Glossary
Glossary-13
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
A system function block (SFB) is a function block integrated in the CPU
operating system which can be called in the STEP 7 user program
when required, just like a function block (FB).
The system memory is integrated in the CPU and executed in the form
of RAM. The address areas (timers, counters, bit memory, etc.) and
data areas required internally by the operating system (for example,
backup for communication) are stored in the system memory.
T
The time-delay interrupt belongs to one of the priority classes in
SIMATIC S7-400 program processing. It is generated after expiry of a
time started in the user program. A corresponding organization block is
then executed.
The time-of-day interrupt belongs to a priotity class in SIMATIC S7-400
program processing. It is generated depending on a certain date (or
daily) and time of day (for example, 9:50 or hourly, per minute). A
corresponding organization block is then executed.
Timers are an area in the system memory of the CPU. The contents of
these timers are updated by the operating system asynchronously to
the user program. You can use STEP 7 instructions to define the exact
function of the timer (for example, on-delay timer) and start processing
it (Start).
Sum of currents of all output channels of a digital output module.
Speed of data transmission in bits per second
U
Without galvanic connection to ground.
The user memory contains logic blocks and data blocks of the user
program. The user memory can either be intergrated in the CPU or can
be plugged in on memory card or memory submodules. In general,
however, the user program is executed from the work memory (RAM)
of the CPU.
System Function
Block (SFB)
System Memory
Time-Delay
Interrupt
Time-Of-Day
Interrupt
Timer (T)
Total Current
Transmission Rate
Ungrounded
User Memory
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