Advantages Of Using Logo - Siemens LOGO! 24RC Manual

Applications

8.3.2 Advantages of Using LOGO!

If you use a LOGO! module you require fewer switching
devices. That saves you installation time and space in the
control cabinet. Under certain circumstances it may even
allow you to use a smaller control cabinet.
Additional options when using LOGO!
The free output (Q4) can be used as a potential-free
signaling contact in the event of a fault or a power fail-
ure.
It is possible to stagger the switching-off of the fans.
These functions can be implemented without additional
switching devices.
Functional block diagram of the enhanced LOGO! solution
The fans at Q1 and Q2 are switched on and off as shown in
the following circuit:
On I1
Fault Q3
I2
Off
Exhaust air flow
sensor
Q1 exhaust fan
Exhaust air flow
sensor
I3
Q2 exhaust fan
Fresh-air flow
sensor
I4
166
x
I3
x
x
T=
10 s
x
T=
10 s
T=
30 s
x
T=
10 s
x
Off I2
LOGO! Manual
A5E00067781 01
Q1
Exhaust
fan
Q2
Fresh-air
fan
Q3
Fault