Siemens SIMATIC S5 Modules: 6ES5103-8MA03

Technical Dossier

Product Details And Specifications

Siemens SIMATIC S5 Series Technical Notes

The Siemens SIMATIC S5 programmable logic controller (PLC) series represents one of the most widely deployed automation platforms in global heavy industry. Installed across petrochemical refineries, nuclear power stations, chemical processing plants, steel mills, and offshore platforms from the 1980s through the early 2000s, the S5 architecture established the baseline for industrial automation reliability in continuous-process environments. Facilities operating under IEC 61511 (functional safety) and ISO 55000 (asset management) frameworks continue to maintain S5-based control systems as the cost and risk of full migration to S7 or TIA Portal platforms remains prohibitive. The installed base of SIMATIC S5 hardware globally is estimated in the hundreds of thousands of racks, making spare parts availability a critical operational concern for maintenance engineers worldwide.

The Evolution of SIMATIC S5 Architecture

The SIMATIC S5 family was introduced by Siemens in the late 1970s and underwent continuous development through four primary hardware generations. The earliest S5-90U and S5-95U compact controllers used proprietary STEP 5 programming and a parallel backplane bus. The mid-generation S5-100U, S5-115U, S5-135U, and S5-155U systems introduced modular rack-based architectures with the S5 bus (also referred to as the P-bus and C-bus), enabling distributed I/O expansion and multi-CPU configurations. The S5-115U platform, which includes the 6ES5103-8MA03 CPU module, became the dominant mid-range controller for process industries due to its balance of processing capacity, memory addressability, and I/O density.

Siemens officially announced end-of-production for the SIMATIC S5 series in 1994, with extended spare parts support running through 2013. As of 2026, all S5 hardware is classified as obsolete (End of Life / EOL). No new production runs are available from Siemens. The migration path recommended by Siemens is to SIMATIC S7-300, S7-400, or S7-1500 via the S5/S7 converter tool and STEP 7 / TIA Portal. However, due to the complexity of STEP 5 ladder logic conversion and the cost of I/O rewiring, a significant portion of the installed base remains on S5 hardware under lifecycle extension programs.

Compatibility note: S5 modules are not electrically or logically interchangeable with S7 hardware. The S5 bus protocol, memory addressing (bit, byte, word, timer, counter), and programming environment (STEP 5 v7.x) are entirely distinct from S7 systems. Cross-generation substitution requires hardware gateways or full system replacement.

SIMATIC S5 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced modules within the SIMATIC S5 ecosystem. Modules are classified by functional category.

CPU / Processor Modules

• 6ES5103-8MA03: S5-115U CPU 103, 16KB RAM, STEP 5 compatible, central processing unit for mid-range S5 rack systems.
• 6ES5095-8MA01: S5-90U/95U compact CPU, integrated I/O, suitable for small standalone applications.
• 6ES5100-8MA02: S5-100U CPU 100, entry-level modular CPU for the S5-100U rack system.
• 6ES5101-8UA13: S5-115U CPU 101, predecessor to the 103 series, 6KB program memory.
• 6ES5102-8MA02: S5-115U CPU 102, 8KB RAM, intermediate processing capacity.
• 6ES5115-8MA02: S5-115U CPU 115, high-performance variant with extended addressing range.
• 6ES5135-8MA02: S5-135U CPU 135, large-scale process controller with multi-tasking capability.
• 6ES5155-8MA11: S5-155U CPU 155, top-tier S5 processor for complex, high-I/O-count applications.

Digital Input (DI) Modules

• 6ES5421-8MA11: 32-channel 24VDC digital input module, standard S5-115U rack mounting.
• 6ES5430-8MA11: 16-channel 24VDC digital input module, isolated, for S5-115U/135U systems.
• 6ES5431-8MA11: 16-channel 120VAC digital input module, for high-voltage field signal interfacing.

Digital Output (DO) Modules

• 6ES5451-8MA11: 32-channel 24VDC digital output module, transistor output, S5-115U compatible.
• 6ES5452-8MA11: 16-channel relay output module, for switching inductive loads in S5 systems.

Analog Input / Output (AI/AO) Modules

• 6ES5464-8MA11: 8-channel analog input module, ±10V / 4–20mA, 12-bit resolution, S5-115U.
• 6ES5470-8MA12: 4-channel analog output module, 12-bit DAC, voltage and current output modes.

Communication & Interface Modules

• 6ES5734-1BD20: SINEC L1 communication processor, serial bus interface for S5 distributed I/O.
• 6ES5318-8MA12: Interface module (IM 318), connects central rack to expansion racks via S5 C-bus.
• 6ES5316-8MA12: Interface module (IM 316), send/receive pair for multi-rack S5-115U configurations.

Power Supply Modules

• 6ES5955-3LC41: 24VDC / 6A power supply unit for S5-115U rack, input 120/230VAC selectable.
• 6ES5955-3NC41: 24VDC / 10A power supply, high-current variant for fully populated S5-115U racks.

Quality Control for the SIMATIC S5 Range

All SIMATIC S5 modules processed by DriveKNMS undergo a structured multi-stage inspection protocol prior to dispatch. The S5 backplane bus architecture requires verification of both the P-bus (peripheral bus, for I/O data) and C-bus (communication bus, for inter-CPU and IM communication) signal integrity, which cannot be assessed through visual inspection alone.

The DriveKNMS S5 test procedure includes: (1) Visual inspection for physical damage, corrosion on edge connectors, and capacitor condition; (2) Power-on functional test using a reference S5-115U rack with known-good CPU and power supply; (3) STEP 5 diagnostic read-out to verify module identification, firmware version, and error register status; (4) I/O channel-level verification for all DI, DO, AI, and AO modules using calibrated signal sources and measurement equipment; (5) Communication module loopback testing for SINEC L1 and IM interface modules; (6) 48-hour burn-in cycle under operational load conditions for CPU and power supply modules. Modules that pass all stages are issued a DriveKNMS test certificate and shipped with anti-static packaging and humidity indicator cards.