Siemens Simatic S5 I/O and CPU Module Collection

This offering includes a selection of Siemens Simatic S5 automation components, comprising CPU units and digital input/output modules suitable for S5-115U and S5-135U rack systems. The S5 series is a legacy programmable logic controller platform widely used in industrial applications from the 1980s through the early 2000s. These modules are intended for maintenance, repair, and expansion of existing S5-based installations. The set includes various I/O modules and central processing units, allowing operators to keep older equipment running or to build spares inventory.

Typical Components Included

While the exact composition may vary, Simatic S5 modules typically include:

• CPU modules (e.g., 6ES5952-xxxx, 6ES5928-xxxx, 6ES5941-xxxx) for S5-115U and S5-135U racks. They feature onboard EPROM or RAM memory (battery-backed) and run the S5 STEP 5 operating system.

• Digital input modules (e.g., 6ES5421-8MA11, 6ES5422-8MA11) with 16 or 32 channels, 24 V DC or 120 V AC versions.

• Digital output modules (e.g., 6ES5451-8MA11, 6ES5452-8MA11) with transistor or relay outputs.

• Analog input/output modules (occasionally) with 4/8 channels.

• Communication modules (e.g., 6ES5308-3UB11) for SINEC L1 or H1 networks.

Technical Characteristics (General)

Simatic S5 modules are designed for installation in S5-100U, S5-115U, and S5-135U racks. The racks provide a passive backplane with a proprietary bus. Modules are 90 mm wide (single-slot) or double-slot. Power supply is 5 V DC (logic) and 24 V DC (field) from the rack. I/O addressing is via slot-based addressing (e.g., 0.0 to 127.7). The CPU modules run STEP 5 software, which can be programmed using PG 615 or PG 750 programming devices with software like STEP 5. Program storage can be in EPROM (cassette) or RAM (with lithium battery backup). Typical execution speed for basic instructions is 1 µs to 0.5 µs per operation depending on CPU model.

Applications and Use Cases

Simatic S5 systems are still in operation in many factories, especially in automotive, glass, paper, and energy sectors. These modules are used to replace failed components in legacy machines without requiring a full control upgrade. They are also used by system integrators for bridging to newer S7 systems via PROFIBUS (using an S5-to-S7 gateway). The modules listed here are functional pulls from decommissioned equipment or surplus stock, verified to be in working condition.

Installation Notes

Before inserting modules, verify that the rack’s power supply is turned off. Insert the module into the correct slot, ensuring the guide rails align with the board edges. Push firmly until the module clicks into the backplane connectors. Secure with the front screws. For CPU modules, insert the EPROM cassette (if used) or ensure the battery is fresh. Set the CPU’s mode switch to STOP, power on, then load the program via the programming port (15-pin D-sub). For I/O modules, wiring is via screw terminal blocks (20- or 40-pin). Always check for correct voltage compatibility (e.g., 24 V DC input modules should not be connected to 120 V AC).

Compatibility

The modules listed are compatible with the following racks:

• S5-115U racks: 6ES5955-xxxx, 6ES5956-xxxx

• S5-135U racks: 6ES5950-xxxx, 6ES5951-xxxx

Check the specific model numbers of the modules against the rack’s configuration manual to ensure proper fit and addressing.

Environmental and Compliance

These modules are designed for industrial use with operating temperature 0°C to 60°C. They are no longer in production but remain compliant with the electromagnetic standards of their era. They are not RoHS compliant (older lead-based solder may be present).

Conclusion

The Siemens Simatic S5 CPU and I/O modules provide a valuable resource for maintaining legacy automation systems. With proper handling and installation, they can extend the service life of S5-based control systems.