Siemens LOGO! - Page 151

143
LOGO! Manual
A5E00380835-01
Parameters T
H
and T
L
Note the preset values for the parameters T
H
and T
L
in
Chapter 4.3.2.
Timing diagram
Trg
T
H
T
H
T
a
expires
Q
T
L
T
a
expires
T
L
T
H
T
L
The bold section
of the timing dia-
gram is also
shown in the on/
off-delay symbol.
Functional description
The time T
H
is triggered with a 0 to 1 transition at input Trg.
If the status at input Trg is 1 at least for the duration of the
time T
H
, the output is set to 1 on expiration of the time T
H
(the output follows the input with on-delay).
The time is reset when the signal at input Trg is reset to 0
before the time T
H
has expired..
A 1 to 0 transition at input Trg triggers the time T
L
.
If the status at input Trg is 0 at least for the duration of the
signal T
L
, the output is set to 0 on expiration of the time T
L
(the output follows the input with off-delay).
The time is reset when the signal at input Trg changes to 1
again before the time T
L
has expired.
If retentivity is not set, output Q and the expired time are
reset after a power failure.
LOGO! functions