Technical data

Table Of Contents
Glossary
System Software for S7-300/400 System and Standard Functions- Volume 2/2
A5E00739858-01
Glossary-15
System Diagnostic Event
An entry which is made in the diagnostic buffer of the CPU and is used to initialize
operating system.
System Function (SFC)
A system function (SFC) is a function which is integrated in the CPU operating
system and can be called in the STEP 7 user program as required.
System Function Block (SFB)
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.
Three-Step Controller
A controller that can only adopt three discrete states; for example, "heat - off cool"
or "right - stop - left" (step controller).
Time-Delay Interrupt
The time-delay interrupt belongs to one of the priority classes used in SIMATIC S7
program processing. This interrupt is generated in the user program after a
specified time has elapsed and is processed in the associated organization block.
Tool
A software feature used for configuring and programming.
Two-step Controller
A two-step controller is a controller that can only set two states for the manipulated
variable (for example, on - off).
User-Defined Diagnostics
The detection and evaluation of user-defined diagnostic events.
User-Defined Diagnostic Event
A diagnostic event detected by the user which can be placed into the diagnostic
buffer (with SFC 52).
User-Defined Diagnostic Message
A message reporting the occurrence of a user-defined diagnostic event.