Siemens SIMATIC S7-200

Latching
2.5 A faster way to create logic state latches
Getting Started - Advanced
Training Documents, 09/2007, A5E01469795B
19
2.5 A faster way to create logic state latches
Instead of feeding back the output, as in the previous example, here the
functions "Set" and "Reset" are used instead. Have a look at the ladder
diagram below.
,
,
4
6

4
5

1HWZRUN
For the "Set" operation -(S), a
switching pulse at I0.0 has the
effect that Q0.0 is activated in a
steady state.
For the "Reset" operation -(R), a
switching pulse at I0.1 has the
effect that Q0.0 is deactivated
again.
-(S) Set
-(R) Reset
4
,
4
,
6

5

7KHFRLOV 66HW4WR
  55HVHW4WR
DUHXVHGIUHTXHQWO\LQ3/&SURJUDPVWRVZLWFK
RXWSXWVRUELWPHPRULHV21RU2))WRDVWHDG\
VWDWHZKHQDVHULHVFRQQHFWHGFRQWDFWLVEULHIO\
RSHUDWHG
$VHWRXWSXWRUPHPRU\ELWUHPDLQVVHW
XQWLOLWLVUHVHWE\WKH5VWDWHPHQW
,IWKHVHWFRLODQGWKHDVVRFLDWHGUHVHWFRLO
RIDQRXWSXWERWKKDYHVLJQDOWKHODVW
RSHUDWLRQLQWKHSURJUDPWDNHVSULRULW\
Steady-state
setting of
value with (S)
Resetting with
(R)
Last
operation in
cycle has
priority