process monitoring, and distributed I/O control.

These systems use modular CPU and I/O architecture, allowing flexible configuration depending on application requirements.

They are commonly found in older industrial plants that still rely on stable legacy control systems.

CPU Module Function

The 545 and 555 CPU modules act as the central processing unit of the PLC system, executing control logic programs and managing I/O communication.

They process input signals from sensors and send output commands to actuators and industrial equipment.

The 555-1105/1106 variants support enhanced processing capabilities and communication options compared to earlier models.

PROFIBUS Communication Capability

These PLC CPUs support industrial communication protocols such as PROFIBUS DP for integration with distributed I/O systems.

This allows connection to remote I/O stations and field devices in large-scale automation networks.

The system enables centralized control across multiple industrial process areas.

System Architecture

The SIMATIC 505 system consists of CPU modules, power supplies, and expandable I/O racks.

It supports both local and remote I/O configurations depending on system design.

This modular structure makes it suitable for complex industrial automation applications.

Typical Industrial Applications

These PLC systems were widely used in manufacturing plants, energy systems, water treatment facilities, and process industries.

They are suitable for machine control, sequencing operations, and industrial monitoring systems.

Even today, they remain in service in legacy industrial environments.

Condition: For Parts / Not Working

This unit is sold as “for parts or not working”, meaning it may not function correctly and is intended for technical users, repair specialists, or spare parts sourcing.

It can be used for component-level repair, system maintenance, or replacement part recovery in existing installations.

No guarantee of full operational performance is implied in this condition.

Engineering Value

From an engineering perspective, SIMATIC 505 systems are known for their robust industrial design and long-term reliability in harsh environments.

Many industrial facilities still maintain these systems due to their stable operation and established infrastructure.

Replacement and spare parts remain important for extending system life.

Conclusion

The Siemens SIMATIC 545/555-1105 and 555-1106 PLC CPU modules are legacy industrial automation controllers from the Series 505 system. This listing, offered as for parts or not working, is suitable for repair, refurbishment, or spare parts use in industrial environments.

Their historical importance and continued industrial usage make them valuable components in legacy automation maintenance.