Siemens 6ES5102-8MA01 CPU102 Central Processor

Technical Specifications and Processing Core

The Siemens 6ES5102-8MA01 central processor, also known as the CPU 102, serves as the core processing unit for the SIMATIC S5-100U programmable logic controller system . This CPU module executes user programs and manages communication with I/O modules in small to medium-sized automation applications . The unit operates on a 24V DC power supply and features a compact design . The module provides 4 KB to 8 KB of user memory, depending on the specific firmware version . Its dimensions measure approximately 50 mm x 150 mm x 180 mm (W x H x D) .

Parameter	Specification
Manufacturer	Siemens
Model Number	6ES5102-8MA01
Product Name	CPU 102
Product Family	SIMATIC S5-100U
Processor Type	8-bit/16-bit hybrid architecture
User Memory	4 KB – 8 KB (RAM or EPROM)
Execution Speed	2.5 µs – 5.0 µs (bit instruction)
Timers / Counters	128 each
Expansion Racks	Up to 4 (via IM 102)
Maximum I/O Points	Approximately 512
Communication Interface	Integrated MPI/programming port
Supply Voltage	5V DC (backplane) / 24V DC
Current Consumption	1.2 A – 1.5 A (5V DC)
Battery Backup	Lithium battery (keeps RAM)
Operating Temperature	0°C to +55°C
Protection Rating	IP20
Dimensions (W x H x D)	50 x 150 x 180 mm
Weight	0.29 kg
Programming Software	STEP 5
Product Status	Discontinued (Legacy)

Functional Capabilities and System Architecture

The 6ES5102-8MA01 module actively executes user logic programs created with STEP 5 software . It processes binary and word instructions for real-time control tasks, though its speed is slower than modern PLCs . The CPU supports both RAM (battery-backed) and EPROM memory options for program storage . Moreover, the module supports up to 128 timers and 128 counters for sequencing and counting operations . The integrated MPI/programming port allows engineers to connect a programming device or PC for online monitoring and debugging via a dedicated adapter . The front panel LEDs provide clear visual status indication for RUN, STOP, BATF (battery fault), SF (system fault), and FRCE (force) conditions . Consequently, maintenance teams can quickly diagnose system issues without requiring additional tools.

Application Scenarios and Legacy Support

This central processor suits small to medium-sized automation applications within the S5-100U platform . It performs effectively in packaging machinery, textile equipment, printing presses, and building automation systems . The Siemens CPU 102 also serves as a critical component for maintaining legacy S5-100U automation infrastructure where program migration to newer platforms is not feasible . Because the SIMATIC S5 series has been fully discontinued for many years, this module is now extremely scarce in the spare parts market . For system integrators, this CPU provides a practical solution for restoring operations in established S5-100U-based systems without the cost and downtime of a complete system overhaul.