Siemens Simatic M7-400 Reference Manual page 624

Glossary
STARTUP
The STARTUP mode is traversed during the transition from STOP mode to RUN
mode.
STARTUP can be triggered by the ³ mode selector or following power-on or by
means of an operator input on the programming device.
Rebooting and restarting are the two different types of startup. Depending on the
position of the mode selector, either a reboot or restart is executed in the case of
the S7-400. A reboot is executed in the case of the M7-300/400.
STEP 7
Parameter assignment and programming software for the parameterization and
creation of user programs for SIMATIC S7 controllers.
Substitute value
Substitute values are values that can be output to the process when signal output
modules have failed or be used in the user program instead of a process value
when signal input modules have failed.
The substitute values can be assigned parameters by the user in STEP 7 (old
value retained, substitute value 0 or 1). They are values which the output(s) have
to output in the event of a CPU STOP.
SYNC
Control command of the ³ master to the ³ slave: freeze the outputs at their
current value.
System data block
SDBs (system data blocks) are data areas on the central processing unit which
contain system settings and module parameters. The system data blocks are
created and modified in STEP 7.
System diagnostics
System diagnostics is the detection, analysis and reporting of errors that occur
within the programmable controller. Examples of such errors are: program errors
or failures on modules. System errors can be indicated with LED displays or in
STEP 7.
System function
A system function (SFC) is a function integrated in the operating system of the
CPU that can be called in the STEP 7 user program like a function (³ FC), as
required.
Glossary-18
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07