Festo Контроллеры двигателя SFC-LAC - Manual (Page 245)

B. Parametrizing via field bus
B−25
Festo GDCP−SFC−LACI−DN−EN en 0812NH
Notes on representing the finite status machine
The transition T3 changes to state S4, which itself contains its
own sub−state machine, the states of which are marked with
SAx" and the transitions of that are marked with TAx". This
enables an equivalent circuit diagram to be used, in which the
internal states SAx are omitted:
Switched off
S1 Controller
switched on
S4
Drive enabled
S2 Drive locked
S5 Reaction to
fault
S6 Malfunction
From all statuses
Operation
enabled
T6
T2
T5
T3
T4
T1
T7*
T8
T10
T9
S5
T11
S4
Fig. B/2: Finite state machine equivalent circuit diagram
Transitions T4, T6 and T7* are executed from every sub−state
SAx and automatically have a higher priority than any
transition TAx. Such a structure is a simplification. It is not
therefore necessary to define out of each SAx state a
separate transition as per S3 for the reaction to STOP
(S3:Ădrive held stationary).
Reaction to faults
T7 (Fault recognised") has the highest priority and receives
the asterisk āā*āā".
T7 is then derived from S5 and S6 when an error of higher
priority occurs. As a result, a slight error can displace a
serious error.