User Memory; Pg Interface Si1 - Siemens S5-155U System Manual

CPU 928B

User memory

PG Interface SI1

5 - 22
You require a user memory submodule (RAM or EPROM) for storage
of your program. You can store up to 64 Kbytes of code and data
blocks here. For data blocks, the CPU 928B additionally has an
integrated DB RAM of 46 3/4 Kbytes.
A description of the memory submodules can be found in Sections 5.6
and 5.7; order numbers are given in the ordering information.
There are two independent interfaces on the front of the CPU 928B.
You can connect programmers and OPs to the first interface. This PG
interface SI1 is permanently installed on the CPU.
You can use PG interface SI1 either via the front connector of the
CPU 928B or via the front connector of the 923C coordinator module.
Note
Simultaneous operation of PG interface SI1 via the front
connector of the CPU 928B and of the coordinator is not possible.
Electrically, it is merely a PG interface which can be operated via
two different terminals. Switching the programmer online without
a job request is already sufficient to operate the interface.
If you wish to utilize a second PG interface for connection of a
PG or OP, the connection must be made via the second PG
interface with the PG submodule.
Apart from PG interface SI1, the second interface SI2 can also be used
as a PG interface in parallel with the first one. You can only use the
second PG interface via the front connector of the PG submodule on
the CPU 928B.
A detailed description of operations with the two PG interfaces can be
found in the CPU 928B Programming Guide.
The connection to the PG can be established with the CPU in any
operational state.
System Manual
C79000-B8576-C199-03