Siemens SIMATIC S5 16K Word Memory Module

Description

The 6ES5355-3UA11 is a memory submodule from the Siemens SIMATIC S5 series, specifically the model 355. This RAM module provides a capacity of 16K words (32 Kbytes) and is essential for storing user programs and data in S5-135U and S5-155U PLC systems. It is a critical component for maintaining or repairing legacy automation systems that rely on the robust S5 platform.

Specifications

• Manufacturer: Siemens
• Product Line: SIMATIC S5
• Product Type: Memory Submodule
• Model: 355
• Order Number (MLFB): 6ES5355-3UA11
• Memory Type: RAM (Random Access Memory)
• Memory Capacity: 16 K Words (equivalent to 32 Kbytes)
• Compatibility: For S5-135U and S5-155U Central Processing Units

Label Info

• Siemens SIMATIC S5 Speicherbaugruppe
• 355 Memory Submodule
• Version: 04

Application

This module is used in a wide range of industrial applications controlled by Siemens S5-135U/155U PLCs, including manufacturing lines, process control, and material handling systems. It allows for the storage and execution of complex control logic.

Country of Origin

This product is manufactured by Siemens in Germany.

CO2 Impact

Choosing a used or refurbished component like this one prevents the emission of approximately 12.0 kg of CO2 compared to manufacturing a new one. This saving is comparable to the emissions from driving a standard car for 60 kilometers.

Availability

This is an obsolete item, but it is available from our stock. Order now from PLC2Day for expert support and fast delivery.

FAQ

Question?

What is the battery life for data retention on this RAM module?

The 6ES5355-3UA11 is a RAM module and relies on a backup battery located in the PLC's power supply unit (e.g., 6ES5980-0MA11) for data retention during power-off states. The battery life is typically 1-2 years, and it should be replaced preventatively to avoid data loss.

Can this module be used in any SIMATIC S5 CPU?

No, this submodule is specifically designed for the S5-135U and S5-155U series PLCs. It is not compatible with smaller S5 systems like the S5-95U or S5-115U, which use different memory card formats.

Is this an EPROM or RAM module, and what is the difference?

This is a RAM (Random Access Memory) submodule. RAM is volatile, meaning it requires power from a backup battery to retain its data. It's used for programs that may need frequent changes. An EPROM (Erasable Programmable Read-Only Memory) module is non-volatile and holds its program without a battery, but requires a special UV eraser and programmer to make changes.

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Last Update: Friday, March 13, 2026