Siemens 353, Руководство пользователя, Страница: 113 / 246

UM353-1B Function Blocks
April 2012 3-83
3.2.77 RSF_ - RS Flip-Flop
RSF_ function blocks perform a reset dominant flip-flop
function as detailed in the truth table. An unused S input
will be set high (1) and an unused R input will be set low
(0).
POWER UP - During a warm start, when PU LAST is set to
YES, the block will initialize at the input/output states at the
instant power down occurred. A cold start will initialize the
input/output states to 0.
3.2.78 RTG_ - Rising Edge Trigger
RTG_
function blocks provide a high (1) output for one scan
cycle each time input P transitions from a low (0) to a high
(1).
BLOCK DIAGRAM
R
O1
S
RS FLIP-FLOP TRUTH TABLE
S R
LO O1
1
0
0
0
X X
X 1
0
1 0
0 0 0
1
1
S - SET Input
R - RESET Input
O1 - O utput
LO - Last O utput
O
utput
1
R eset
S et
X (don't care)
.
.
BLOCK DIAGRAM
O utput 1
P
O1
P ulse Input
.
.
R eset
RS FLIP-FLOP
O1
O utput 1
RS FLIP-FLOP
RSF_
ESN = 000
R
S et
S
E
E xec. S eq. N o.
(H)
.................. 001 to 250
S
T
U P
N
I
INPUT S
(H)
........... loop tag.block tag.output ( null )
R
T
U P
N
I
S N
INPUT R
(H)
........... loop tag.block tag.output ( null )
L P U T S A
P ower U p LAST
(S)
................... NO/YES (YES)
P ulse Input
RISING EDGE TRIGGER
O1 O utput 1
RISING EDGE
RTG_
ESN = 000
P
E S N
E
xec.
S
eq.
N
o.
(H)
.............. 001 to 250
P T U P N I
INPUT P
(H)
........
loop tag.block tag.output ( null )
TRIGGER