Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 748)

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746 DMS 4.1 EN 03/2011 TD29
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The following implicit variables (flags) can be used. For this purpose they must be
declared and activated in the SFC Settings:
SFCInit: BOOL; If this variable gets TRUE, the sequential function chart will be set back to
the Init step. All steps and actions and other SFC flags will be reset
(initialization). The Init step will remain active, but not be executed as long
as the variable is TRUE. SFCInit must be set back to FALSE in order to get
back to normal processing.
SFCReset: BOOL; This variable behaves similarly to SFCInit. Unlike the latter however, further
processing takes place after the initialization of the Init step. Thus in this
case for example a reset to FALSE of the SFCReset flag could be done in the
Init step.
SFCError: BOOL; As soon as any timeout occurs at one of the steps in the SFC, this variable
will get TRUE. Precondition: SFCEnableLimit must be TRUE. Notice that any
further timeout can not be registered before a reset of SFCError. SFCError
must be defined, if you want to use the other time-controlling flags
(SFCErrorStep, SFCErrorPOU, SFCQuitError).
SFCEnableLimit: BOOL; This variable can be used for the explicit activation (TRUE) and deactivation
(FALS) of the time control in steps via SFCError. This means, that If this
variable is declared and activated (SFC Settings) then it must be set TRUE in
order to get SFCError working. Otherwise any timeouts of the steps will not
be registered. The usage might be reasonable during start-ups or at
manual operation. If the variable is not defined, SFCError will work
automatically. Of course as a precondition SFCError must be defined!
SFCErrorStep: STRING; This variable stores the name of a step at which a timeout was registered
by SFCError. timeout. Precondition: SFCError must be defined!
SFCErrorPOU: STRING; This variable stores the name of the SFC POU in which a timeout has
occurred. Precondition: SFCError must be defined!
SFCQuitError: BOOL; As long as this variable is TRUE, the execution of the SFC diagram is
stopped and variable SFCError will be reset. As soon as the variable has
been reset to FALSE, all current time states in the active steps will be reset.
Precondition: SFCError must be defined!
SFCPause: BOOL; As long as this variable is TRUE, the execution of the SFC diagram is
stopped.
SFCTrans: BOOL; This variable gets TRUE, as soon as a transition is actuated.
SFCCurrentStep: STRING; This variable stores the name of the currently active step, independently of
the time monitoring. In case of simultaneous sequences the name of the
outer right step will be registered.
SFCTip, SFCTipMode: BOOL; This variables allow using the inching mode within the current chart. When
this mode has been switched on by SFCTipMode=TRUE, you can only skip to
the next step by setting SFCTip=TRUE (rising edge). As long as SFCTipMode
is set to FALSE, it is possible to skip by the transitions.