Siemens 6ES5355-3UA11 Memory Module

Physical Dimensions and Mechanical Layout

The Siemens 6ES5355-3UA11 stores user programs for SIMATIC S5 processors. This module measures 250mm in height, 25mm in width, and 150mm in depth. You can insert this unit into any S5 CPU memory slot without special tools. The module weighs 0.28 kilograms , making it easy to handle during installation.

Internal Architecture and Component Density

The Siemens 6ES5355-3UA11 contains 86 individual components on its two-layer PCB. Sixteen EPROM chips provide non-volatile storage for user application programs. Four CMOS RAM chips handle variable data and system flags during operation. Additionally, a lithium backup battery preserves RAM contents when the system powers down.

Energy Storage and Data Retention

This memory module stores 32.4 joules in its lithium backup battery. The battery maintains RAM data integrity for up to 180 days without external power. The module also includes four filter capacitors that suppress power supply noise. Consequently, your program and data remain safe during extended system shutdowns.

Parameter	Value	Unit
Dimensions (H x W x D)	250 x 25 x 150	mm
Weight	0.28	kg
PCB layer count	2	layers
Total components	86	pieces
EPROM memory chips	16	units
CMOS RAM chips	4	units
Lithium backup battery	1	unit
Filter capacitors	4	units
Total battery energy storage	32.4	J
RAM data retention time	180	days
EPROM capacity	64	KB
RAM capacity	8	KB
Total memory	72	KB
Memory access time	200	ns
Operating voltage	5	V DC
Active current draw	20	mA
Standby current draw	2	µA
Operating temperature	0 to 60	°C
Storage temperature	-20 to 70	°C
Compatible CPU models	S5-115U, 135U, 155U	–

Interface and Connectivity Features

The Siemens 6ES5355-3UA11 provides 34 gold-plated edge connectors for CPU interface. A polarization notch prevents incorrect insertion into the memory slot. The module uses zero insertion force for easy removal and replacement. The PCB includes locking tabs that snap into place for secure retention.

Memory Organization and Addressing

This module partitions its 72KB into program blocks and data blocks. The EPROM section holds user program logic that does not change during operation. The RAM section stores flags, timers, counters, and variable values dynamically. The CPU accesses both memory types with a 200ns access time for fast execution.

Program Storage and Transfer

You can program the Siemens 6ES5355-3UA11 using a standard EPROM programmer with an adapter. The module accepts STEP 5 object code downloaded from a programming device. You can copy program data between two modules using a CPU function. The unit supports firmware updates without replacing the entire module.

Battery Backup and Monitoring

The internal lithium battery automatically backs up RAM during power-off conditions. This battery has a 10-year shelf life under normal storage conditions. A battery monitoring circuit warns the CPU when voltage drops below 2.5V. The CPU then sets a system flag that you can monitor in your user program.

Compatibility and System Integration

This memory module works with S5-115U, S5-135U, and S5-155U CPU models. You must install this module in the designated memory slot of the selected CPU. The unit supports programs up to 72KB depending on CPU model limits. The module requires no configuration after installation.

Environmental Specifications and Compliance

You can operate this memory module from 0°C to 60°C ambient temperature without derating. Storage temperature ranges from -20°C to 70°C for long-term preservation. Non-condensing humidity tolerance spans 10% to 90% for industrial environments. This unit meets DIN 19240 standards for programmable controller memory components.