Siemens 6ES5377-0AA21 Memory Submodule

Engineered for SIMATIC S5 PLC Program Storage

This submodule stores user programs and system parameters securely. It provides non-volatile memory for the Siemens 6ES5377-0AA21 unit. You will find this memory card in legacy SIMATIC S5 systems. Unlike RAM modules, this version uses EPROM technology for data retention. It retains all program data without any battery backup.

Technical Specifications & Physical Dimensions

We designed this memory submodule for long-term program storage. The table below presents all verified technical specifications.

Parameter	Specification
Memory Capacity	8 KB (64 Kbit)
Memory Type	UV-EPROM (erasable programmable)
Package Type	28-pin DIP (dual in-line)
Physical Dimensions	38mm x 14mm x 9mm
Total Weight	12 grams
Operating Voltage	5V DC (±5%)
Access Time	300 nanoseconds maximum

Functional Architecture and Data Organization

This submodule plugs directly into the S5 CPU’s memory socket. It uses a standard JEDEC pinout for compatibility. You cannot write new data without a UV eraser. Moreover, the module includes a quartz window for erasure. This window allows ultraviolet light to clear existing contents. Consequently, you can reprogram the chip after 20 minutes of UV exposure.

Installation and Operational Guidelines

The Siemens 6ES5377-0AA21 retains data for over 10 years. It requires 12.5V on pin 1 for programming mode. You must align the notch with the socket indicator. Always cover the quartz window with an opaque label after programming. This practice prevents accidental erasure from ambient light. Furthermore, the submodule supports checksum verification during CPU power-up. This feature confirms the integrity of stored program data.

Physical Characteristics and Environmental Limits

This memory submodule features a ceramic body with glass window. Its lightweight 12 gram design allows for easy handling. The layout follows Siemens standard memory module specifications. Therefore, it fits securely into any S5 CPU or expansion unit. The module requires no external power for data retention. In addition, it maintains stable operation between 0°C and 60°C ambient temperature. You can store this submodule safely between -40°C and 85°C.