Siemens 6ES5 340-3KB41 SIMATIC S5 RAM Memory Module

Features

-64 KiB RAM capacity
-32,768-instruction storage
-SIMATIC S5 user-memory expansion
-Battery-backed CMOS memory
-Configurable memory addressing
-Backplane-mounted module construction

Product Overview

The Siemens 6ES5 340-3KB41 is a SIMATIC S5 Series 340 RAM memory module used to expand the user-program memory of compatible programmable controller systems. Siemens documentation lists this module with a capacity of 32 × 2¹⁰ instructions, equal to 32,768 instructions or approximately 64 KiB of byte-addressable storage. The module provides writable memory for control-program instructions and associated user data. Its RAM contents depend on the controller’s memory-backup arrangement when the main power supply is removed. For this reason, the PLC program should be archived before the module, controller power supply or backup battery is serviced. Siemens documents the 6ES5 340-3KB41 in the SIMATIC S5-130W Version B system. Historical system documentation also identifies it as a memory-module option for S5-150U configurations. Compatibility must still be checked against the exact CPU, rack version, available address range and existing memory layout.

Technical Specifications

Benefits

-Expands available PLC user-program memory
-Provides writable program storage
-Supports established SIMATIC S5 architectures
-Preserves the original controller memory structure
-Allows exact catalog-number matching
-Supports maintenance of legacy machine logic

Application Areas
SIMATIC S5-130W Memory Expansion: The 6ES5 340-3KB41 can expand the uer-program memory of a documented S5-130W Version B controller. The available CPU address range and the module’s addressing configuration must be checked before installation.

Machine-Control Program Storage: The RAM module can hold PLC logic used for sequences, interlocking, machine operation and production control. Continued retention during a power interruption depends on the controller’s functioning memory-backup system.

Memory-Configuration Restoration: The module can be used when restoring an established PLC memory arrangement after rack, CPU or power-supply maintenance. The original address configuration and archived program must be verified before startup.

Frequently Asked Questions

1. Why is the module described as both 32K instructions and 64 KiB?
Siemens lists the capacity as 32 × 2¹⁰ instructions. With two bytes used for each instruction-storage location, this corresponds to 65,536 bytes, or 64 KiB.

2. Will the program remain in memory when controller power is removed?
The module uses RAM, so program retention depends on the controller’s backup supply and battery condition. The PLC program should be archived before power-supply work, battery replacement or module removal.

3. Can the module be installed in any SIMATIC S5 controller?
No. Siemens documents it for specific S5 system configurations, including the S5-130W Version B, and historical records associate it with S5-150U configurations. The CPU type, rack, memory addressing and supported capacity must be checked in the relevant controller manual.