Siemens 6ES5340-5AA21 SIMATIC S5 340 RAM Memory Module

Features

-16K-instruction RAM capacity
-Rugged SIMATIC S5 module construction
-Hardware-configurable start address
-Eight selectable memory-inhibition blocks
-Word and byte address mapping
-SIMATIC S5 Series 340 architecture

Product Overview

The Siemens 6ES5340-5AA21 is a SIMATIC S5 Series 340 read/write RAM memory module for in the rugged module format. It provides storage for up to 16K instructions, corresponding to 16K words or 32 KB of addressable memory. This module is intended for control systems whose memory layout has been engineered around the SIMATIC S5 architecture. Its start address and usable memory sections are defined through hardware link settings. 

Technical Specifications

Benefits

-Provides 32 KB of writable program memory
-Offers twice the instruction capacity of the 6ES5340-5AA11
-Supports controlled placement within the system memory map
-Allows overlapping memory sections to be selectively disabled
-Facilitates program modification and commissioning work

Application Areas
SIMATIC S5 Control-System Maintenance--The module can be used when maintaining control installations designed around a SIMATIC S5 340 RAM memory board. Engineers should retain the original address map and reproduce the required socket-link configuration during replacement.

Industrial Machine Control--In compatible machinery, the 6ES5340-5AA21 stores the PLC program used for sequence control, interlocking, actuator operation and machine-status processing. Its writable RAM structure allows program corrections during commissioning and troubleshooting.

Machine-Tool and Integrated Control Systems--Siemens documentation describes the 6ES5 340 memory board within an integrated PC and machine-control environment. The configurable start address allows the RAM area to be coordinated with other program-memory sections in the system.

Frequently Asked Questions

1. Can the 6ES5340-5AA21 directly replace the 6ES5340-5AA11?
The two modules belong to the same S5 340 RAM family, but their capacities are different. The 6ES5340-5AA11 provides 8K instructions, while the 6ES5340-5AA21 provides 16K instructions. Before changing modules, verify the controller’s permitted memory range, the start-address links and every inhibited memory section.

2. Why might the controller not use the full 16K-word capacity?
Part of the RAM can be intentionally inhibited when its address range overlaps another RAM or EPROM area. On the 6ES5340-5AA21, socket 71 divides the available memory into eight blocks of 2K words, equivalent to 4 KB per block. An installed link disables the corresponding block.

3. How is the RAM start address configured?
The start address is selected through hardware links on socket 51. In the documented System 8 arrangement, the available settings run from 4K to 28K word addresses in 2K-word increments. Engineers should calculate the required address from the complete controller memory map before changing any links.