User Manual

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 ar e marked with TAx". This
enables an equivalent circuit diagram to be used, in which the
internal stat es 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 highe
r priority than any
transition TAx. Such a structure is a simplification. It is not
therefore necessary to define out of each SAx state a
s
eparate transition as per S3 for the reaction to STOP
(S3:drive held stationary).
Reaction to faults
T7 (Fault recognised") has the highest priority and receives
the ast
erisk *".
T7 is then derived from S5 and S6 when an error of higher
priority occurs. As a result, a slight error can displace a
se
rious error.