Siemens 6ES5921-3WB11 CPU Module

The 6ES5921-3WB11 serves as the central processing unit for SIMATIC S5-115U PLC systems. This CPU executes user programs and manages all I/O operations. You can rely on it for medium-scale automation tasks in factory environments.

Key Technical Parameters

The table below lists all essential technical specifications for this CPU module.

Specification	Details
Part Number	6ES5921-3WB11
Product Type	CPU Module
Compatibility	SIMATIC S5-115U series
Program Memory	32 KB RAM (expandable)
Memory Backup	Lithium battery (integrated)
Processing Speed	1.5 ms per 1K binary operations
Digital I/O Capacity	1024 points
Analog I/O Capacity	64 channels
Dimensions (W x H x D)	250 mm x 25 mm x 210 mm
Weight	Approx. 0.80 kg
Interface	S5 backplane bus
Power Supply	5V DC from backplane
Operating Temperature	0°C to 60°C

Physical Characteristics and Installation

This CPU module weighs approximately 0.80 kg and occupies one single-width slot. Its dimensions measure 250 mm x 25 mm x 210 mm for standard rack mounting. First, insert the 6ES5921-3WB11 into the leftmost slot of your S5-115U rack. Then, connect the external programming device to the front interface. Finally, apply power to the backplane for normal operation.

Memory Architecture and Backup

The 6ES5921-3WB11 includes 32 KB of internal RAM for user program storage. An integrated lithium battery maintains this memory during power-down periods. Consequently, your program remains safe for extended equipment shutdowns. You can expand the memory capacity using plug-in modules. This flexibility allows scaling for larger automation projects.

Processing Capabilities and I/O Limits

This CPU executes binary operations in just 1.5 ms per thousand instructions. Therefore, it suits time-sensitive control loops and fast machine sequences. The module supports up to 1024 digital I/O points for discrete control. Additionally, it handles 64 analog channels for process monitoring. The 6ES5921-3WB11 communicates seamlessly with all S5 I/O modules.