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IC 40 · Edition 07.18
7
Application
1 .1 .3 Continuous control by three-point step signal
The actuator IC 40 is controlled by the three-point step
controller 3PS and moves the butterfly valve BVA to the
ignition position. The burner starts.
Once the burner is operating, the operation signalling
contact of the burner control unit BCU 460 closes. The
BCU issues the controller enable signal to the tempera-
ture controller. The butterfly valve opens or closes be-
tween the low-fire and high-fire rate positions depend-
ing on the capacity demand of the burner. When the
three-point step signal is disconnected, the butterfly
valve stops at its current position.
If both inputs on the IC 40 (DI 1 and DI 2) are activated
after the burner has been shut down, the butterfly valve
closes further than the low-fire rate position (see Op-
erating mode 12, 3-point step operation with low posi-
tion).
DI 1 DI 2
IC 40 position
Valve position
Off
Off
Idle/Stop
Idle
On
Off
Open to high position
Open to high-fire rate
Off
On
Close to middle position
Close to low-fire rate
On
On
low
Valve closes further
VAG
BVA
BCU 460
IC 40
12
L1, N, PE
4
4
DI 1
7
DI 2
18
19
16
17
9
5
3
BIO/
BIC
µC
V1
M
3PS
P
µC
VAG
VAS
PLC