Siemens 6ES5900-7AB11 CPU Processor Module

This module serves as the central processing unit for medium-scale automation tasks. The Siemens 6ES5900-7AB11 executes user logic and manages all I/O communication efficiently. It measures 232 mm in width and 75 mm in height. This unit weighs approximately 0.92 kg for secure rack installation.

Technical Specifications Table

Parameter	Value
Product Model	Siemens 6ES5900-7AB11
Category	CPU Processor Module
Compatible Racks	SIMATIC S5-115U
User Memory	16 KB RAM (battery-backed)
Memory Technology	Static RAM with lithium battery
Processing Speed	1.2 ms per 1K of bit operations
I/O Address Space	512 digital inputs + 512 digital outputs
Timer/Counter Range	128 timers, 128 counters
Dimensions (W x H x D)	232 mm x 75 mm x 130 mm
Weight	0.92 kg
Front Interface	1 x 20-pin female connector
Programming Port	1 x 15-pin SUB-D (TTY interface)
Internal Components	1 x 8-bit microprocessor, 1 x quartz oscillator
Energy Storage	1 x 3.6 V lithium battery (0.5 Ah capacity)
Battery Life	Approximately 1.5 years
Operating Temperature	0°C to 60°C

Internal Architecture and Processing Logic

This CPU contains a high-performance 8-bit microprocessor running at 8 MHz. A quartz oscillator provides precise timing for all logic operations. The Siemens 6ES5900-7AB11 stores user programs in 16 KB of static RAM. A replaceable 3.6 V lithium battery maintains this memory during power outages. The processor executes bit operations in approximately 1.2 milliseconds per kilobyte. Consequently, this unit handles medium-sized applications like packaging machines and conveyor systems.

Installation and Programming Guide

First, insert this CPU into the designated slot of your S5-115U rack. Next, connect your programming device to the 15-pin SUB-D TTY port. Then, upload your STEP 5 program using an appropriate programming cable. The module supports all standard STEP 5 operations including timers and counters. You can expand I/O by adding up to 2 extension racks. This CPU communicates with remote I/O via the built-in backplane interface. Always replace the lithium battery when the low voltage indicator lights up. Remove the module from the rack before changing the battery for safety.