25
LOGO! manual
EWA 4NEB 712 6006-02
3.5.3 Off-delay
The off-delay is represented in a cir-
cuit diagram by a relay with off-
delay:
In LOGO! the symbol for the off-
delay is as follows:
Trg
R
T
Q
Trg input You start the time for the off-delay by means of the Trg input (Trg
stands for trigger)
R input You reset the time for the off-delay and set the output to 0
via the R (reset) input (R has priority over Trg)
T parameter T is the time after which the output is switched off (the output sig-
nal changes from 1 to 0).
Timing diagram
Trg
T
TT
a
starts
Q
R
The bold part of the
timing diagram appears
in the off-delay symbol.
When the Trg input takes on the state 1, the output (Q) switches to 1 im-
mediately. If the state of Trg changes from 1 to 0, LOGO!’s current time
T
a
is started and the output remains set. If T
a
reaches the values set via T
(T
a
=T), the output (Q) is reset to 0 (off-delay).
If the Trg input is switched on and off again, the time T
a
starts again.
You reset the time T
a
and the output via the R (reset) input before the time
T
a
has elapsed.
Applications
Automatic stairway lighting system
Programming LOGO!
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