Siemens 6ES5374-2KH21 – Memory Card for SIMATIC S5 Program Storage

The Siemens 6ES5374-2KH21 stores user programs in non-volatile EEPROM technology. This memory card measures 85 mm in height and 55 mm in width. It has a depth of 8 mm, so it fits into standard card slots easily. The unit weighs 0.04 kg, making handling and insertion effortless.

Storage Capacity and Memory Technology

This memory card holds 64 kB of user program data in EEPROM technology. The Siemens 6ES5374-2KH21 retains stored data for over 10 years without any battery. You can electrically erase and reprogram this card up to 100,000 times. The card stores complete program blocks, data blocks, and system parameters. It requires no UV eraser or special programming voltage for updates.

Internal Architecture and Component Layout

The card contains a single PCB with two EEPROM chips and decoding logic. The Siemens 6ES5374-2KH21 includes a write-protect switch for data security. A 40-pin edge connector interfaces with the S5 CPU card slot. The card draws power only during read and write operations from the CPU. It stores 4.7 µF of capacitance for signal filtering during access.

Programming Requirements and Compatibility

You can program this memory card using any standard S5 programming device. The Siemens 6ES5374-2KH21 requires only 5V DC from the programming port. The card works with all S5 CPU models from 115U to 155U series. It also fits into S5 expansion racks for remote program storage. A red LED indicates when write operations are in progress.

Environmental Tolerance and Physical Design

The Siemens 6ES5374-2KH21 operates reliably from 0°C to 60°C ambient temperature. It tolerates humidity levels up to 95 percent without any condensation issues. The card withstands vibration up to 2g from 10 to 500 Hz. A plastic case protects the internal components from static discharge. The card includes a label area for handwritten identification markings.

Below is a complete summary of its technical specifications.

The Siemens 6ES5374-2KH21 replaces older EPROM cards in SIMATIC S5 systems. You do not need any UV eraser or special programmer for this card. This unit also supports in-circuit programming without removing it from the CPU. Consequently, it provides secure and reusable program storage for S5 controllers.