Application; Cpu 948; Technical Description - Siemens S5-155U System Manual

CPU 948

5.1 CPU 948
5.1.1

Technical Description

Application

5 - 6
This section contains the hardware description and the technical
specifications of the CPU 948.
Details on programming the CPU 948 can be found in the CPU 948
Programming Guide.
This section contains information on the application, design and
structure of the CPU 948.
You can use the CPU 948 in single and multiprocessor operation in
the S5-135U/155U central controller (see Chapter 6).
There are two versions of CPU 948:
• • The CPU 948-1 offers 640 Kbytes of internal user memory (RAM).
• • The CPU 948-2 offers 1664 Kbytes of internal user memory
(RAM).
A SIMATIC S5 flash EPROM memory card (known as a memory
card for short in the following) can be inserted in the CPU 948 as the
storage medium for user program and user data. The contents of the
memory card are copied into the internal RAM of the CPU upon
overall reset.
The programming language is STEP 5 (LAD, CSF, STL, SCL). The
CPU 948 processes all STEP 5 operations at very high speed, and uses
fast floating-point arithmetic.
The following program processing levels are possible:
• • Cyclic
• • Time-controlled (9 different timebases, real-time controlled,
timeout)
• • Interrupt-driven from the S5 bus (8 process interrupts at block
boundaries via IB0 or, alternatively, 4 system interrupts)
• • Soft STOP.
System Manual
C79000-B8576-C199-03