Siemens 6ES5340-3KB21 Programmable Logic Controller Module

Siemens 6ES5340-3KB21 is a SIMATIC S5 340 memory module in the compact RAM version, providing 32 KB of RAM to store ladder logic, data blocks, and configuration data for S5-130 and S5-150 PLCs. This RAM memory module installs in the 340 memory module slot to extend the controller’s available memory, enabling larger user programs and additional data storage within legacy automation systems. Compatible with the SIMATIC S5 family, the 6ES5340-3KB21 is identified by the part number 6ES5340-3KB21 and is used to upgrade or replace memory in S5-130/150 configurations, including equipment operating on older rack-based layouts. Typical applications include retrofits, maintenance, and spares for plants that rely on Siemens S5 controllers, where memory constraints limit program size or data logging capacity.