Siemens 6ES5924-3SA11 | SIMATIC S5-135U CPU 924

The Siemens 6ES5924-3SA11 powers large-scale automation tasks as a high-performance CPU. This processor belongs to the SIMATIC S5-135U family for complex control systems. You can program it using STEP 5 with statement list, ladder, or function block diagrams. It supports up to 4096 digital I/O points across multiple expansion racks. Consequently, this unit suits chemical plants, power generation, and heavy manufacturing lines.

Technical Specifications Overview

Parameter	Detailed Specification
Model	Siemens 6ES5924-3SA11
Category	SIMATIC S5-135U Central Processing Unit (CPU 924)
Processor Type	16-bit bit-slice (AMD 2900 family)
Program Memory	32 KB RAM (battery-backed, expandable to 64 KB)
Data Memory	32 KB (flags, timers, counters, data blocks)
Execution Speed	1 ms per 1K of statement list (STL)
Maximum I/O Points	4096 digital / 256 analog (with expansion racks)
Built-in Interfaces	AS511 (programming), second serial port (optional)
Operating Voltage	5V DC from backplane (typical 1.2 A)
Energy Storage	Replaceable lithium battery for RAM and clock
Battery Life	Approximately 2 years (CPU powered off)
Dimensions	250 mm x 50 mm x 130 mm (double-width)
Weight	0.98 kg (980 grams)
Indicators	5 LEDs (power, run, stop, battery, bus fault)
Operating Temperature	0°C to 60°C

Functional Features and Processing Capabilities

The Siemens 6ES5924-3SA11 executes complex math and floating-point operations efficiently. You can store up to 4000 function blocks within the 32 KB program memory. The CPU includes 2048 internal flags, 256 timers, and 256 counters. Furthermore, it supports interrupt-driven processing for high-speed event responses.

This central processing unit features a built-in real-time clock with battery backup. The clock enables time-based program execution and event logging. Additionally, the processor handles multi-computing configurations with up to four CPUs. The hardware watchdog resets the system automatically during software failures.

Installation and Configuration Steps

First, insert the Siemens 6ES5924-3SA11 into the first slot of your S5-135U rack. Next, connect a programming device to the AS511 port on the front panel. Then, verify the battery voltage using the front LED indicator. Finally, download your STEP 5 program through the serial interface.

You must replace the lithium battery every two years as preventive maintenance. The CPU loses all programs and data after complete battery discharge. Always place the CPU in STOP before removing it from the rack. Furthermore, back up your program to an EPROM memory submodule for safety.

This central processing unit works perfectly for large bottling lines and conveyor systems. It also controls steel processing and paper manufacturing machinery reliably. The Siemens 6ES5924-3SA11 supports all S5-135U communication and I/O modules. You can upgrade to a faster CPU without changing existing I/O wiring.