Siemens S5-135U/155U Manual De Usuario

5-80

System Manual

C79000-G8576-C199-06

This section provides a summary

of the use of the 374 flash EPROM cards (known as the 374 memory
cards in the following) in the CPU 948, CPU 928B-3UB21 and
CPU 928-3UA21

and of the technical specifications.

The 374 memory card serves as a storage medium for user programs and user
data. It contains electrically erasable flash EPROMs.

The 374 memory card is available in the following capacities:

256 Kbytes

512 Kbytes

1024 Kbytes

2048 Kbytes

4096 Kbytes

The order numbers for the SIMATIC S5 memory cards can be found in the
ordering information.

You can program and erase the 374 memory card off-line on the SIMATIC S5
programmers. The link to the PG is provided by a special connector or
programming  adapter, into which the memory card is inserted. A description
of EPROM programming can be found in the STEP 5 manual.

Memory cards can be inserted and removed at any time, even whilst the CPU
is running, as long as they are not being accessed (see the CPU 948
Programming Guide).

The contents of the memory cards are only copied automatically into the
internal RAM of the CPU upon overall reset of the CPU.

Memory cards are electrically erasable.

CPUs, Memory Cards, Memory Submodules, Interface Submodules