User Manual

Applications
IDEC SmartRelay Manual 279
8.3.2 Advantages of using IDEC SmartRelay
The IDEC SmartRelay solution requires less switchgear.
That saves you installation time and space in the control
cabinet. You might even be able to use a smaller switching
cabinet.
Additional IDEC SmartRelay options
• The free output (Q4) can be used as isolated signal
co
ntact for reporting faults or power failure.
• It is possible to switch off of the fans by means of a
se
quential circuit.
These functions can be implem
ented without additional
switchgear.
Block diagram of the extended IDEC SmartRelay solution
The fans at Q1 and Q2 are switched on and off by means of
the follow
ing circuit:
x
T=
10 s
T=
30 s
Q1
Q2
I2
Q3
x
x
I3
I2
T=
10 s
T=
10 s
x
x
x
I3
I4
Q3
I1
Q2
On
Fault
Off
Exhaust air
flow sensor
Q1 exhaust fan
Exhaust air
flow sensor
Fresh-air fan
Fresh-air flow
sensor
Off
Exhaust
fan
Fresh-air
fan
Error