Siemens 6ES5375-0LD21 Memory Module

Program and Data Storage for S5 Controllers

The Siemens 6ES5375-0LD21 memory module expands the storage capacity of S5-115U and S5-135U programmable controllers. This module provides reliable non-volatile memory for user programs, system parameters, and recipe data. Industrial facilities require secure storage solutions, and this module meets those demands effectively.

Memory Technology and Capacity Details

This memory module employs CMOS RAM technology with a lithium battery backup for data preservation. The module offers 32 kilobytes of total storage, organized into 16 kilobytes for program code and 16 kilobytes for data blocks. An integrated battery monitoring circuit provides early warning of low voltage conditions. Additionally, the module supports read and write operations at speeds under 200 nanoseconds.

Battery Backup and Data Integrity Features

The replaceable lithium battery automatically maintains memory contents when the system power drops. This battery provides a minimum retention period of 300 days, even in unpowered storage conditions. A front-panel LED illuminates approximately 30 days before the battery reaches end-of-life. The module also performs automatic parity checking on all stored data during each read operation.

Physical Construction and Installation

This memory module features a compact, lightweight design weighing only 70 grams. The plastic housing with keyed pins ensures correct orientation during CPU installation. A removable cover protects the battery compartment from dust and accidental access. The gold-plated edge connector guarantees reliable electrical contact over many insertion cycles. Furthermore, the module’s small footprint allows installation even in densely populated rack configurations.

Operational Advantages and System Performance

The Siemens 6ES5375-0LD21 enables rapid program modifications without EPROM erasure or programming equipment. Users can download modified logic directly to the module from the programming terminal. This flexibility significantly reduces commissioning time and simplifies debugging processes. The module also stores time-of-day clock settings and diagnostic history for later analysis.

Compatibility and Replacement Guidelines

This memory module fits all S5-115U and S5-135U CPUs with standard memory cartridge slots. You can replace the module while the system remains powered, provided you follow the hot-swap procedure. Always verify that your CPU firmware supports 32 KB memory addressing before installation. For extended retention requirements, consider ordering spare batteries and replacing them annually. Handle the module with proper ESD precautions to avoid internal circuit damage.