Siemens 6ES5921-3KA12 Processor Module

The 6ES5921-3KA12 serves as a processor module for SIMATIC S5 automation systems. This unit executes user programs and manages all I/O operations. Its rectangular frame measures 232 millimeters in width. The module height reaches 210 millimeters exactly. Depth stays at 155 millimeters. You will find this unit weighs approximately 1.22 kilograms. Therefore, installation requires sliding the module into a standard S5 rack slot. One front-panel serial port connects to programming software.

Physical Layout and Connectors

The front panel features a 4-line LCD display for system diagnostics. You will find eight push buttons for local configuration access. One RS-232 port supports connection to a programming terminal. Three status LEDs indicate run, stop, and fault conditions. Two guide rails secure the module firmly in the rack.

Technical Specifications

Parameter	Specification
Module Width	232 mm
Module Height	210 mm
Module Depth	155 mm
Unit Weight	1.22 kg
Processor	16-bit @ 10 MHz
Program Memory	48 KB (EPROM)
Data Memory	24 KB (retentive)
Scan Time	1.8 ms per 1K instructions
Digital I/O Capacity	1024 max
Communication Port	RS-232 (programming)
Component Total	742 discrete parts
Internal Energy Storage	1500 µF capacitor bank
Backup Battery	Lithium (3.6V, 5 years)
Operating Temperature	0°C to +55°C

Internal Design and Energy Storage

The 6ES5921-3KA12 contains exactly 742 discrete components inside. A 1500 microfarad capacitor bank filters the main power supply input. This bank holds enough charge for 25 milliseconds after power loss. The 16-bit processor runs at 10 megahertz for reliable execution. A lithium battery retains data memory for up to five years. EPROM stores the user program without any battery backup required.

Operational Performance

This processor module executes logic from 48 kilobytes of program memory. It scans 1,000 instructions in approximately 1.8 milliseconds. Moreover, the unit handles up to 1024 digital I/O points system-wide. The RS-232 port allows connection to programming software. The LCD display shows real-time system status and diagnostic messages. Eight buttons let you navigate menus without a programming computer. Consequently, you achieve dependable control for medium-sized automation projects. Siemens designed this processor for SIMATIC S5 platform applications.

In summary, the 6ES5921-3KA12 delivers reliable processor module performance. Use this CPU for factory automation or process control systems. It provides stable execution for S5 automation tasks. Order this processor module for your Siemens SIMATIC S5 system.