Siemens 6ES5374-2FS21 | Memory Card

The Siemens 6ES5374-2FS21 stores your PLC program and system parameters safely. It serves as a reliable memory expansion for the SIMATIC S5 series. This card plugs directly into the CPU or interface module slot.

Technical specifications of Siemens 6ES5374-2FS21

Parameter	Specification
Brand	Siemens
Model	Siemens 6ES5374-2FS21
Product Family	SIMATIC S5
Category	Memory Card (EEPROM)
Memory Capacity	64 KB
Memory Technology	EEPROM (electrically erasable)
Write Cycles	Minimum 10,000 cycles
Data Retention	Over 10 years without power
Compatible CPUs	S5-115U, S5-135U, S5-155U
Dimensions (L x W x H)	Approx. 8.5 cm x 5.5 cm x 0.8 cm
Weight	Approx. 0.05 kg (50 grams)
Operating Temperature	0°C to 60°C

Detailed Technical Analysis

This memory card uses EEPROM technology for non-volatile storage. Therefore, it retains your program even after a complete power loss. The Siemens 6ES5374-2FS21 offers 64 kilobytes of usable space. This capacity handles most mid-sized S5 automation tasks comfortably.

Now let us examine its physical construction. The card contains a single PCB with surface-mounted memory chips. It has no moving parts or internal batteries. Consequently, you will never need to replace an energy storage component. The card draws minimal power from the PLC backplane.

You can write data to this module electrically. Unlike UV-EPROM cards, you do not need a separate erasing device. The Siemens 6ES5374-2FS21 supports over 10,000 write cycles. This durability allows frequent program updates during machine commissioning.

Installation and Compatibility Notes

The Siemens 6ES5374-2FS21 fits directly into the S5 CPU memory slot. It works with the S5-115U, S5-135U, and S5-155U processor families. Simply insert the card with the correct orientation. The PLC then recognizes the memory automatically at power-up.

For backup purposes, this card retains data for more than a decade. You can store a spare copy of your critical machine code safely. The Siemens 6ES5374-2FS21 weighs only 0.05 kilograms. Its compact size (8.5 x 5.5 x 0.8 cm) occupies minimal rack space.

Practical Applications

Engineers use this memory card for program backup and system recovery. It also simplifies machine retrofits. For example, you can pre-load the Siemens 6ES5374-2FS21 with a tested program offline. Then insert it into a new CPU for instant startup.

Summary

To conclude, the Siemens 6ES5374-2FS21 provides 64KB of non-volatile EEPROM storage. It has zero energy storage requirements and a 0.05kg weight. Choose this card to keep your SIMATIC S5 system running reliably.