Table of Contents
Advertisement
Error indication:
The error indication is one of the possible responses of the operating system to a->
runtime error. The other possible reactions are: -> error reaction in the
userprogram, STOP mode of the CPU.
Error reaction:
Reaction to a -> runtime error. The operating system can respond in the
followingways: conversion of the programmable controller to the STOP mode, call
of anorganization block in which the user can program a response or display of
theerror.
Flash EPROM:
FEPROMs are the same as electrically erasable EEPROMS in that they can
retaindata in the event of a power failure, but they can be erased much more
quickly(FEPROM = Flash Erasable Programmable Read Only Memory). They are
used on -> memory cards.
Free cycle:
The free cycle consists of the basic tasks for priority class 1: writing to the outputs,
reading theinputs, executing OB 1, and completing the sleep time requirement
before triggering the next freecycle. The controller executes these tasks at the
base, or lowest, internal priority level for executingthe OBs. (Priority level in this
context refers to OB priority classes, not the operating system prioritylevel.)
Function block:
A function block (FB) in accordance with IEC 1131-3 is a -> logic block with ->static
data. An FB allows parameters to be passed in the user program. Functionblocks
are therefore suitable for programming complex functions, e.g. closed-loopcontrols,
mode selections, which are repeated frequently.
Global data:
Global data are data that can be addressed from every logic block (FC, FB, OB).
Specifically, these are bit memory (M), inputs (I), outputs (Q), timers (T), counters
(C) and data blocks (DB). Both absolute access and symbolic access of global
data are possible.
Global data communication:
Shared data communication is a procedure used to transfer shared data
betweenCPUs (without CFBs).
Windows Automation Center, WinAC Slot Version 4.0
Hardware Installation and Operating Manual, Edition 02/2006, A5E00273194-02
Glossary
175
Advertisement
Table of Contents
