Siemens 6ES5921-3WB14 | CPU Unit for SIMATIC S5-115U PLC

High-Performance Processor for SIMATIC S5-115U Systems

The 6ES5921-3WB14 robust CPU unit serves as the central processing core for SIMATIC S5-115U programmable controllers. This processor module executes user programs and manages all system resources with high reliability. It utilizes the STEP 5 programming language for flexible automation solutions. Therefore, this CPU suits demanding applications requiring dependable control in harsh industrial environments.

Technical Specifications

Parameter	Specification
Manufacturer	Siemens
Product Line	SIMATIC S5
Model	6ES5921-3WB14
Product Type	CPU Unit / Processor Module
Compatibility	SIMATIC S5-115U
Programming Language	STEP 5 (STL, LAD, CSF)
Memory Capacity	32 KB (expandable)
Memory Type	CMOS RAM
Integrated I/O Capacity	16 digital inputs, 16 digital outputs
Interfaces	Programming port
Mounting	Standard S5 rack slot
Operating Temperature	0°C to 60°C
Certifications	CE, UL, CSA

Memory Architecture and Expansion Options

The 6ES5921-3WB14 features 32 KB of CMOS RAM for program and data storage. This memory is expandable via plug-in submodules. Furthermore, the CPU includes a real-time clock for time-stamping events. The module also provides integrated I/O, including 16 digital inputs and 16 digital outputs. Consequently, this design reduces the need for additional I/O modules.

Integrated I/O and System Integration

This CPU unit includes onboard 24 V DC inputs and outputs for basic control tasks. Users can connect pushbuttons, switches, and sensors directly to the input terminals. Similarly, the outputs drive relays, solenoid valves, and indicator lamps. The 6ES5921-3WB14 communicates with additional I/O modules via the backplane bus. Thus, it offers seamless expansion for larger automation systems.

Physical Characteristics and Installation

The 6ES5921-3WB14 occupies a single slot in the S5-115U chassis. Its robust construction withstands vibration and temperature variations. The front panel includes LED indicators for power, run, and fault status. Additionally, a programming port provides connection to programming devices. Users can install this module quickly without special tools.

Product Status

The 6ES5921-3WB14 forms part of the legacy SIMATIC S5 product line. Siemens has discontinued this module as a current production item. However, users may still source this unit through industrial automation distributors offering new old stock.