Siemens 6ES5920-3UA12 CPU920 Central Controller

Technical Specifications and Processing Core

The Siemens 6ES5920-3UA12 central controller module, also known as the CPU920, forms the core of the SIMATIC S5-920U compact PLC system . This high-performance processor module handles all logical operations, task scheduling, and system management within the automation environment . It integrates a 16-bit processor with onboard memory and a number of local I/O interfaces . The module measures approximately 26.4 cm x 21.2 cm x 5.5 cm and weighs about 0.3 kg to 0.5 kg . It operates on a 24V DC supply and features a 256 KB memory with a maximum expansion capacity of 1.5 MB . The module’s dimensions are roughly 26.4 cm x 21.2 cm x 5.5 cm, and it weighs approximately 0.5 kg .

Parameter	Specification
Manufacturer	Siemens
Model Number	6ES5920-3UA12
Product Name	CPU920
Product Family	SIMATIC S5
Compatible System	S5-920U
Processor Type	16-bit high-performance
Memory Capacity	256 KB (max. 1.5 MB)
Integrated I/O	Digital inputs/outputs, analog interfaces
Communication Interface	MPI, PROFIBUS DP (via CP)
Power Supply	24V DC
Operating Temperature	-25°C to +60°C
Storage Temperature	-40°C to +85°C
Protection Degree	IP20
Dimensions (W x H x D)	26.4 x 21.2 x 5.5 cm
Weight	Approx. 0.5 kg
Programming Software	STEP 5
Product Status	Discontinued (Legacy)

Functional Capabilities and System Architecture

The 6ES5920-3UA12 module actively executes user-programmed logic instructions and processes all input and output signals for real-time system management . It supports complex logical operations, mathematical calculations, and data processing tasks . The module’s integrated I/O capabilities allow it to control smaller applications without additional modules, reducing system complexity and cost . Furthermore, it supports expansion through IM304/IM308 interface modules to connect multiple expansion racks (ER), scaling the system from dozens to over a thousand I/O points . The module also accommodates communication processors (CP) for networking with HMIs and other control systems .

Application Scenarios and Legacy Support

This central controller suits a variety of industrial applications, particularly where space is at a premium . It performs effectively in packaging machines, textile machinery, and small water treatment stations . Many facilities continue to rely on the Siemens CPU920 to maintain their existing S5-920U automation infrastructure . Its robust design ensures dependable operation in demanding environments . For system integrators, this module provides a practical solution for sustaining legacy automation systems.